ngaruroro, tūtaekurī, karamū river and ahuriri estuary catchments · 2020-03-09 · n) levels at...

Ngaruroro, Tūtaekurī, Karamū River and Ahuriri Estuary Catchments State and Trends of River Water Quality and Ecology January 2020 HBRC Report No. 5422

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Environmental Science

Ngaruroro, Tūtaekurī, Karamū River and Ahuriri Estuary Catchments State and Trends of River Water Quality and Ecology January 2020 HBRC Report No. 5422

Prepared By: Sandy Haidekker, Senior Scientist - Water Quality and Ecology Anna Madarasz-Smith, Team Leader Marine & Coasts

Reviewed By: Jeff Smith – Manager Science

Approved By: Iain Maxwell – Group Manager Resource Management

Signed:

Ngaruroro, Tūtaekurī, Karamū River and Ahuriri Estuary Catchments

Contents

Executive summary ....................................................................................................................... 7

1 Introduction ........................................................................................................................ 9

1.1 TANK Catchment Descriptions and Land Use Overview ................................................... 10

1.2 Description of the Ngaruroro River Catchment ................................................................ 10

1.3 Description of the Tūtaekurī River Catchment ................................................................. 15

1.4 Description of the Karamū Stream Catchment ................................................................. 19

1.5 Waitangi Estuary ............................................................................................................... 23

1.6 Description of the Ahuriri Catchment ............................................................................... 25

1.7 Recreational usage and water quality in the TANK catchments ....................................... 27

1.8 SOE Water Quality Data – Methods and Analysis ............................................................. 27

2 Water Quality in the Ngaruroro and Tūtaekurī River Catchments: Long-term SOE data ........ 37

2.1 Nutrients ........................................................................................................................... 37

2.2 Nitrate-nitrogen and ammonia-nitrogen toxicity ............................................................. 52

2.3 Water Clarity – Black disc and turbidity ............................................................................ 59

2.4 Bacteriological water quality – E. coli ............................................................................... 65

2.5 Dissolved oxygen ............................................................................................................... 71

2.6 Biological indicators .......................................................................................................... 77

2.7 Summary and conclusion for the Ngaruroro and Tūtaekurī River catchments ................ 88

3 Water Quality of the Karamū and Ahuriri Catchments: Long-term SOE data ........................ 89

3.1 Nutrients ........................................................................................................................... 89

3.2 Nitrate-nitrogen and ammoniacal-nitrogen toxicity ....................................................... 100

3.3 Water Clarity – Black disc and turbidity .......................................................................... 104

3.4 Bacteriological water quality – E. coli ............................................................................. 110

3.5 Dissolved oxygen ............................................................................................................. 115

3.6 Biological indicators ........................................................................................................ 120

3.7 Stormwater ..................................................................................................................... 127

3.8 Summary and conclusion for the Karamū and Ahuriri catchments ................................ 129

4 Acknowledgements ......................................................................................................... 131

5 References ...................................................................................................................... 132

Appendix A Summary statistics by flow in the Ngaruroro and Tūtaekurī catchments ............. 135


Appendix B Summary statistics by flow in the Karamū and Ahuriri catchments ..................... 147

Appendix C Trend analysis results for water quality variables ............................................... 155

Appendix D Regional ranking tables for select water quality variables ................................... 161

Appendix E NPS-FW (2014) NOF attribute tables .................................................................. 172

Appendix F Summary of NOF bands for E.coli, Nitrate-nitrogen and Ammonia-nitrogen. ....... 175

Tables Table 1-1: Catchment characteristics of the major Ngaruroro catchment zones. 14 Table 1-2: Catchment characteristics of the major Tūtaekurī catchment zones. 17 Table 1-3: Catchment characteristics of the Karamū Stream. 21 Table 1-4: Catchment characteristics of the Ahuriri Estuary. 26 Table 1-5: Categories of periphyton/aquatic plants for cover assessments. 28 Table 1-6: Summary of relevant water quality guidelines for the TANK catchments. 32 Table 1-7: Attributes from the National Policy Statement for Freshwater Management 2014. 33 Table 2-1: Trend analysis results for TN and TP at Ngaruroro and Tūtaekurī SOE sites period

2012 to 2018. 43 Table 2-2: Trend analysis results for DIN and DRP at Ngaruroro and Tūtaekurī SOE sites period

2012 to 2018. 49 Table 2-4: NPS-FM (2014) NOF band summary for nitrate-nitrogen and ammonia-nitrogen at

Tūtaekurī and Ngaruroro SOE sites for the period 2013 to 2018. 54 Table 2-5: Trend analysis results for nitrate-nitrogen (NO3-N) at Ngaruroro and Tūtaekurī SOE

sites period 2012 to 2018. 56 Table 2-6: Trend analysis results for black disc clarity and turbidity at Ngaruroro and Tūtaekurī

SOE sites period 2012 to 2018. 63 Table 2-7: NPS-FM NOF bands (MfE, 2018) for E.coli in the Tūtaekurī and Ngaruroro catchments.68 Table 2-7: Trend analysis results for E. coli at Ngaruroro and Tūtaekurī SOE sites period 2012 to

2018. 69 Table 2-8: MCI quality classes as defined by Stark and Maxted (2007). 81 Table 3-1: Trend analysis results for TN and TP at Karamū and Ahuriri SOE sites period 2012 to

2018. 92 Table 3-2: Trend analysis results for DIN and DRP at Karamū and Ahuriri SOE sites period 2012

to 2018. 97 Table 3-3: NPS-FW (2014) NOF band summary for freshwater river attributes at Karamū and

Ahuriri SOE sites for the period 2013 to 2018. 100 Table 3-4: Trend analysis results for nitrate-nitrogen (NO3-N) at Karamū and Ahuriri SOE sites

period 2012 to 2018. 102 Table 3-5: Trend analysis for black disc clarity and turbidity at Karamū and Ahuriri SOE sites

period 2012 to 2018. 107 Table 3-6: NPS-FM bands (MfE, 2018, MfE, 2017) for E.coli at the Karamū and Ahuriri SOE sites.112 Table 3-7: Trend analysis results for E. coli for SOE monitoring sites at Karamū and Ahuriri SOE

sites. 113

Ngaruroro, Tūtaekurī, Karamū River and Ahuriri Estuary Catchments 5

Table 3-8: Sources of stormwater derived contaminants that may affect values associated with the Karamū and Ahuriri receiving environments. 127

Figures Figure 1-1 Location of the TANK catchments. 11 Figure 1-2: Ngaruroro River catchment and its State of the Environment (SOE) monitoring sites

for water quality and ecology. 13 Figure 1-3: Location of the Tūtaekurī River catchment and its State of the Environment (SOE)

monitoring sites for water quality and ecology. 16 Figure 1-4: Ngaruroro and Tūtaekurī River catchments land cover database classes

(amalgamated). 18 Figure 1-5: Location of the Karamū and Ahuriri catchments and its State of the Environment

(SOE) monitoring sites for water quality and ecology. 20 Figure 1-6: Karamū Stream and Ahuriri Estuary catchments land cover database classes

(amalgamated). 22 Figure 1-7: Location of the Waitangi Estuary. 24 Figure 2-1: Total nitrogen (TN) levels at Ngaruroro and Tūtaekurī SOE sites. 39 Figure 2-2: Total phosphorus (TP) levels at Ngaruroro and Tūtaekurī River SOE sites. 40 Figure 2-3: 5 year median TN levels at Ngaruroro and Tūtaekurī SOE sites including trend

direction. 41 Figure 2-4: 5 year median TP levels at Ngaruroro and Tūtaekurī SOE sites including trend

direction. 42 Figure 2-5: DIN concentrations at Ngaruroro and Tūtaekurī SOE sites. 45 Figure 2-6: DIN concentrations at Ngaruroro and Tūtaekurī SOE sites in relation to proposed NOF

DIN attribute bands (MfE, 2019). 46 Figure 2-7: Dissolved reactive phosphorus (DRP) levels at Ngaruroro and Tūtaekurī SOE sites. 47 Figure 2-8: DRP concentrations at Ngaruroro and Tūtaekurī SOE sites in relation to proposed

NOF DIN attribute bands (MfE, 2019). 48 Figure 2-9: 5 year median DIN levels at Ngaruroro and Tūtaekurī SOE sites including trend

direction. 50 Figure 2-10: 5 year median DRP levels at Ngaruroro and Tūtaekurī SOE sites including trend

direction. 51 Figure 2-11: Nitrate - nitrogen (NO3-N) levels at Ngaruroro and Tūtaekurī SOE sites. 55 Figure 2-12: 5 year median NO3-N levels at Ngaruroro and Tūtaekurī SOE sites including trend

direction. 57 Figure 2-13: Black disc viewing distance assessment to measure water clarity. 60 Figure 2-14: Water clarity (black disc measurements) at Ngaruroro and Tūtaekurī SOE sites. 61 Figure 2-15: Turbidity (NTU) at Ngaruroro and Tūtaekurī River SOE sites. 62 Figure 2-16: 5 year median turbidity levels at Ngaruroro and Tūtaekurī SOE sites including trend

direction. 64 Figure 2-17: Bacteriological water quality levels (E. coli ) at Ngaruroro and Tūtaekurī SOE sites. 66 Figure 2-18: 5 year median E.coli levels at Ngaruroro and Tūtaekurī SOE sites including trend

direction. 70 Figure 2-19: Schematic of the major processes influencing dissolved oxygen concentration in

rivers. 72


Figure 2-20: Dissolved oxygen saturation at Ngaruroro and Tūtaekurī SOE sites. 73 Figure 2-21: Dissolved oxygen concentration at Ngaruroro and Tūtaekurī SOE sites. 74 Figure 2-22: 5 year median DO saturation at Ngaruroro and Tūtaekurī SOE sites including trend

direction. 75 Figure 2-23: 5 year median DO concentration at Ngaruroro and Tūtaekurī SOE sites including

trend direction. 76 Figure 2-24: Periphyton cover (%PeriWCC) at Ngaruroro and Tūtaekurī SOE sites. 78 Figure 2-25: MCI levels at Ngaruroro and Tūtaekurī SOE sites. 82 Figure 2-26: 5 year median MCI levels at Ngaruroro and Tūtaekurī SOE sites including trend

direction. 83 Figure 2-27: Physical habitat: a critical component of stream health. 85 Figure 2-28: Rapid Habitat Assessment score (RHA score) at Ngaruroro and Tūtaekurī SOE sites. 87 Figure 3-1: Total Nitrogen (TN) levels at Karamū and Ahuriri SOE sites. 90 Figure 3-2: Total Phosphorus (TP) levels at Karamū and Ahuriri SOE sites. 91 Figure 3-3: 5 year median TN levels at Karamū and Ahuriri SOE sites including trend direction. 93 Figure 3-4: 5 year median TP levels at Karamū and Ahuriri SOE sites including trend direction. 94 Figure 3-5: Dissolved inorganic nitrogen (DIN) levels at Karamū and Ahuriri SOE sites. 96 Figure 3-6: Dissolved reactive phosphorus (DRP) levels at Karamū and Ahuriri SOE sites. 97 Figure 3-7: 5 year median DIN levels at Karamū and Ahuriri SOE sites including trend direction. 98 Figure 3-8: 5 year median DRP levels at Karamū and Ahuriri SOE sites including trend direction.99 Figure 3-9: Nitrate-nitrogen (NO3-N) levels at Karamū and Ahuriri SOE sites. 101 Figure 3-10: 5 year median nitrate-nitrogen levels at Karamū and Ahuriri SOE sites including trend

direction. 103 Figure 3-11: Water clarity measured as black disc horizontal sighting distance for Karamū and

Ahuriri SOE sites. 105 Figure 3-12: Water clarity measured as turbidity (NTU) for Karamū and Ahuriri SOE sites. 106 Figure 3-13: 5 year median black disc levels at Karamū and Ahuriri SOE sites including trend

direction. 108 Figure 3-14: 5 year median turbidity levels at Karamū and Ahuriri SOE sites including trend

direction. 109 Figure 3-15: Bacteriological water quality levels measured as E. coli counts (cfu/100ml) at Karamū

Stream and Ahuriri Estuary SOE monitoring sites. 111 Figure 3-16: 5 year median E.coli levels at Karamū and Ahuriri SOE sites including trend direction.114 Figure 3-17: Dissolved oxygen concentration at Karamū and Ahuriri SOE sites. 116 Figure 3-18: Dissolved oxygen saturation at Karamū and Ahuriri SOE sites. 117 Figure 3-19: 5 year median DO saturation at Karamū and Ahuriri SOE sites including trend

direction. 118 Figure 3-20: 5 year median DO concentration at Karamū and Ahuriri SOE sites including trend

direction. 119 Figure 3-21: Macrophyte abundance at Karamū and Ahuriri SOE sites. 121 Figure 3-22: MCI levels at Karamū and Ahuriri SOE sites. 123 Figure 3-23: 5 year median MCI levels at Karamū and Ahuriri SOE sites including trend direction.124 Figure 3-24: Rapid Habitat Assessment score (RHA score) at Karamū and Ahuriri River SOE

monitoring sites. 126


Executive summary Ngaruroro and Tūtaekurī catchments:

• Toxicity effects on aquatic organisms from nitrate and ammonia were not an issue anywhere in the Ngaruroro and Tūtaekurī catchments, as concentrations were always low. Ammonia levels were mostly below detection limit.

• Escherichia coli (E. coli) levels were very low in both catchments and were below the lowest guideline (‘alert’-) level. All mainstem sites in the Ngaruroro and Tūtaekurī rivers were suitable for primary contact recreation under the NPS-FM framework. Some tributaries fell into the D Band (not suitable for primary contact recreation), but when full immersion activity is limited to normal flows (<median flows), all sites were suitable.

Ngaruroro catchment

The Ngaruroro mainstem is in excellent condition in the upper to middle catchment. The lower reaches showed some minor enrichment in nutrients. Water quality parameters in general showed a minor upstream to downstream decline, which was reflected in the macroinvertebrate community. Periphyton cover was indicative of a good ecological condition, but recreational guidelines were just exceeded on rare occasions at Fernhill. Overall water quality and ecology of the Ngaruroro River mainstem was healthy.

Water clarity decreased while turbidity increased from upstream to downstream in the Ngaruroro catchment. The mid to lower mainstem water clarity was below contact recreation guidelines. Soft rocks in the catchment increases erosion risk, and sediment appears to enter the Ngaruroro from the tributaries as well as the riparian margin of the mainstem. Sediment loads are relevant to the receiving Waitangi Estuary.

All Ngaruroro tributaries (other than the Ohara Stream) were enriched in nutrients, especially phosphorus, which was always above guideline levels. The influence of nutrient loads coming from the tributaries into the mainstem had only a minor effect on the water quality in the mainstem Ngaruroro, because large volumes of water with high water quality from the pristine upper catchment dilutes the influence of the tributaries. But nutrient loads coming from the tributaries are relevant for the health of the Waitangi Estuary as receiving environment.

Tūtaekurī catchment

The Tūtaekurī mainstem showed some enrichment in nutrients from upstream to downstream, particularly in phosphorus, which was always above guideline levels at the lower mainstem sites. MCI also showed a gradient from upstream to downstream, and declined from excellent to fair towards the lower reaches.

Tūtaekurī tributaries had water quality issues similar to the Ngaruroro tributaries, with elevated nutrient concentrations. The high phosphorus concentrations were mostly above guidelines. MCI was good across all tributary sites. Periphyton biomass was high at the SOE site in the Mangatutu Stream, and low at the sites in the upper Mangaone River. The effect of tributary nutrient loads on mainstem water quality was greater in the Tūtaekurī than in the Ngaruroro, because the volume of water coming from the pristine upper catchment is lower and the dilution effect is therefore less than in the Ngaruroro. Nutrient loads are important to manage with regards to the health of the receiving Waitangi estuary.

8 Ngaruroro, Tūtaekurī, Karamū River and Ahuriri Estuary Catchments

Karamū and Ahuriri catchments:

The results of water quality and ecology SOE assessments in the Karamū and Ahuriri catchments show streams are highly compromised in terms of ecosystem health and life supporting capacity. Overall, the condition at SOE sites in the Karamū and Ahuriri catchments ranked poorest of Hawke’s Bay in many factors. Most sites in the Karamū had amongst the highest concentrations of nutrients and E. coli, and lowest MCI and habitat scores, of all sites in Hawke’s Bay.

Nutrient concentrations were generally high at the Karamū and Ahuriri SOE sites. Nitrogen (TN and DIN) concentrations were variable between sites, with some sites up to 10 times above trigger values and others generally below. Phosphorus (TP and DRP) concentrations were always above ANZECC trigger values at all sites, up to 16 times higher than the guideline concentration.

Ammonia and nitrate toxicity effects were likely to be minimal under average, long-term conditions (NOF Band A and B, 99% and 95% species protection respectively). Most sites showed some probability of nitrate toxicity effects of short-term peaks and critical events, and were in NOF Band C (80% species protection). Ammonia toxicity effects for peak ammonia concentrations were in the A or B band for most sites except the Taipo Steam (C Band).

Bacteriological water quality in the Karamū and Ahuriri catchments showed that SOE sites have E.coli concentrations categorised as not suitable for primary contact recreation (except for the Poukawa Stream). High E.coli concentrations were not limited to rainfall and subsequent high flow events. The sites were also graded not swimmable under average flow conditions.

Several SOE sites were at risk for having critically low oxygen levels that are likely to stress fish, invertebrates and other aquatic organisms. Excessive macrophyte growth is contributing to this at most sites, and breakdown of organic matter may be another cause for low oxygen levels.

Biological indicators showed that most SOE sites were highly compromised. The macroinvertebrate community was in a poor condition at all sites. There was excessive macrophyte growth at most sites with adverse effects on water quality, particularly dissolved oxygen. Physical habitat was poor at most Karamū and Ahuriri SOE sites, particularly in terms of habitat heterogeneity and riparian condition.

The Taipo, Awanui and Karewarewa streams were the most compromised streams in the Karamū and Ahuriri catchments.


1 Introduction This report summarises state and trends in river water quality and ecology across the Ngaruroro River, Tūtaekurī River, Ahuriri and Karamū catchments (TANK). The report is one of six State of Environment (SOE) reports for the Hawke’s Bay region summarising river water quality and ecology data collected up to June 2018. The 6 SOE reports cover the river catchments and water management zones listed below.

(A) Porangahau River/Southern Coastal

(B) Tukituki River

(C) TANK (Tūtaekurī River, Ahuriri Estuary, Ngaruroro River, Karamū Stream)

(D) Mohaka River

(E) Waikari River/Esk River/Aropoanui River

(F) Wairoa River/Northern Coastal

Each technical report within the series aims to provide an analysis and summary of water quality and biomonitoring data collected by HBRC up to and including June 2018, covering in particular the following points:

• the state of water quality and aquatic ecology in the rivers and streams within the subregion or water management zone considered;

• Compliance of the sites with relevant guidelines that are stipulated in either the Regional Resource Management Plan (RRMP), the Resource Management Act (RMA), the National Policy Statement for Freshwater Management (NPS-FM) or ANZECC (Australia and New Zealand Environment and Conservation Council) guidelines;

• Trends through time, i.e. are the water quality or the ecological indicators improving or deteriorating over time?

• Recommendations for further analysis of the data and future water quality monitoring in these catchments.

Hawke’s Bay Regional Council is working through a plan change for the TANK catchments to meet the requirements of the National Policy Statement for Freshwater Management (MfE, 2017, MfE, 2014). A stakeholder group was formed in 2012 to represent the wider community to look at the best way to manage the waterways of the Tūtaekurī, Ahuriri, Ngaruroro and Karamū catchments. The collaborative group (TANK Group) was tasked with assisting in the development of objectives, policies and rules for the plan change. The last TANK Group meeting was held on 26 July 2018. The previous SOE report (Haidekker et al., 2016) and updates with data used in this current report supported the plan change process with the information on the state of water quality and ecology in the river catchments, summarised by Haidekker (2019).

https://www.hbrc.govt.nz/hawkes-bay/projects/tank/whos-in-tank/


1.1 TANK Catchment Descriptions and Land Use Overview The four specific catchments of the TANK area are shown in Figure 1-1. The Tūtaekurī and Ngaruroro rivers have very different catchment characteristics compared to the Karamū and Ahuriri catchments. The Tūtaekurī and Ngaruroro are large 6th order rivers (Strahler ordering system 1952) and the catchments cover an area of approximately 836 km2 and 2,000 km2 respectively. The headwaters are in forested hills of the Kaweka and Ruahine ranges. The mainstems of both rivers are characterised by gravel beds that form wide, braided channels in the lower catchment.

The Karamū and Ahuriri catchments are smaller, approximately 500 km2 and 86 km2 respectively. The Karamū catchment covers most of the surface area of the Heretaunga Plains. The Ahuriri catchment, north of Napier, has small tributaries flowing into the Ahuriri Estuary. Most of the tributaries of both catchments drain lowland country, and have very low gradients with slow flowing water, and the streambed is often made up of fine gravel or sandy/silty substrate. This provides ideal growing conditions for aquatic plants (macrophytes). By contrast, algae are more commonly found in streams with faster flowing, stony substrates, like the Tūtaekurī and Ngaruroro rivers.

Due to significant differences in the stream ‘types’ of the Ngaruroro and Tūtaekurī catchments in comparison to the Karamū and Ahuriri catchments, this SOE technical report presents and discusses data on the Ngaruroro and Tūtaekurī rivers separately to the Karamū and Ahuriri.

1.2 Description of the Ngaruroro River Catchment The headwaters of the Ngaruroro River are in the forested areas of the Kaweka Range (north) and the Ruahine Range (south). Monitoring site locations are shown in Figure 1-2. In its upper catchment the Ngaruroro River is a fast flowing river in a bed of rocks, boulders and coarse gravel. This area is predominantly in native vegetation with some pasture down to Whanawhana. Between Whanawhana and Maraekakaho, the river is braided, flowing in a relatively wide and flat channel bordered by steep hill country and high river terraces. The land use in this part of the catchment is predominantly dry stock farming with land use changes occurring in the last 15 years (Table 1-1and Figure 1-4). There were two large intensive dairy operations, one on either side of the Ngaruroro River downstream of Whanawhana. The dairy farm on the true left bank has been converted to viticulture in 2016.

Downstream of Maraekakaho the river runs through plains and low rolling hill country and land use becomes more varied, including viticulture and cropping. The river channel is wide and flat, with a low gradient and a semi-braided morphology, constrained on each side by stopbanks. The area is a zone of groundwater recharge, losing surface water to groundwater between Ohiti and Fernhill. The aquifer is important to the region, providing water for multiple uses including irrigation, processing and industrial use, and is the water source for Hastings and Napier. The Ngaruroro River then flows eastwards to an estuary shared with the Tūtaekurī River. It flows into the Pacific Ocean at Hawke Bay, south of Napier.

The Ngaruroro catchment supports a significant brown trout and rainbow trout fishery. Angling activity is spread throughout the catchment, with the Ngaruroro mainstem above the Taruarau confluence and the Taruarau itself the most sought after fishery. Trout populations in the catchment are self-sustaining, with trout spawning occurring in the mainstem and a number of tributaries.


Figure 1-1 Location of the TANK catchments.


Recreational activities occur in many parts of the catchment. The Ngaruroro River upstream of Whanawhana is highly valued for white water kayaking particularly around Kuripapango, and flat-water kayaking occurs from there to the coast (Sinner and Newton, 2016). Jet-boating is popular from Maraekakaho to Whanawhana. Popular swimming locations are found at Kuripapango and at Chesterhope and Fernhill bridges.

The catchment also has significant ecological values, associated with aquatic and riparian ecosystems and with indigenous fauna and flora. Significant wetlands include lakes Runanga, Oingo, Hurimoana, Kautuku and Potaka, along with Pig Sty Swamp and Waitangi wetland. These support a large range of fish and bird species, some of which are threatened. Nineteen native fish species (8 with declining populations at a national level) can be found in the catchment and it is a stronghold for longfin eel, banded kokupu, lamprey, koaro, dwarf galaxiid and inanga in the Waitangi Estuary. The upper reaches are a stronghold for whio (blue duck). The lower braided reaches of the Ngaruroro support a range shorebirds, including banded dotterel, black-fronted dotterel, and South Island pied oystercatcher. The river, including its mouth are known to host breeding colonies of black-billed gulls. The habitat in the braided lower reaches are considered to be nationally outstanding avifauna habitat based on population estimates of the banded dotterel and black fronted dotterel (EPA, 2019).

HBRC monitors ecological health, water quality and flow across the Ngaruroro catchment (Figure 1-2). Three of the long-term state of the environment (SOE) sites for water quality and ecology are on the Ngaruroro River mainstem, and six are on the tributaries: Two sites (Waitio and Tūtaekurī-Waimate streams) are long-term SOE sites, three sites (Poporangi, Maraekakaho, and Ohiwa streams) were added for the TANK plan change in 2012, and one (Ohara Stream) in 2015. NIWA also monitors water quality and flow in Ngaruroro at Kuripapango and Chesterhope (Figure 1-2).

At the Ngaruroro at Hawke’s Bay Dairies site there has been a transition in land use from dairy to viticulture in 2016. The site name is not changed in this report to avoid confusion over the continuity of this long-term site.


Figure 1-2: Ngaruroro River catchment and its State of the Environment (SOE) monitoring sites for water quality and ecology. *Short-term monitoring site (3 years data)


Table 1-1: Catchment characteristics of the major Ngaruroro catchment zones. Information has been taken from the River Environment Classification (REC) and the Land Cover Data Base (New Zealand) version 4 (LCDB4), and Agribase (HBRC, 2016). Land use <1% not listed.

Zone Climate and Source-of-Flow categories (REC)

Geology (REC)

Land cover (LCDB4)

Upper Zone

Source to Whanawhana

Total catchment area

110880 ha

Cool wet (55%) climate with flow originating in mountain country, and Cool wet (44%) climate with flow originating in hill country, and Cool wet (1%) climate with flow originating in lowland country.

Volcanic acidic 62% Hard sedimentary 34% Miscellaneous 3%

Native Cover 82% Sheep and Beef 12% Exotic Forest 4% Forest - Harvested 1%

Middle Zone

Whanawhana to Fernhill


83226 ha

Cool wet (26%) climate with flow originating in hill country, and Warm dry (48%) / warm wet (3%) / cool dry (12%) / cool wet (5%) climate with flow originating in lowland country, and Cool wet (4%) climate with flow originating in mountain country, and Warm dry (1%) climate with flow originating in lakes.

Miscellaneous 34% Alluvium 28% Hard sedimentary 21% Volcanic acidic 17% Soft sedimentary 1%

Native Cover 21% Sheep and Beef 54% Beef 8% Exotic Forest 6% Deer 2% Perennial Crop 2% Dairy 1% Deciduous Hardwoods 1% Gravel or Rock 1%

Lower Zone

Fernhill to Coast


8094 ha

Warm dry (94%) climate with flow originating in lowland country, and Warm dry (6%) climate with flow originating in lakes

Alluvium 51% Miscellaneous 49%

Sheep and Beef 55% Perennial Crop 18% Short-rotation Cropland 12% Beef 4% River 4% Deciduous Hardwoods 1% Exotic Forest 1%


1.3 Description of the Tūtaekurī River Catchment The Tūtaekurī catchment is approximately 836 km2 in size and Figure 1-3 shows the locations of SoE monitoring sites. Its headwaters are in native vegetation in the Kaweka Range. Around the SOE site at Lawrence Hut the Tūtaekurī River passes through commercial pine forest. The river has good quality habitat for most of its length, with regular occurrence of riffles, pools and bends and a predominantly cobble streambed.

Dry stock farming dominates the middle catchment although approximately 7000 ha of dairy farming has been established over the last 10 to 15 years, mostly around Patoka (Table 1-2, Figure 1-4). Downstream of the Mangaone River confluence, the Tūtaekurī valley widens and flattens, and the river takes a braided morphology. Land use here is predominantly vineyards and orchards, with dry stock farming in the surrounding hills as well as peri-urban/commercial development.

The catchment holds significant ecological value associated with the aquatic and riparian ecosystems and indigenous fauna and flora. Seven native fish species with populations which are classified as ‘declining at a national level’ are found in the Tūtaekurī and it is an important catchment for lamprey and koaro.

There are a number of freshwater wetlands in the catchment which support a wide range of bird and fish species, the largest being the ecologically significant Lake Te Rotokare. Preliminary results from the latest river birds survey in 2019 (in progress, unpublished data) suggest that the lower braided section if the Tutaekuri river supports substantial populations of shorebirds, namely banded dotterel, black-fronted dotterel and pied stilts.

The catchment supports a significant brown and rainbow trout fishery with good angling opportunities in the Mangatutu and the Tūtaekurī mainstem. Trout populations are self-sustaining with spawning occurring in a number of tributaries.

The Tutaekuri catchment is popular for a range of other recreational activities, including tramping, swimming and kayaking. In the upper reaches, the Donald River is valued for whitewater kayaking, while flatwater kayaking occurs in the lower catchment near Puketapu. Popular swimming locations are found near Puketapu and at Guppy Rd near Taradale where the recreational grade is recorded as fair, due to occasional bacterial contamination. The lower section of the Tūtaekurī is fenced to keep cattle out and to support the high recreational value of the river.

HBRC monitors ecological health and water quality at five SOE sites in the Tūtaekurī catchment, of which three have long-term data records. The three sites on the Tūtaekurī mainstem are Lawrence Hut, upstream of the Mangaone River confluence at Rissington, and Brookfields Bridge. The two remaining sites are in the two biggest tributaries, the Mangatutu and the Mangaone Rivers (Figure 1-3).


Figure 1-3: Location of the Tūtaekurī River catchment and its State of the Environment (SOE) monitoring sites for water quality and ecology.


Table 1-2: Catchment characteristics of the major Tūtaekurī catchment zones. Information has been taken from the River Environment Classification (REC) and the Land Cover Data Base (New Zealand) version 4 (LCDB4), and Agribase (HBRC, 2016). Land use <1% not listed.


Geology (REC)

Land cover (LCDB4)

Upper Zone Source to Lawrence Hut Total catchment area 10060 ha

Cool wet (59%)/ cool extremely wet (4%) climate with flow originating in hill country, and Cool extremely wet (29%)/ cool wet (8%) climate with flow originating in mountain country.

Volcanic acidic 64% Hard sedimentary 27% Miscellaneous 9%

Native Cover 77% Plantation forestry 21%

Middle Zone Lawrence Hut to Puketapu Total catchment area 68553 ha

Cool Wet (38%) climate with flow originating in hill country, and Warm wet (39%)/ warm dry (20%) climate with flow originating in lowland country, and Cool wet (3%) climate with flow originating in mountain country.

Miscellaneous 48% Alluvium 2% Volcanic acidic 45% Soft sedimentary 5%

Sheep and beef 61% Plantation forestry 18% Native Cover 17% Dairy 3% Orchards/Vineyards 1%

Lower Zone Puketapu to coast Total catchment area 3214 ha

Warm dry (82%) /Cool wet (18%) climate with flow originating in lowland country.

Miscellaneous 69% Alluvium 31%

Sheep and beef 63% Orchards/Vineyards 10% Short-rotation Cropland 9% Plantation forestry 8% Built-up Area 4% Beef 1%


Figure 1-4: Ngaruroro and Tūtaekurī River catchments land cover database classes (amalgamated).


1.4 Description of the Karamū Stream Catchment The Karamū catchment is approximately 490 km2, extending south from Awatoto to Havelock North and west to the Raukawa Range. The Karamū Stream and its tributaries drain the Poukawa Basin, the Kohinurakau, Kaokaoroa and Raukawa Ranges and a large part of the Heretaunga Plains (Figure 1-5).

The catchment covers the majority of the Heretaunga Plains which has been developed extensively for agriculture and comprises some of the most productive cropping areas in New Zealand. The Karamū catchment is the predominant region in Hawke’s Bay for orcharding, cropping, and viticulture, while the southwestern half of the catchment primarily supports dryland sheep and beef with the exception of the Poukawa Basin, which is a significant cropping area (Table 1-3 and Figure 1-6).

Waterways in the Karamū catchment have been extensively modified for flood protection purposes. The current Karamū Stream occupies a former course of the Ngaruroro River. Flooding of the productive, southern area of the Heretaunga Plains has been an issue since the 1850s. In 1969, as part of the Heretaunga Plains Flood Protection scheme, the Ngaruroro River was diverted to the north, leaving the Karamū and Raupare streams to feed the lower Karamū Stream or, as it is also known, the Clive River and Ngaruroro Tawhito (the ‘old’ Ngaruroro).

There are several freshwater wetlands in the catchment which are ecologically significant, the largest being Lake Poukawa and Pekapeka Swamp. They support a significant number of bird species, some of which are threatened.

HBRC monitors water quality at six SOE sites across the Karamū catchment in the Poukawa, Karewarea, Herehere, Awanui and Raupare streams and the Clive River (Figure 1-5).


Figure 1-5: Location of the Karamū and Ahuriri catchments and its State of the Environment (SOE) monitoring sites for water quality and ecology. *Short-term monitoring site (4 years data).


Table 1-3: Catchment characteristics of the Karamū Stream. Information has been taken from the River Environment Classification (REC) and the Land Cover Data Base (New Zealand) version 4 (LCDB4), and Agribase (HBRC, 2016). Land use <1% not listed.

Zone Climate and Source-of-flow categories (REC)

Geology (REC)

Land cover (LCDB4)

Karamū Stream


51462 ha

Warm dry (97%)/ cool dry (3%) climate with flow originating in lowland country

Hard sedimentary 34% Soft Sedimentary 28% Alluvium 26% Miscellaneous 10% Volcanic acidic 2%

Sheep and Beef 53% Perennial Crop 16% Short-rotation Cropland 12% Beef 8% Built-up Area (settlement) 6% Exotic Forest 1% Urban Parkland/Open Space 1%


Figure 1-6: Karamū Stream and Ahuriri Estuary catchments land cover database classes (amalgamated).


1.5 Waitangi Estuary The Waitangi estuary (Figure 1-7) is where the Tūtaekurī, Ngaruroro and Karamū Rivers meet the sea. The estuary includes a variety of important habitats including subtidal seagrass beds, intertidal flats, salt marsh and two associated freshwater wetlands at Muddy Creek and the Horseshoe wetland. These habitats host a broad diversity of flora and fauna. There is a large number of bird and fish species (some threatened) that use this area during some or all of their life cycle. In the Regional Coastal Environment Plan (HBRC, 2012), the Waitangi Estuary is classified a Significant Conservation Area which affords the estuary particular protection.

The presence of rich natural resources has meant that this area has always been important to Māori. Te Awapuni, which is the Māori name for the mouth of the Ngaruroro River, was once an important pā site. Hawke’s Bay’s first mission was established adjacent to the pā by William and Elizabeth Colenso in 1844. This was washed away in 1897. At this time the Waitangi estuary was linked with the mouth of the Tukituki River. This area has been greatly modified both by natural processes such as storm events, floods and wave action as well as the construction of flood defences, land drainage and pump stations. The wetlands that exist now are a fragment of their past extent.

Despite this extensive modification, the Waitangi estuary is still valued as a recreational area. Dependent on the weather conditions, the estuary is extensively used by kayakers, kite surfers, jet boaters, fishermen and surfers.

The water quality, especially sediment loads, coming from the Ngaruroro, Tūtaekurī and Karamū catchments influences the state of the estuary as it is the receiving environment of all three catchments. The state and trends of water quality within the Waitangi estuary is reported on in the TANK Coastal report (Madarasz-Smith et al., 2016).


Figure 1-7: Location of the Waitangi Estuary.


1.6 Description of the Ahuriri Catchment The Ahuriri Estuary is located in the urban centre of Napier. The catchment, remnants of the old Ahuriri Lagoon, is relatively small at 4,564 hectares. The Ahuriri is Hawke’s Bay’s most urbanised catchment and includes Napier and surrounding suburbs north to Bay View and south to Awatoto. Over 70% of the stormwater generated through the urban and industrial areas in Napier is discharged into the Ahuriri Estuary through tide gates adjacent to the Expressway, and through a pump station located at the top of the estuary, near Onehunga Road. This network of pumped and gravity fed streams protects the Napier area from flooding.

Over half of the Ahuriri catchment area is used for dry stock farming, and a significant part is urban area (Table 1-4). The Ahuriri Estuary itself is a shallow microtidal estuary with an area of approximately 270 hectares. Due to its shallow nature the estuary is well mixed, and receives freshwater from the Taipo Stream, the County, Plantation and Purimu Streams, Wharerangi Stream, and a number of small 3rd order streams to the west. Freshwater inflows into the estuary are minimal compared to other estuaries in the region.

Despite extensive modification, reclamation, drainage, and discharges from the stormwater network, the estuary is recognised as a regionally and nationally significant area, with high wildlife and fisheries values. Over 70 species of resident and migratory waterbirds use the estuary as a feeding and roosting area. Almost 30 species of fish have been recorded in the estuary. In the Regional Coastal Environment Plan (HBRC, 2012), the Ahuriri Estuary is a gazetted wildlife refuge, and a Significant Conservation Area, which prioritises environmental values within the estuary.

The Ahuriri catchment has one long-term freshwater SOE monitoring site, which is located in Taipo Stream (Figure 1-5). In this report the site is included in the results and discussion of the Karamū SOE sites due to its similarity in stream type (lowland, slow-flowing stream). A wider monitoring programme of the Ahuriri catchment and estuarine water quality was established in 2014. The results of this monitoring are reported in the TANK coastal environment report (Madarasz-Smith et al., 2016).


Table 1-4: Catchment characteristics of the Ahuriri Estuary. Information has been taken from the River Environment Classification (REC) and the Land Cover Data Base (New Zealand) version 4 (LCDB4), and Agribase (HBRC, 2016). Land use <1% not listed.


Geology (REC)

Land cover (LCDB4)

Ahuriri Estuary

Total catchment area 14564 ha

Warm dry (99%) climate with flow originating in lowland country, and Cool dry (1%) with flow originating in hill country

Alluvium 30% Miscellaneous 69% Volcanic acidic 1%

Sheep and Beef 45% Built-up Area (settlement) 15% Beef 10% Short-rotation Cropland 7% Perennial Crop 6% Exotic Forest 6% Urban Parkland/Open Space 4% Herbaceous Saline Vegetation 2% Manuka and/or Kanuka 1%


1.7 Recreational usage and water quality in the TANK catchments The rivers and estuaries found within the TANK catchments are frequently used for recreational activities because of their proximity to major Hawke’s Bay population centres and ease of access. During a survey of recreational use of Hawke’s Bay rivers (Madarasz-Smith, 2010), the Clive (Karamū), Tūtaekurī and Ngarururo were rated the third, fourth and fifth most popular respectively. These 3 rivers are used for a variety of activities including kayaking, swimming, fishing, dog walking, picnicking, bird watching and kite-surfing. The same survey also highlighted that good water quality is one of the most important attributes that make a river appealing to the public and poor water quality is the most important attribute that makes sites unappealing. HBRC monitors recreational water quality at one site in the lower reaches of each of these rivers.

HBRC has a sampling site at Pandora pond which is situated close to the mouth of the Ahuriri estuary. The safe sheltered water, proximity to Napier and amenities make the Ahuriri the most well-used estuary in Hawke’s Bay. Pandora pond and the lower Ahuriri estuary are popular for swimming, kayaking, waka ama, picnicking and dinghy sailing. The Waitangi estuary is probably the next most used estuary in Hawke’s Bay and is a popular spot for kayaking, waka ama, jet boating, surfing, kite-surfing and fishing. There is no specific sampling site in the Waitangi estuary. However, sampling sites on the 3 rivers Ngaruroro, Tūtaekurī and Karamū are at the upper limit of the estuary.

Alongside the river and estuarine sites, HBRC monitors recreational water quality at 4 beach sites, which can at times come under the influence of these catchments. Tests for faecal bacterial contamination as an indicator for pathogens associated with human health risks are performed weekly during the summer months.

Hawke’s Bay’s main urban and agricultural centres are found within the TANK catchments. Urban and agricultural areas have elevated risks of poor recreational water quality due to increased levels of stormwater and agricultural runoff (Madarasz-Smith and Focht, 2019). Despite these risks, recreational water quality at popular bathing sites within the TANK catchments is typically of an acceptable standard. Elevated concentrations of bacteria generally only occur after periods of heavy rain.

1.8 SOE Water Quality Data – Methods and Analysis

1.8.1 Water quality and ecology assessments Water quality monitoring across the TANK catchments has been carried out by HBRC since 1980 as part of the State of the Environment (SOE) programme. The SOE monitoring programme was undertaken on a quarterly basis until June 2012, when monthly sampling began across the whole region. All data collection and analyses were undertaken in accordance with internal quality assurance and quality control processes and procedures.

In this report, water quality data is shown for 11 sites in the Ngaruroro catchment, and 5 sites in the Tūtaekurī catchment. Two sites, Ngaruroro at Kuripapango and Ngaruroro at Chesterhope, are monitored long-term by NIWA. All sites are long-term sites since the 1980’s, except for the Poporangi, Maraekakaho and Ohiwa streams in the Ngaruroro catchment, which were added to the SOE monitoring sites in 2012, and the Ohara Stream in 2015. The Mangatutu Stream in the Tūtaekurī catchment was sampled since 2012. Six sites have been sampled in the Karamū catchment, and one in the Ahuriri catchment, all of which are long-term sites.


Water quality parameters routinely measured across SOE monitoring sites include the following field-based measurements:

Turbidity (NTU or FNU)

Visual clarity (as black disc sighting distance in metres)

Dissolved oxygen (mg/L)

Conductivity (µS/cm)

pH

Water temperature (oC)

Water samples were collected at each site and submitted to Hill Laboratories (Hamilton) for analysis of total and dissolved nutrients (nitrogen and phosphorus), suspended solids, and faecal bacteria (as E. coli).

Visual periphyton assessments were introduced to the SOE programme in 2011 and were undertaken at most sites, subject to flow conditions and substrate type. Periphyton cover assessments were made at 20 points using a bathyscope. When possible, 5 points are distributed along 4 transects that traverse the width of the waterway. However, the distribution of points is adjusted at deeper and/or faster flowing sites if necessary. Assessments involved visually assessing the proportion of the river bed covered by each of nine periphyton or aquatic plant cover categories (Table 1-5). Periphyton cover categories were the same as those used by Kilroy et al. (2013). Classes were added for macrophyte and bryophyte cover which can be considerable at some sites.

Table 1-5: Categories of periphyton/aquatic plants for cover assessments. Adapted from those in Kilroy et al. (2013).

Cover category Description

No algae No algae visible (no colour perceived); stone surface not slippery or slimy

Film Fine, slightly slimy black, brown or greenish colouration, <0.5 mm thick (thin layer containing various algae including diatoms and Chlorophyta, but also bacteria and organic matter)

Mats Definite consolidated layer of algae from 0.5 mm to >5 mm thick, variable colours; often dominated by diatoms but can be a mixture of diatoms, Cyanobacteria, Rhodophyta,Chlorophyta. Note that Phormidium-dominated mats are recorded as a separate category. Assessed as thick > 2 mm or thin < 2 mm mats.

Sludge Loose, unconsolidated algae, easily dislodged; e.g. mucilage-rich accumulations of diatoms such as Cymbella

Phormidium Cyanobacterial mats, especially Phormidium; distinctive black, brown or whitish flecked mats with black/brown, smooth surface

Green filamentous Green filamentous algae, usually slimy and more than about 1 cm long; mainly Chlorophyta with some Xanthophyceae (Ochrophyta). Assessed as long > 2 cm or short < 2cm.


Cover category Description

Other filamentous Brown, reddish or other filaments, slimy or coarse, more than about 1 cm long. Includes Rhodophyta, filamentous diatoms and Chlorophyta covered with epiphytic diatoms. Assessed as long > 2 cm or short < 2cm.

Moss Bryophytes

Macrophytes Aquatic plants such as oxygen weed, Potamogeton etc

At macrophyte dominated monitoring sites, assessment of macrophyte abundance was performed using a modified version of the Waikato Region macrophyte monitoring protocol (Collier et al., 2007).

Macroinvertebrate samples were collected according to the Stark et al. (2001) ‘Protocol C2 – soft-bottomed, semi-quantitative’ or ‘Protocol C3 – hard bottomed, quantitative’, depending on whether the sediment characteristics at a site were hard (e.g. gravels and cobbles) or soft bottomed (e.g. silt with macrophytes). Five replicate 0.1m surber samples were taken at riffles in hard bottomed sites. A 0.3m2 D-net, scooped 3 times through key habitat features, was used at soft bottomed sites. For calculating metrics, all samples were assessed according to the hard bottomed MCI taxon scores, because there is uncertainty around whether soft-bottomed metrics can be compared with the hard-bottomed metrics (Unwin and Larned 2013). The vast majority of SOE sites in the region where macroinvertebrate samples are collected are hard-bottomed, and so hard bottomed metrics were used for consistency.

Coastal water quality has been monitored offshore of the Waitangi and Ahuriri estuaries 8 times per year since 2006 and is reported by Wade et al. (2016).

1.8.2 Trend analyses: Introduction and method Analysing trends of environmental monitoring data is important because environmental characteristics may exhibit changes over time that indicate a problem is emerging, or is improving. For example, if nitrate concentrations are increasing or decreasing at a particular site, the cause and significance of these changes may need to be identified.

Trend analyses in this report use non-parametric statistical approaches (seasonal Kendall trend tests). This approach is consistent with the approach used in our previous SOE reporting, and consistent with the approach taken for nationwide water quality analyses up until 2 years ago (Land, Air, Water Aotearoa: LAWA). LAWA is a national initiative that collects and analyses environmental datasets (including river water quality) from all regional councils around New Zealand. LAWA presents trend results for many of the same sites in this technical report, but they have recently adopted a different statistical analyses that relaxes the significance testing component of trend analyses. We do not think the current LAWA approach is appropriate for regional trend analyses, so have continued to use the previous and more traditional style of trend analysis outlined below (Kendall test with Thiel-Sen slope estimator).

Kendall tests are a non-parametric analysis technique that ranks data in order of magnitude, and then compares their ranking over time. This process can be undertaken for each separate ‘season’ or, in this case, month. These seasonal Kendall tests help identify whether variability in the water quality data is randomly distributed, or whether a significant trend exists over time. For example, did most of the higher ranked values occur in the last few years, or did higher values occur randomly over time? A ‘significant’ trend exists where there is a less than 5% probability (p< 0.05) that an observed data trend was a consequence of random data distribution. In other words, ‘significant’ means the observed trend is very unlikely to have occurred due to random variation.


Some of our monitoring sites have a long-term monthly record. Other sites only had monthly sampling for the latter part of the record, and quarterly sampling earlier. For most sites, monthly sampling began in 2012 which enabled a 6 year monthly record to be analysed. To make the most use of monthly sampling, we limited the trend analyses to the most recent 6 years of data. This is a relatively short period to base trend analysis on, and reflects inter-annual variability rather than long-term trends. Climate exerts considerable influence over water quality particularly at inter-annual time scales (2-6 years), as outlined in a study by Snelder and Fraser (2019). Because this trend analyses always involves periods in which climate is variable, attributing trends to causes will need to control for climate variation. Therefore attributing trends to causes is complex and the role of climate is significant and needs to be accounted for. The sensitivity of trends to the different time-period windows has implications for the reporting of trends as part of state of environment reporting. Snelder and Fraser (2019) point out that there will often be large fluctuations in the proportions of trends indicating improving or degrading conditions in adjacent reporting periods. Therefore, no conclusions on causality can be drawn from the trend results in this SOE report at this point. An in-depth analysis with trend results including longer-term datasets and climate and land use data will be done in a separate trends report.

It is inappropriate to compare trends when datasets cover a different time period. For this reporting, we adopted a 5 out of 6-year requirement, in which any datasets with samples from at least 5 years of time period between July 2012 and June 2018 were considered comparable.

In some reporting of trend analyses, adjustment of the results is made to accommodate variation in river flow. This is known as flow adjustment, and changes the trend analyses to a parametric approach which complicates the statistical approach required. Flow adjustment was not completed on data hosted by LAWA when undertaking trend analyses, and there currently is no industry standard for flow adjustment for trend analyses of water quality in New Zealand. For these reasons, no flow adjustment was undertaken for the trend analyses presented here.

To estimate the strength of trends over time, a Theil-Sen slope estimator was used. The non-parametric Theil-Sen slope estimator calculates the median slope amongst lines through all pairs of points in the dataset. This approach is effective at estimating the true slope in water quality data series because it is less sensitive to outliers.

The values derived from the Theil-Sen slope estimator are given as “Percent Annual Change” (PAC), which is the magnitude of the trend given as a percent of the median of observed values. A trend in PAC was considered meaningful if the PAC was greater than 1% per year. For some variables, such as black disc distance, an increase in observed values is improvement (i.e., we can see further in the water). For other variables such as phosphorus concentration, an increase in observed values represents a deterioration (i.e. there is more phosphorus in the water).

In all tables that present trend results, the changes are represented in bold when they are significant (i.e., p value is less than 0.05). Given a significant trend for a particular variable, the PAC is highlighted in blue if there was a significant improvement in the water quality variable, and highlighted in red if there was a significant deterioration in the water quality variable.

The full details of trend analyses are presented Appendix C and a summary of trend results is presented in the sections on water quality variables that follow.

Significant trend results for sites are only presented on maps within the body of the report when they contained 5 or more years of data. Results of trend analyses for sites that contain less than 5 years of data are included Appendix C, with the shorter time period shaded in grey.


1.8.3 Water quality guidelines Environmental guidelines are often used to describe the general state of a natural resource, even though they may not be directly applicable in a regulatory context.

Table 1-6 outlines several relevant ‘trigger values’ and suggested water quality limits that are included in graphical summaries throughout this document. The various trigger values, guidelines and limits are discussed in the following paragraphs.

ANZECC (2000) guidelines are used to indicate environmental conditions in “baseline” (essentially unaffected) or “pseudo-baseline” (lightly impacted) catchments (Davies-Colley, 2000). The ‘trigger’ values are based on water quality conditions taken from sites from the NIWA National River Water Quality Monitoring Network (NRWQMN) (Davies-Colley, 2000). The trigger values relate to 80th percentile or 20th percentile values for the data range taken from the NRWQMN.

In the development of ANZECC (2000) trigger values, Davies-Colley (2000) states: ‘[r]unning medians of water quality data measured in monitoring programmes may be compared with these trigger values. If the median value of a water quality variable for a particular site exceeds the trigger value, then it is intended to “trigger” a response on the part of water managers, which might be to initiate special sampling or carry out an investigation of reasons for the degraded water quality.’

The Biggs (2000) New Zealand periphyton guidelines are used nationally to set limits around periphyton biomass as well as identifying possible values for setting nutrient limits or targets to manage nuisance periphyton growth.

The Hickey (2013) Nitrate Toxicity Guidelines represent the most up-to-date assessment of ecosystem nitrate toxicity and provide guidance around nitrate concentration thresholds, both as annual median and annual concentration peaks (95th percentile) for managing nitrate toxicity risk.

Hay et al. (2006) identified several appropriate limits for the protection of trout fisheries in their report ‘Water quality guidelines to maintain trout fishery values’. The report was produced on behalf of Horizons Regional Council in the development of the One Plan.

The MfE and MoH (2003) ‘microbiological water quality guidelines for marine and freshwater areas’ are used extensively to assess ‘risk’ according to contact recreation and exposure to bacteria present in aquatic environments. The National Policy Statement for Freshwater Management (NPS-FM) (MfE, 2017) and proposed Essential Freshwater Package (MfE, 2019) provide some more recent national direction on limits and guidelines.

Table 1-7 lists attributes from the National Policy Statement for Freshwater Management 2014 (MfE, 2017) for DIN and DRP, nitrate and ammonia toxicity, and E.coli.


Table 1-6: Summary of relevant water quality guidelines for the TANK catchments. *5-year average annual maxima

Variable1 Trigger / Guideline Source

TN – ANZECC Lowland 0.614 mg/L ANZECC (2000)

TN – ANZECC Upland 0.295 mg/L ANZECC (2000)

TP – ANZECC Lowland 0.033 mg/L ANZECC (2000)

TP – ANZECC Upland 0.026 mg/L ANZECC (2000)

DIN – ANZECC Upland 0.444 mg/L ANZECC (2000)

DIN – Periphyton growth 20 day accrual < 0.295 mg/L Biggs (2000)

DIN – ANZECC Upland 0.167 mg/L ANZECC (2000)

DRP – Periphyton growth 20 day accrual < 0.010 mg/L Biggs (2000)

DRP – ANZECC Lowland 0.010 mg/L ANZECC (2000)

DRP – ANZECC Upland 0.009 mg/L ANZECC (2000)

NO3-N Toxicity 90% species protection < 3.8 mg/L Hickey (2013)



Clarity – contact recreation > 1.6 m ANZECC (2000)

Clarity – ‘Significant’ trout fishery > 3.5 m Hay et al. (2006)

Clarity – ‘Outstanding’ trout fishery > 5.0 m Hay et al. (2006)

Turbidity – ANZECC lowland ≤ 5.6 NTU ANZECC (2000)

Turbidity – ANZECC upland ≤ 4.1 NTU ANZECC (2000)

E. coli – Contact recreation (health) Red alert > 550 (CFU/100ml) MfE and MoH (2003)

E. coli – Contact recreation (health) Amber alert > 260 (CFU/100ml) MfE and MoH (2003)

Periphyton cover – ecological condition excellent <20% PeriWCC* Matheson et al. (2016)

Periphyton cover – ecological condition good <40% PeriWCC* Matheson et al. (2016)

Periphyton cover – ecological condition fair <55% PeriWCC* Matheson et al. (2016)

Periphyton cover – ecological condition poor ≥55% PeriWCC* Matheson et al. (2016)

Periphyton cover – contact recreation and aesthetics <30% PeriWCC* Matheson et al. (2016)

Habitat score - excellent (≥ 75th percentile) ≥ 75 Clapcott (2015)

Habitat score - good (≥ median) ≥ 63 Clapcott (2015)

Habitat score - fair (≥ 25th percentile) ≥ 47 Clapcott (2015)

Habitat score - poor (< 25th percentile) < 47 Clapcott (2015)

Macrophyte cross sectional area/volume (CAV) ≤ 50 % CAV* Matheson et al. (2016)

Macrophyte surface area (SA) ≤ 50 % SA* Matheson et al. (2016)

DO % Saturation – protection of trout fisheries > 80% (MfE, 1991); (HBRC, 2006a)

DO mg/L – minimum DO concentration > 6 mg/L ANZECC (1992) MCI – Excellent (clean water); ‘Outstanding’ trout

fishery ≥ 119 Stark and Maxted (2007); Hay et al.

(2006) MCI – Good (possible mild pollution); ‘Significant’ trout

fishery 100-119 Stark and Maxted (2007); Hay et al.

(2006) MCI – Fair (probable moderate pollution) 80-99 Stark and Maxted (2007); Hay et al.

(2006) MCI – Poor (probable severe pollution) ≤ 80 Stark and Maxted (2007); Hay et al.

(2006)


Table 1-7: Attributes from the National Policy Statement for Freshwater Management 2014. (MfE, 2017). Attribute Bands for DIN and DRP, nitrate and ammonia toxicity, and E.coli.

Attribute Band and Description Numeric Attribute State

DIN mg/L – Ecosystem Health Median 95th percentile

A band – DIN similar to natural condition, no adverse effects ≤ 0.24 ≤ 0.56

B band – minor DIN elevation, slight impact on ecological community > 0.24 and ≤ 0.5 > 0.56 and ≤ 1.1

C band – moderate DIN elevation, impact on ecological community > 0.5 and ≤ 1.0 > 1.1 and ≤ 2.05

D band – substantial DIN elevation, significant impact on ecological community > 1.0 > 2.05

DRP mg/L – Ecosystem Health Median 95th percentile

A band – DRP similar to natural condition, no adverse effects ≤ 0.006 ≤ 0.021

B band – minor DRP elevation, slight impact on ecological community > 0.006 and ≤ 0.01 > 0.021 and ≤ 0.03

C band – moderate DRP elevation, impact on ecological community > 0.01 and ≤ 0.018 > 0.03 and ≤ 0.054

D band – substantial DRP elevation, significant impact on ecological community > 0.018 > 0.054

NH4-N mg/L – Ecosystem Health (Ammonia Toxicity) Annual Median Annual Maximum

A band – 99% species protection level: no observed effect on any species tested ≤ 0.03 ≤ 0.05

B band – 95% SPL: occasional impact on 5% most sensitive species > 0.03 and ≤ 0.24 > 0.05 and ≤ 0.4

C band – 80% SPL: regular impact on 20% most sensitive species, reduced survival > 0.24 and ≤ 1.3 > 0.4 and ≤ 2.2

D band – approaches acute impact level (i.e. risk of death) for sensitive species > 1.3 > 2.2

NO3-N mg/L – Ecosystem Health (Nitrate Toxicity) Annual Median Annual 95th prctl

A band – high conservation value system, unlikely to be effects ≤ 1.0 ≤ 1.5

B band – some growth effects on up to 5% of species > 1.0 and ≤ 2.4 > 1.5 and ≤ 3.5

C band – growth effects on up to 20% mainly sensitive species. No acute effects > 2.4 and ≤ 6.9 > 3.5 and ≤ 9.8

D band – impact on growth of multiple species, approaches acute impact level > 6.9 > 9.8


Table 1-7 continued

Attribute Band and Description Numeric Attribute State

Risk of Campylobacter infection (based on E.coli indicator) (Human contact, Human Health)

% exceedances over 540

E.coli/100mL

% exceedances over 260

E.coli/100mL

Median concentration E.coli/100mL

95th percentile of E.coli/100mL

A band – (blue) For at least half the time, the estimated risk is <1 in 1000 (0.1% risk) The predicted average infection risk is 1%

<5% <20% ≤130 ≤540

B band – (green) For at least half the time, the estimated risk is <1 in 1000 (0.1% risk) The predicted average infection risk is 2%*

5-10% 20-30% ≤130 ≤1000

C band – (yellow) For at least half the time, the estimated risk is <1 in 1000 (0.1% risk) The predicted average infection risk is 3%*

10-20% 20-34% ≤130 ≤1200

D band – (orange) 20-30% of the time the estimated risk is ≥50 in 1000 (>5% risk) The predicted average infection risk is >3%*

20-30% >34% >130 >1200

E band – (red) For more than 30% of the time the estimated risk is ≥50 in 1000 (>5% risk) The predicted average infection risk is >7%*

>30% >50% >260 >1200


Box plots have been used throughout Chapter 2 to summarise water quality data. The sites are ordered from left to right in an upstream to downstream order along the river channel. Sites are grouped by their position in the same major sub-catchment. For example, the Poporangi stream is a tributary to the Ngaruroro and is located further upstream than the Maraekakaho Stream, so the Poporangi SOE site appears to the left of the Maraekakaho SOE site in the graph.

Catchment maps have been used to spatially represent changes in water quality data based on the median value of observations taken over the last 5 years for the water quality variable in question. The catchment maps include arrows indicating the direction of statistically significant trends, with blue arrows for improvement and red arrows for deterioration of the variable in question. Sites without an arrow did not exhibit a statistically significant trend.

Tables of summary statistics are presented in Appendix A for the Ngaruroro and Tūtaekurī catchments and in Appendix B for the Karamū and Ahuriri catchments to provide additional context to the changes in water quality variables under differing flow conditions. For example, the levels of faecal bacteria in rivers during high flows may not be relevant for bathing, because people will not be swimming during high flows. The conditions most likely to be experienced by bathers can be found in the < Lower Quartile Flow table (i.e. low flows).

Box plots, catchment water quality summary maps and statistical summaries of water quality variables all use the last 5 years of data to best represent current conditions throughout the catchment. Data obtained from sites during all flow conditions was used for these comparisons.

The median values for each variable are also placed in comparison with median values from all sites in Hawke’s Bay, and presented as rank tables in Appendix D. This facilitates a comparison of water quality variables, as well as how the collection of sites in a reporting zone compares with other reporting zones.


KEY POINT: Box plots graph data as a box representing statistical values. The boundary of the box closest to zero indicates the 25th percentile, a line within the box marks the median, and the boundary of the box farthest from zero indicates the 75th percentile. Whiskers (error bars) above and below the box indicate the 90th and 10th percentiles.


2 Water Quality in the Ngaruroro and Tūtaekurī River Catchments: Long-term SOE data

2.1 Nutrients Nitrogen (N) and phosphorus (P) are key ‘growth limiting’ nutrients that influence the growth rate and extent of algae (or periphyton) and aquatic plants. A deficit in the supply of one or both of these two nutrients often limits plant biomass development (Matheson et al., 2012).

Eutrophication is the term used to describe the enrichment of water bodies by inorganic plant nutrients such as nitrate or phosphate. Eutrophication may occur naturally over geological timescales, particularly in lakes, and in rivers eutrophication increases on an upstream to downstream gradient, but higher levels of enrichment are commonly the result of human activity. Land-use change and intensification often give rise to elevated levels of nitrogen and phosphorus, particularly in areas where appropriate farming practices are not followed. Nuisance periphyton growth can be managed by reducing or eliminating inputs of N and P from point-source discharges and/or diffuse sources such as discharges from productive land-use (Biggs, 2000).

KEY POINT: Dissolved Inorganic Nitrogen (DIN) and Dissolved Reactive Phosphorus (DRP) are dissolved inorganic forms of the nutrients nitrogen (N) and phosphorus (P) respectively. N and P are the two key macronutrients required for growth of plants and algae, occurring in all living cells – for example being key elements in proteins and DNA. DIN includes nitrate, nitrite and ammonia. DRP includes phosphate. Although numerous other forms of nitrogen and phosphorus exist and are commonly referred to in the field of water quality (e.g. organic and particulate forms), it is the dissolved forms DIN and DRP that are most readily available for uptake by plants and are thus most relevant for assessing effects on nuisance plant growth in rivers. The terms total nitrogen (TN) and total phosphorus (TP) refer to the sum total of all forms of N and P respectively in a sample. TN and TP are most relevant for assessments in lakes and coastal waters. At sufficiently elevated concentrations, nitrate and ammonia forms of nitrogen have toxic effects on aquatic biota (and on humans in the case of nitrate). This effect is independent of their significance as plant nutrients (Norton, 2012).

2.1.1 Total Nitrogen (TN) and Total Phosphorus (TP)

TN and TP highlights in the Ngaruroro and Tūtaekurī catchments

• TN and TP concentrations are low in the main stems of the Ngaruroro and Tūtaekurī Rivers, but gradually increase towards the sea.

• TN and TP in tributaries are higher and above ANZECC trigger levels at some sites.

• TN and TP are lowest (best) regionally at upper catchment sites Kuripapango, Whanawhana and Lawrence Hut.

• TN or TP increased at several sites over the 6 year period, these trends need further investigation.


Figure 2-1 and Figure 2-2 are box-plots of total nitrogen (TN) and total phosphorus (TP) concentration for SOE monitoring sites across the Ngaruroro and Tūtaekurī catchments. ANZECC trigger levels have been included on the plots for upland (> 150m altitude) and lowland sites (< 150m altitude). Upland sites are Ngaruroro River at Kuripapango, and Tūtaekurī River at Lawrence Hut. All other sites are lowland sites according to ANZECC guidelines.

TN concentrations in the mainstem of the Ngaruroro River stayed well below lowland ANZECC trigger values (Figure 2-1). There was a gradual increase in TN concentrations from upstream to downstream, but the TN concentration levels remained generally very low, even below the more stringent ANZECC upland trigger value over the entire length of the mainstem. Some of the tributaries had high TN concentrations, particularly the Poporangi, Ohiwia and Maraekakaho streams (Figure 2-3).

TN concentrations in the Tūtaekurī mainstem increased from Lawrence Hut to Brookfields Bridge, but TN was below the lowland ANZECC trigger value at all sites in the mainstem. The Mangatutu Stream and the Mangaone River had higher TN concentrations, but were mostly below ANZECC lowland trigger levels.

The Ngaruroro at Kuripapango has the lowest TN concentration of the region, ranking in first place, and even the most downstream site in the mainstem, at Chesterhope, has low TN concentrations and ranks 11th best. The Tūtaekurī at Lawrence Hut ranks equal second with the Ngaruroro at Whanawhana. Tūtaekurī at Brookfields Bridge ranks 24th place, still within the better third of sites regionally. Most tributaries of both the Ngaruroro and Tūtaekurī catchments have high TN concentrations, and are among the half of the region’s SOE sites with higher concentrations, ranking between 43rd and 54th place.


Figure 2-1: Total nitrogen (TN) levels at Ngaruroro and Tūtaekurī SOE sites. The blue line is ANZECC (2000) ‘Upland’ TN trigger value; the red line to ANZECC (2000) ‘Lowland’ TN trigger value. Ngaruroro at Kuripapango and Tūtaekurī at Lawrence Hut are upland sites. All other sites are lowland according to ANZECC guidelines. SOE sites for the Mohaka River U/S Taharua confluence and the Ngaruroro River at Whanawhana (shaded) are included as Upland (U) and Lowland (L) reference sites for comparison.

TP concentration in the Ngaruroro mainstem increased towards the sea in a similar way as TN, and was also below ANZECC trigger levels along the river (Figure 2-2). Except for the Ohara Stream, all tributaries showed elevated levels of TP. Particularly high concentrations were measured in the Ohiwa (Figure 2-4). In the Tūtaekurī-Waimate the TP concentration was above the lowland ANZECC trigger level in most of the samples.


Figure 2-2: Total phosphorus (TP) levels at Ngaruroro and Tūtaekurī River SOE sites. The blue line is ANZECC (2000) ‘Upland’ TP trigger value; the red line to ANZECC (2000) ‘Lowland’ TP trigger value. Ngaruroro at Kuripapango and Tūtaekurī at Lawrence Hut are upland sites. All other sites are lowland according to ANZECC guidelines. SOE sites for the Mohaka River U/S Taharua confluence and the Ngaruroro River at Whanawhana (shaded) are included as Upland (U) and Lowland (L) reference sites for comparison.


Figure 2-3: 5 year median TN levels at Ngaruroro and Tūtaekurī SOE sites including trend direction. Arrows indicate direction of significant trends, with blue arrows for improvement and red arrows for deterioration. 6 years of record between 2012 and 2018 for trend analysis.


Figure 2-4: 5 year median TP levels at Ngaruroro and Tūtaekurī SOE sites including trend direction. Arrows indicate direction of significant trends, with blue arrows for improvement and red arrows for deterioration. 6 years of record between 2012 and 2018 for trend analysis.


The 6-year trend analysis (Table 2-1) indicated significantly increasing TN trends at 4 sites in the Tūtaekurī catchment: in the Mangatutu Stream, the Mangaone River, and in the Tūtaekurī mainstem upstream of the Mangaone confluence and at Brookfields Bridge, which is at the bottom of the catchment. TP increased significantly in the Ngaruroro River downstream HB Dairies, which is also the case for DRP (Table 2-2). Trend results of the current reporting period contrast with results from last reporting period (2004 to 2012) which had decreasing TN and TP at 5 sites in the Ngaruroro and Tūtaekurī catchments. Climate exerts considerable influence over water quality at inter-annual time scales (2-6 years) (Snelder and Fraser, 2019). Trend analysis started 2012, with a year that featured a drought that was significant both regionally and nationally. For three of the first four years, rainfall was lower than average. For the last two years of trend analysis, 2017 and 2018, rainfall was higher than average. In particular, the area around the Mangaone River suffered a severe storm and localised flooding in the last year of trend analysis, the rainfall total had a return period in excess of 100 years. An in-depth analysis with trend results including longer-term datasets and climate and land use data will be done in a separate trends report.

Table 2-1: Trend analysis results for TN and TP at Ngaruroro and Tūtaekurī SOE sites period 2012 to 2018. Includes only sites with sufficient data and monitoring length for trend analysis. In bold: significant trend when p < 0.05. Cells shaded blue for improving trend, red for deteriorating trend.

Site

Total Nitrogen Total Phosphorus

Median P value Per cent Annual Change

Med. ian P value

Per cent Annual Change

Ngaruroro Rv at Kuripapango (NIWA) 0.046 0.411 2.432 0.004 0.375 0 Ngaruroro Rv at Whanawhana 0.055 0.34 0 0.002 0.10 0 Ohara Strm 0.175 0.05 36.235 0.009 0.49 23.582 Poporangi Strm 0.7 0.243 2.884 0.032 0.063 3.469 Ngaruroro Rv D⁄S HB Dairies 0.13 0.32 0.849 0.009 0.05 10.883 Maraekakaho Strm 0.465 0.9 -0.592 0.026 0.65 0.988 Waitio Strm 0.3 0.27 2.214 0.03 0.56 -2.155 Ohiwa Strm 0.665 0.26 6.028 0.123 0.28 3.683 Ngaruroro Rv at Fernhill 0.175 0.18 3.314 0.012 0.16 6.468 Tūtaekurī-Waimate Strm 0.372 0.34 3.287 0.04 0.54 1.872 Ngaruroro Rv at Chesterhope (NIWA) 0.143 0.087 -7.818 0.02 0.485 -3.077 Tūtaekurī Rv at Lawrence Hut 0.055 0.12 0 0.005 0.16 5.014 Mangatutu Strm 0.56 0.000 8.79 0.025 0.122 3.008 Tūtaekurī Rv U/S Mangaone 0.24 0.004 9.566 0.017 0.058 5.694 Mangaone Rv at Rissington 0.46 0.004 7.737 0.033 0.07 3.079 Tūtaekurī Rv at Brookfields Br 0.276 0.003 8.815 0.026 0.09 5.223


2.1.2 Dissolved Inorganic Nitrogen (DIN) and Dissolved Reactive Phosphorus (DRP)

Figure 2-5 and Figure 2-7 are box-plots of dissolved inorganic nitrogen (DIN) and dissolved reactive phosphorus (DRP) concentrations for SOE monitoring sites across the Ngaruroro and Tūtaekurī catchments. Upland sites are the Ngaruroro River at Kuripapango and the Tūtaekurī River at Lawrence Hut. All other sites are considered lowland sites according to ANZECC guidelines. Median DIN and DRP concentrations at SOE sampling sites in the Ngaruroro and Tutaekuri catchments are shown on maps in Figure 2-9 and Figure 2-10.

As discussed in the ‘Key Note’ at the start of Chapter 2.1, DIN and DRP are important because they represent the two most significant nutrients that stimulate or limit periphyton growth, since they are immediately ‘bioavailable’ to algae and plants for growth. By comparison, some forms of nitrogen and phosphorus, such as organic nitrogen and particulate phosphorus, are not immediately available to algae and plants and need to go through decomposition processes such as re-mineralisation to be turned into bioavailable forms.

Increases in DIN and DRP can lead to increased periphyton growth and eutrophication of a waterway. Nuisance algal growth is more likely during long periods of low flow and in river reaches with high light availability. As a result, guidelines for nutrient concentrations are used as a proxy for keeping periphyton growth at acceptable levels.

DIN concentrations in the Ngaruroro mainstem increased from upstream to downstream, but remained at very low concentrations and always well below lowland ANZECC trigger values and the periphyton 20-day accrual guideline. DIN concentrations in the tributaries were higher than in the mainstem, and the median concentration in Poporangi and Ohiwa streams was above lowland ANZECC trigger values and exceeded the periphyton 20-day accrual guideline. DIN concentrations in the Maraekakaho Stream were variable, often above lowland trigger values, but the median concentration was below the 20-day periphyton accrual guideline. The Ohara Stream is a tributary to the Poporangi, and was measured for 3 years since 2015. The Ohara Stream had the lowest DIN concentration of any monitored tributary in the Ngaruroro and Tūtaekurī catchments.

DIN concentrations in the upper Tūtaekurī at Lawrence Hut were very low, comparable to levels at reference

DIN and DRP highlights in the Ngaruroro and Tūtaekurī catchments

• DIN concentrations were low in the mainstems of Ngaruroro and the Tūtaekurī, but gradually increased towards the sea.

• DIN in tributaries were higher and above ANZECC trigger levels and periphyton accrual guidelines at some sites.

• DRP concentrations increase in the mainstems from upstream to downstream, particularly in the Tūtaekurī: the mid and lower sites were well above ANZECC trigger levels.

• DRP concentrations in the tributaries of both catchments always exceeded ANZECC trigger levels at all sites except one.

• DIN and DRP decreased at some sites and increased at others over a 6-year period. This needs further investigation.


conditions in the upper Mohaka and Ngaruroro. DIN increased in the middle to lower Tūtaekurī reaches but remained generally below the lowland ANZECC trigger value and periphyton 20-day accrual guideline. DIN concentrations in the Tūtaekurī tributaries were generally higher than in the mainstem. The median DIN concentration in the Mangatutu Stream was at the lowland ANZECC trigger value, and was below the trigger value in the Mangaone River.

Figure 2-5: DIN concentrations at Ngaruroro and Tūtaekurī SOE sites. The blue line is (ANZECC, 2000) ‘Upland’ TN trigger value; the red line to (ANZECC, 2000) ‘Lowland’ TN trigger value, the orange line is the periphyton 20 day accrual guideline (Biggs 2000). The sites Ngaruroro at Kuripapango and Tūtaekurī at Lawrence Hut are upland sites. All others are lowland sites according to ANZECC guidelines. SOE sites for the Mohaka River U/S Taharua confluence and the Ngaruroro River at Whanawhana (shaded) are included as Upland (U) and Lowland (L) reference sites for comparison.

New attributes in the draft document Action for Healthy Waterways suggest 4 bands for DIN and DRP in rivers (MfE, 2019). Ngaruroro and Tūtaekurī catchment data compared to the proposed thresholds are shown in Figure 2-6 and Figure 2-8.

All mainstem Ngaruroro sites have median DIN concentrations similar to natural levels (Figure 2-6). The median DIN concentration in the tributaries range from band A (Ohara Stream) to band C (Poporangi Stream, which is adjacent to the Ohara Stream). Band C indicates moderate DIN elevation, and if other conditions


favour eutrophication, DIN enrichment may cause increased algal and plant growth, loss of sensitive macroinvertebrate and fish taxa, and high rates of respiration and decay.

Figure 2-6: DIN concentrations at Ngaruroro and Tūtaekurī SOE sites in relation to proposed NOF DIN attribute bands (MfE, 2019). Below blue line: Band A, similar to natural reference condition. Between blue and green line: Band B, minor DIN elevation, slight impact on ecological community. Between green and red line: Band C, moderate DIN elevation, impact on ecological community. Above red line: Band D, substantial DIN elevation, significant impact on ecological community. The sites Ngaruroro at Kuripapango and Tūtaekurī at Lawrence Hut are upland sites. All others are lowland sites according to ANZECC guidelines. SOE sites for the Mohaka River U/S Taharua confluence and the Ngaruroro River at Whanawhana (shaded) are included as Upland (U) and Lowland (L) reference sites for comparison.

DRP concentrations followed a similar pattern to the TP concentrations in the Ngaruroro catchment: DRP in the Ngaruroro mainstem increased towards the sea but remained at low concentrations, generally below ANZECC trigger levels. All tributaries except the Ohara Stream had high DRP concentrations, and always exceeded the lowland trigger levels. The Ohiwa Stream, a short term study site, showed particularly high levels of DRP concentration with a median concentration of 0.117 mg/L, more than 10 times higher than ANZECC trigger value. In the Tūtaekurī catchment the DRP concentration was very low at the near pristine site at Lawrence Hut and increased to median concentrations that were above ANZECC lowland trigger value


from the mid catchment (upstream of the Mangaone River confluence) to the sea. DRP concentrations in the tributaries Mangatutu and Mangaone always exceeded ANZECC trigger values.

Figure 2-7: Dissolved reactive phosphorus (DRP) levels at Ngaruroro and Tūtaekurī SOE sites. The blue line is (ANZECC, 2000) ‘Upland’ DRP trigger value, the red line to (ANZECC, 2000) ‘Lowland’ DRP trigger value and the Biggs (2000) suggested limit for DRP for periphyton growth management for a 20 day accrual period. The sites Ngaruroro at Kuripapango and Tūtaekurī at Lawrence Hut are upland sites. All other sites are lowland according to ANZECC guidelines. SOE sites for the Mohaka River U/S Taharua confluence and the Ngaruroro River at Whanawhana (shaded) are included as Upland (U) and Lowland (L) reference sites for comparison.

Compared to the proposed attribute bands in the draft document Action for Healthy Waterways (MfE, 2019) the upper and mid mainstem Ngaruroro sites (at Kuripapango , Whanawhana and downstream of HB Dairies) were in band A, and in band B at Fernhill and Chesterhope (Figure 2-8). Band B indicates that there is a minor DRP elevation above reference conditions that could have a slight impact on aquatic communities if other conditions (e.g. DIN concentration) favour eutrophication. Median DRP concentrations of the tributary sites (except for the Ohara Stream) fell into band D, where DRP is substantially elevated above natural conditions, and eutrophication can cause excessive algal and plant growth, significant changes in macroinvertebrate and fish communities, as taxa sensitive to hypoxia are lost.


Figure 2-8: DRP concentrations at Ngaruroro and Tūtaekurī SOE sites in relation to proposed NOF DIN attribute bands (MfE, 2019). Below blue line: Band A, similar to natural reference condition. Between blue and green line: Band B, minor DIN elevation, slight impact on ecological community. Between green and red line: Band C, moderate DIN elevation, impact on ecological community. Above red line: Band D, substantial DIN elevation, significant impact on ecological community. The sites Ngaruroro at Kuripapango and Tūtaekurī at Lawrence Hut are upland sites. All others are lowland sites according to ANZECC guidelines. SOE sites for the Mohaka River U/S Taharua confluence and the Ngaruroro River at Whanawhana (shaded) are included as Upland (U) and Lowland (L) reference sites for comparison.

Total and dissolved nutrient concentrations increase in the mainstem of the Ngaruroro and Tūtaekurī from upstream to downstream towards the sea, which reflects the contribution of nutrients from the tributaries. This increase in concentrations is lower in the Ngaruroro than in the Tūtaekurī. Compared to the Tūtaekurī, the Ngaruroro has a larger area in native vegetation cover, and therefore a higher volume of pristine low-nutrient water from the mountains, diluting the nutrient input from the tributaries.

Table 2-2 summarises the results of 6-year trend analysis between July 2013 and June 2018 carried out on DIN and DRP concentration across SOE monitoring sites in the Ngaruroro and Tūtaekurī river catchments. For a full summary of trend analysis results refer to Appendix C. DIN in the Maraekakaho Stream and in the Tūtaekurī at Lawrence Hut decreased significantly over the 6-year period.


DRP increased significantly over 6 years in the mid main-stem of both, the mid Ngaruroro and mid Tūtaekurī rivers.

As already discussed in relation to trends in TP and TN concentrations, climate could be a driver for the observed trends, and an in-depth analysis with trend results including longer-term datasets and climate and land use data will be done in a separate trends report. Trend analysis started in a significant drought year (2012), and in the following years rainfall was lower than average. For the last two years of the trend analysis, rainfall was higher than average with severe storms and localised flooding. The rainfall total had a return period in excess of 100 years in the Mangaone River area.

Table 2-2: Trend analysis results for DIN and DRP at Ngaruroro and Tūtaekurī SOE sites period 2012 to 2018. Includes only sites with sufficient data and monitoring length for trend analysis. In bold: significant trend when p < 0.05. Cells shaded blue for improving trend, red for deteriorating trend.

Site

DIN DRP



Ngaruroro Rv at Kuripapango (NIWA) 0.010 0.087 10.087 0.002 0.646 1.374 Ngaruroro Rv at Whanawhana 0.003 0.810 0.000 0.002 0.660 0.000 Ohara Strm* NA NA NA NA NA NA Poporangi Strm 0.531 0.723 0.990 0.026 0.090 2.425 Maraekakaho Strm 0.224 0.050 -8.807 0.023 0.660 3.244 Ngaruroro Rv D/S HB Dairies 0.086 0.210 4.129 0.005 0.000 7.865 Waitio Strm 0.212 0.130 4.120 0.023 0.910 0.325 Ohiwa Strm 0.468 0.190 2.236 0.113 0.110 6.621 Ngaruroro Rv at Fernhill 0.110 0.490 2.685 0.008 0.170 7.513 Tūtaekurī-Waimate Strm 0.243 1.000 0.000 0.031 0.660 1.071 Ngaruroro Rv at Chesterhope (NIWA) 0.082 0.171 -9.249 0.007 0.286 -3.581 Tūtaekurī Rv at Lawrence Hut 0.016 0.020 -3.081 0.004 0.170 0.000 Mangatutu Strm 0.389 0.020 9.427 0.020 0.240 1.657 Tūtaekurī Rv U/S Mangaone 0.159 0.290 0.620 0.014 0.050 4.042 Mangaone Rv at Rissington 0.338 0.090 6.674 0.026 0.100 3.907 Tūtaekurī Rv at Brookfields Br 0.168 0.350 0.302 0.020 0.110 4.969


Figure 2-9: 5 year median DIN levels at Ngaruroro and Tūtaekurī SOE sites including trend direction. Arrows indicate direction of significant trends, with blue arrows for improvement and red arrows for deterioration. 6 years of record between 2012 and 2018 for trend analysis.


Figure 2-10: 5 year median DRP levels at Ngaruroro and Tūtaekurī SOE sites including trend direction. Arrows indicate direction of significant trends, with blue arrows for improvement and red arrows for deterioration. 6 years of record between 2012 and 2018 for trend analysis.


2.2 Nitrate-nitrogen and ammonia-nitrogen toxicity

The NPS-FM (MfE, 2017) requires councils to set a freshwater objective for nitrate and ammonia in all rivers.

DIN, as discussed in Chapter 2.1.2, includes nitrate-nitrogen (NO3-N), nitrite-nitrogen (NO2-N) and ammoniacal-nitrogen (NH4-N). Nitrate-nitrogen is the dominant component of DIN in areas not directly affected by point-source discharges and in catchments without large areas of wetlands with anoxic soils. Generally, nitrate concentrations are managed at considerably lower than toxic levels to achieve periphyton objectives using the DIN attribute.

Nitrate and ammonia are toxicants that can cause lethal or sub-lethal (e.g. reduced growth rates or reproductive success) effects to aquatic species. These effects can occur as a result of short-term (hours to days) or long-term (weeks, months, years) exposure to nitrate or ammonia.

In the Guide to Attributes report (MfE, 2018) toxicity attributes of the NPS-FM are explained in the following way:

The NPS-FM defines nitrate and ammonia toxicity attribute states based on concentrations that protect a specific percentage of test species from long-term exposure to nitrate. The national bottom line is set at nitrate concentrations that provide protection from effects of long-term exposure for 80 per cent of species. The higher attribute states provide for protection from effects of long-term exposure for 95 per cent to 99 per cent of species. All of the Freshwater NPS nitrate toxicity attribute states protect 100 per cent of test species from effects of short-term exposure.

The first set of attribute state thresholds (i.e. median concentration) are set at the ‘No Observed Effect Concentration’ (NOEC) for each level of species protection. The second set of attribute state thresholds (i.e. 95th percentile and maximum) are set at the ‘Threshold Effect Concentration’ (TEC) for each level of species protection, which can be interpreted as below the level of an effect.

Each set of thresholds is associated with a particular sample statistic to reflect different timescales of effect:

Nitrate-nitrogen and ammonia-nitrogen highlights in the Ngaruroro and Tūtaekurī catchments

• Ammonia and nitrate toxicity risks are minimal in both the Ngaruroro and Tūtaekurī catchments.

• At all sites, species protection is in the NOF A Band (99% species protection level) under average conditions for both ammonia and nitrogen.

• At most sites, species protection was in the NOF A Band, regarding the toxicity effects of short-term peaks and critical events.

• Nitrate peaks occurred in the Maraekakaho and Tutaekuri-Waimate streams, ammonia peaks occurred in the Mangaone and Mangatutu, in the mid-Tūtaekurī River, and in the Ohiwa (Ngaruroro catchment).

• Over the last 6 years, nitrate concentration decreased in the Maraekakaho Stream, and increased in the Mangatutu Stream.


• NOEC and a sample median manages exposure under ‘average’ conditions in nitrate and ammonia concentrations.

• TEC and a 95th percentile manages exposure during seasonal peaks in nitrate concentrations.

• TEC and a maximum manage exposure during critical events and daily or seasonal peaks in ammonia concentrations.

The toxicant effects of ammonia come from the un-ionised form, while the numeric attribute states are defined for (total) ammoniacal nitrogen. Temperature and pH have a significant effect on the fraction of un-ionised ammonia and its toxicity, so the numeric attribute states, and therefore freshwater objectives, are defined for a pH of 8 and temperature of 20oC.

NPS-FM bands for nitrate and ammonia toxicity are in Appendix E.

2.2.1 Nitrate-nitrogen toxicity Table 2-3 summarises nitrate-nitrogen and ammonia-nitrogen toxicity bands for the Tūtaekurī and Ngaruroro catchments. Median nitrate-nitrogen concentrations were in the A band for all sites in the Ngaruroro and Tūtaekurī catchments. The sample median in band A reflects a low level of risk from nitrate toxicity to any aquatic species under average conditions.

There are higher and more variable nitrate concentrations in the Ngaruroro tributaries, especially the Poporangi, Maraekakaho, Ohiwa and Tūtaekurī-Waimate streams. The 95th percentile nitrate-nitrogen concentrations were in the A band for most sites. Only the Maraekakaho and the Tūtaekurī-Waimate streams in the Ngaruroro catchment were in the B and C band, respectively. In the Maraekakaho Stream nitrate concentrations exceeded the threshold for the B Band (1.5 mg/L) in 2013 and 2016 with 95th percentile concentrations of 2.7 mg/L and 1.86 mg/L respectively (year to year median and 95th percentile statistics in Appendix F). Band B means that some growth effect on up to 5% of species may occur during these seasonal peaks in nitrate concentrations. The Tūtaekurī-Waimate fell into the B band in 2016 with a 95th percentile of 2.3 mg/L and into the C band in 2017 with 4.225 mg/L (Appendix F). The C band indicates there may be some growth effect on up to 20% of species, mainly sensitive species, but there should be no acute effects (Appendix E).


Table 2-3: NPS-FM (2014) NOF band summary for nitrate-nitrogen and ammonia-nitrogen at Tūtaekurī and Ngaruroro SOE sites for the period 2013 to 2018. *Ohara Strm has data record of 3 years only.

Site

Nitrate (toxicity) Ammonia (toxicity)

Median 95th percentile Median Maximum

Ngaruroro at Kuripapango (NIWA) ND ND A A Ngaruroro Rv at Whanawhana A A A A Ohara Strm * A A A A Poporangi Strm A A A A Maraekakaho Strm A B A A Ngaruroro D/S HB Dairies A A A A Waitio Strm A A A A Ohiwa Strm A A A B Ngaruroro Rv at Fernhill A A A A Tūtaekurī-Waimate Strm A C A A Ngaruroro at Chesterhope (NIWA) ND ND A A Tūtaekurī Rv at Lawrence Hut A A A A Mangatutu Strm A A A B Tūtaekurī Rv U/S Mangaone Rv A A A C Mangaone Rv at Rissington A A A B Tūtaekurī Rv at Brookfields Br A A A A

The distribution of nitrate-nitrogen concentration data in relation to the 99% species protection is shown in Figure 2-11, and Figure 2-12 shows a map of 5-year median concentrations at the SOE sites. The nitrate-nitrogen concentration was always well below the 99% species protection level at all sites in the Tūtaekurī catchment. In the Maraekakaho and Tūtaekurī-Waimate Streams nitrate concentrations were more variable: under normal conditions nitrate toxicity was within the Band A, i.e. 99% species protection (median line in boxes in Figure 2-11), but some samples were elevated (whiskers in Figure 2-11), which shows occasional peak concentrations may have some effect on sensitive species.

Median 5-year nitrate-nitrogen concentrations at SOE sites in the Ngaruroro and Tutaekuri catchments are shown in a map in Figure 2-11.


Figure 2-11: Nitrate - nitrogen (NO3-N) levels at Ngaruroro and Tūtaekurī SOE sites. The blue lines are the NPS-FM NOF nitrate toxicity threshold for the A Band for 99% species protection: ‘High conservation value systems. Unlikely to be effects even on sensitive species’. The blue line is related to the annual median at the sites (the line in the blue boxes). Whiskers are indicating the 95th percentile. Sites marked with * are short-term monitoring sites (data records less than 5 years). SOE sites for the Mohaka River U/S Taharua confluence and the Ngaruroro River at Whanawhana (shaded) are included as Upland (U) and Lowland (L) reference sites for comparison.

The 6-year trend analysis (Table 2-4) indicated a significantly decreasing nitrate-nitrogen trend in the Maraekakaho Stream, and an increasing trend in the Mangatutu Stream.


Table 2-4: Trend analysis results for nitrate-nitrogen (NO3-N) at Ngaruroro and Tūtaekurī SOE sites period 2012 to 2018. Includes only sites with sufficient data for trend analysis. In bold: significant trend when p < 0.05. Cells shaded blue for improving trend, red for deteriorating trend.

Site

Nitrate


Ngaruroro Rv at Kuripapango (NIWA) NA NA NA Ngaruroro Rv at Whanawhana 0.018 0.290 4.836 Ohara Strm* NA NA NA Poporangi Strm 0.530 0.773 0.787 Maraekakaho Strm 0.215 0.050 -9.456 Ngaruroro Rv D/S HB Dairies 0.076 0.240 5.368 Waitio Strm 0.210 0.230 4.756 Ohiwa Strm 0.395 0.180 3.007 Ngaruroro Rv at Fernhill 0.091 0.290 3.245 Tūtaekurī-Waimate Strm 0.220 0.830 0.513 Ngaruroro Rv at Chesterhope (NIWA) NA NA NA Tūtaekurī Rv at Lawrence Hut 0.006 0.860 -0.828 Mangatutu Strm 0.380 0.010 10.590 Tūtaekurī Rv U/S Mangaone 0.163 0.070 2.132 Mangaone Rv at Rissington 0.330 0.110 6.292 Tūtaekurī Rv at Brookfields Br 0.157 0.340 0.846


Figure 2-12: 5 year median NO3-N levels at Ngaruroro and Tūtaekurī SOE sites including trend direction. Arrows indicate direction of significant trends, with blue arrows for improvement and red arrows for deterioration. 6 years of record between 2012 and 2018 for trend analysis.


2.2.2 Ammonia toxicity The annual median concentration of ammonia reflects the exposure of aquatic species under average conditions while the maximum concentration manages the exposure during critical events and daily or seasonal peaks in ammonia concentration.

Median ammonia concentrations for all monitoring sites in the Ngaruroro and Tūtaekurī catchments were in the A band over the 5-year period (Table 2-3), and in each year from 2014 to 2018 (Appendix F), reflecting minimum risk for toxicity under average conditions.

When considering annual maxima most sites had an A grading in the Ngaruroro and Tūtaekurī catchments. Three sites were in the B band: Ohiwa Stream (Ngaruroro catchment), the Mangatutu Stream and Mangaone River (Tūtaekurī catchment). The Tūtaekurī River upstream of the Mangaone confluence was in the C band.

Looking at year to year bands (Appendix F), the three Tūtaekurī sites were generally in the A-band over the 5-year reporting period. In 2014 all three Tūtaekurī sites exceeded and fell into the B/C band. The Mangatutu exceeded the A/B threshold a second time in 2016, but in both years the ammonia-nitrogen concentration was just marginally exceeding into the B band with concentrations of 0.052 and 0.06 mg/L: the B band lies between the thresholds of 0.05 mg/L and 0.4 mg/L annual maximum ammoniacal-nitrogen. The same happened in the Ohiwa Stream in the Ngaruroro catchment: it was generally in the A band, but exceeded the A/B threshold in 2016 with a maximum of 0.066mg/L, just above the threshold.

In summary the results indicate that nitrate and ammonia toxicity meets 99% species protection level under average conditions in the Ngaruroro and Tūtaekurī catchments at all sites. In most years this protection level is also met under extreme conditions, but in few years samples exceeded over the 5 years.


2.3 Water Clarity – Black disc and turbidity

Fine sediment is defined as particles < 2 mm and consists of sediment commonly called sand, silt and mud. It originates naturally from weathered rock (by wind, water, ice), gets into waterways and is transported until it is eventually deposited. Human activities accelerate the delivery of sediment to streams and increase the quantity of fine particles in the water. This leads to decreased water clarity and increased turbidity, and sediment is deposited on stream beds and estuaries.

Water clarity refers to light transmission through water, and has 2 important aspects: visual clarity (sighting range for humans and aquatic animals), and light penetration for growth of aquatic plants (Davies-Colley et al., 2003, Davies-Colley and Smith, 2001).

Water clarity is important for the protection of contact recreation values, because it directly affects the water’s aesthetic quality for recreational users. In addition, adequate visual clarity allows swimmers to estimate depth and identify subsurface hazards (ANZECC, 2000). Trout hunt visually and drift feeding is their main foraging behaviour in most rivers (Hay et al., 2006). Reduced visual clarity (or equivalent increases in water turbidity) reduces foraging efficiency (i.e. more energy is spent consuming the same amount of prey, or fewer prey are consumed) (Shearer and Hays, 2010).

Water clarity is determined by measuring the horizontal distance that a black disc of standard size can be viewed under water (Figure 2-13). Where streams are big enough to employ this technique, black disc measurements are carried out monthly at HBRC SOE monitoring sites.

ANZECC (2000) and the Regional Resource Management Plan (HBRC, 2006b) defines a minimum water clarity of 1.6 m for contact recreation waters. However, to maintain the foraging efficiency of drift feeding trout Hay et al. (2006) recommend a minimum water clarity of 5 m for outstanding or regionally significant trout fisheries and 3.5m for trout fisheries of lesser importance.

Black disc and turbidity highlights in the Ngaruroro and Tūtaekurī catchments

• Ngaruroro at Kuripapango and Tūtaekurī at Lawrence Hut have the clearest water measured in the Hawke’s Bay region.

• Water clarity in the Ngaruroro declines significantly towards the sea, and is amongst the 10 sites with lowest clarity regionally.

• Water clarity declined most strongly between the most upstream (near natural) reference site and the next site further downstream in both the Ngaruroro and the Tūtaekurī.

• Sediment is likely to come into the river from tributaries as well as the riparian margins of the main stems.


Figure 2-13: Black disc viewing distance assessment to measure water clarity.

The Ngaruroro at Kuripapango and Tūtaekurī at Lawrence Hut are the two sites with the clearest water of all Hawke’s Bay SOE sites (Appendix D). Median black disc viewing distances greater than 5 m, and at times more than 10 m, were recorded (Figure 2-14). Water clarity at the upper sites in the Ngaruroro and Tūtaekurī was generally above the guideline for outstanding trout fisheries (Figure 2-14).

By the time the water in the Ngaruroro reaches the lower mainstem, clarity has decreased so much, that at Fernhill and Chesterhope black disc results rank amongst the bottom 10 sites regionally. Contrasting this, the site closest to the sea in the Tūtaekurī mainstem (at Brookfields Bridge) ranks 35 out of 81.

In both the Ngaruroro and Tūtaekurī rivers, the most pronounced reduction in water clarity was in the upper reaches just after the water comes out of the area predominantly in native vegetation. In the Ngaruroro between Kuripapango and Whanawhana, the viewing distance decreased in median clarity from 5.7 m to less than 2 m. in the Tūtaekurī River between Lawrence Hut and upstream of the confluence with the Mangaone River, water clarity decreased from 7 m to 2.5 m.

At the sites closest to the sea, the Ngaruroro at Chesterhope had a median clarity of 1 m, which was below the guideline for contact recreation, and Tūtaekurī at Brookfields Bridge had a median clarity of 2 m, above the guideline for contact recreation (Figure 2-14). Some tributaries had greater water clarity than the mainstem. The Poporangi and Tūtaekurī-Waimate streams had the lowest water clarity, being at or below the 1.6 m clarity guideline for contact recreation.

Excellent water clarity was measured only at the reference sites with predominantly intact native vegetation in their catchment. The pronounced loss in clarity, below the upper area in native bush, is most likely caused by several factors. The steep topography will result in sediment being held in suspension due to turbulent water. Coming into the lower, flatter reaches of the mainstem, sediment settles out at a faster rate, and additional sediment coming into the water may not result in as much water clarity reduction as in the upper reaches. The sources of sediment can be multiple as well. In the upper Ngaruroro, where steep cliffs line the mainstem in many parts, some sediment may be contributed by slips, but also stock have access to the mainstem in other parts, which also increases sediment input. So, in addition to what is carried in from tributaries where streams are not protected from runoff or stream banks are eroding, the mainstem receives sediment directly. This may explain why some of the tributaries have better water clarity than the mainstem.


Natural weathering of rock produces a coarser particle size sediment than topsoil that is lost in areas under agriculture or pastoral farming. These finer soil particles are held in suspension for longer and therefore have a higher impact on clarity and turbidity.

The data reported here include all flows. Water clarity under low flow conditions, when contact recreation is most likely, is shown in Appendix A. At less than median flow, sites in the Ngaruroro mainstem had a median black disc viewing distance at or greater than 2 m, and were better than ANZECC guideline for contact recreation.

Figure 2-14: Water clarity (black disc measurements) at Ngaruroro and Tūtaekurī SOE sites. The blue line is the Hay and Hayes (2006) ‘Outstanding trout fishery’ limit; the green line the ‘Significant trout fishery’ limit. The amber line is (ANZECC, 2000)/ HBRC RRMP 2006 recreational amenity limit. The sites Ngaruroro at Kuripapango and Tūtaekurī at Lawrence Hut are upland sites. All other sites are lowland according to ANZECC guidelines. SOE sites for the Mohaka River U/S Taharua confluence and the Ngaruroro River at Whanawhana (shaded) are included as Upland (U) and Lowland (L) reference sites for comparison.

There is a direct relationship between water clarity, as measured using a black disc, and turbidity: The higher the turbidity, the lower the water clarity. At very low turbidity levels a small increase in turbidity results in a large decrease in black disc. Turbidity readings less than 1 Nepholometric Turbidity Unit (NTU) typically


produce black disc distances greater than 3.5 m, which are distances optimal for drift feeding trout (Hay et al. (2006). Such turbidity readings reflect very low numbers of suspended particles in the water column. Very minor increases - whether caused by the presence of soft-sedimentary geology like mudstone or papa rock, or by minor catchment disturbance causing increased sediment transport, will cause minor increases in turbidity and rapid reductions in water clarity. Heavy rain and associated floods mobilise catchment sediment and cause substantial turbidity increases of 500 NTU or more.

Turbidity increased from upstream to downstream in a similar way as the water clarity decreased (Figure 2-15). The tributaries had lower turbidity than the mainstem (Figure 2-16). Turbidity stayed below ANZECC trigger values at most Ngaruroro sites, except for in the mainstem downstream Hawke’s Bay Dairies and at Fernhill. Turbidity in the Tūtaekurī River increased between Lawrence Hut and upstream of the Mangaone confluence, but generally stayed below ANZECC turbidity trigger values at all sites.

Figure 2-15: Turbidity (NTU) at Ngaruroro and Tūtaekurī River SOE sites. The blue line is (ANZECC, 2000) ‘Upland’ TN trigger value; the red line to (ANZECC, 2000) ‘Lowland’ TN trigger value. The sites Ngaruroro at Kuripapango and Tūtaekurī at Lawrence Hut are upland sites. All other sites are lowland according to ANZECC guidelines. SOE sites for the Mohaka River U/S Taharua confluence and the Ngaruroro River at Whanawhana (shaded) are included as Upland (U) and Lowland (L) reference sites for comparison.


Trend analysis on clarity and turbidity data (Table 2-5) shows that turbidity increased significantly over the last 6 years in the Ngaruroro downstream Hawke’s Bay Dairies, and clarity decreased in the Ngaruroro at Fernhill. Water clarity in the Waitio increased over the 6 years. All three sites had corresponding trends in the other (clarity or turbidity) metric, but these were not statistically significant.

Table 2-5: Trend analysis results for black disc clarity and turbidity at Ngaruroro and Tūtaekurī SOE sites period 2012 to 2018. Includes only sites with sufficient data and monitoring length for trend analysis. In bold: significant trend when p < 0.05. Cells shaded blue for improving trend, red for deteriorating trend.

Site

Black Disc Turbidity



Ngaruroro Rv at Kuripapango (NIWA) 5.900 0.817 0.475 1.010 0.679 -1.792 Ngaruroro Rv at Whanawhana 1.945 0.320 -5.078 3.130 0.240 5.763 Ohara Strm 3.400 0.540 -32.581 1.390 0.270 61.709 Poporangi Strm 1.625 0.949 -0.329 2.680 0.194 8.168 Maraekakaho Strm 3.200 0.940 -0.913 0.905 1.000 0.000 Ngaruroro Rv D/S HB Dairies 1.050 0.100 -9.628 6.985 0.020 8.995 Waitio Strm 4.000 0.020 9.985 1.230 0.280 -6.021 Ohiwa Strm 3.150 0.580 3.393 1.200 0.580 -6.329 Ngaruroro Rv at Fernhill 0.845 0.050 -6.408 6.505 0.190 5.443 Tūtaekurī-Waimate Strm 1.550 0.620 5.465 3.420 1.000 -2.044 Ngaruroro Rv at Chesterhope (NIWA) 0.950 0.263 6.810 4.480 0.585 -3.872 Tūtaekurī Rv at Lawrence Hut 7.250 0.160 -4.233 0.780 0.680 2.098 Mangatutu Strm 1.525 0.510 -3.459 3.210 0.520 3.112 Tūtaekurī Rv U/S Mangaone 2.300 0.530 -4.215 2.5/8 0.530 3.270 Mangaone Rv at Rissington 2.100 0.950 0.791 2.490 0.150 6.737 Tūtaekurī Rv at Brookfields Br 2.000 0.670 3.353 2.470 1.000 2.225


Figure 2-16: 5 year median turbidity levels at Ngaruroro and Tūtaekurī SOE sites including trend direction. Arrows indicate direction of significant trends, with blue arrows for improvement and red arrows for deterioration. 6 years of record between 2012 and 2018 for trend analysis.


2.4 Bacteriological water quality – E. coli

Escherichia coli (E. coli) levels have been routinely monitored throughout the Ngaruroro and Tūtaekurī catchments as an indicator of microbiological water quality. E. coli is a bacterium commonly found in the lower intestine of warm-blooded animals and indicates the presence of pathogens of faecal origin in the water. E. coli is used to assess the level of health risk to water users having direct contact with water.

The 2003 microbiological water quality guidelines (MfE/MoH, 2003) define a 3-mode management system for recreational freshwaters: Acceptable/Green (E. coli < 260 counts/100 mL); Alert/Amber (E. coli < counts 550/100 mL) and Action/Red (E. coli > counts 550/100 mL). The red mode indicates an unacceptable level of health risk to contact recreation users (e.g. swimmers). These are single-value criteria, designed to trigger further investigation and additional sampling (amber mode) and positive action to identify the source(s) of contamination and warn recreational users (red mode). The < 550 counts/100 mL amber level has been used in this report to assess suitability for swimming at all river flows.

There were typically very low levels of bacteria at all monitoring sites across both the Ngaruroro and Tūtaekurī catchments (Figure 2-18). E. coli levels stayed generally within the MfE acceptable/green mode for recreational freshwaters at all flows. Only the Mangatutu Stream and the Mangaone River showed some high E. coli samples that were in the red/action mode at times (Figure 2-17).

Bacteriological water quality highlights in the Ngaruroro and Tūtaekurī catchments

• All sites in the Ngaruroro and Tūtaekurī catchments had low levels of E. coli within the acceptable / green mode for recreation (MfE/MoH 2003).

• All main stem sites in the Ngaruroro and Tūtaekurī rivers were suitable for primary contact recreation under the NOF framework, (Ngaruroro: A band; Tūtaekurī A and B bands).

• Some tributaries fell into band D (not suitable for primary contact recreation) for overall grade, but when primary contact recreation is limited to normal flows (<median), all sites are suitable for contact recreation.


Figure 2-17: Bacteriological water quality levels (E. coli ) at Ngaruroro and Tūtaekurī SOE sites. The blue line is the MfE and MoH (2003) amber alert level; the red line the MfE and MoH (2003) red alert level. The sites Ngaruroro at Kuripapango and Tūtaekurī at Lawrence Hut are upland sites. All other sites are lowland according to ANZECC guidelines. SOE sites for the Mohaka River U/S Taharua confluence and the Ngaruroro River at Whanawhana (shaded) are included as Upland (U) and Lowland (L) reference sites for comparison.

The NPS-FM (MfE, 2017) requires councils to set a freshwater objective for E.coli in all rivers. In the Guide to Attributes report (MfE, 2018) the E.coli attributes of the NPS-FM are explained in the following way:

The Escherichia coli (E. coli) attribute states define E. coli concentrations where different percentages of the population are at risk of Campylobacter infection through ingestion of water during recreation activities. The E. coli attribute describes different statistical measures of the distribution of E. coli concentrations, and the associated risk of Campylobacter infection through ingestion of water during recreation activities (McBride, 2012); (MfE and MoH, 2003).

Each of the statistical measures are:

• percentage of exceedances greater than 540 cfu/100ml: This measure indicates how often the level of E. coli exceeds the acceptable threshold for swimming


• percentage of exceedances greater than 260 cfu/100ml: This measure indicates how often the E. coli exceeds the point where additional monitoring is required

• median: The mid-point of E. coli levels

• 95th percentile: an indication of the top of the range of E. coli levels within the distribution.

The thresholds of what has been considered an acceptable level of E. coli (discussed in the NPS-FM document) are based on a ‘quantitative microbial health risk assessment’ (QMRA) that assessed what the corresponding risk of Campylobacter infection would be for different concentrations of E. coli.

Infection risk profiles have been developed to relate E. coli levels and the proportion of population at risk of Campylobacter infection for activities likely to involve full immersion such as swimming or white water rafting (McBride, 2012); (MfE and MoH, 2003).

The E. coli attribute table has five categories, also called attribute states (i.e. A, B, C, D and E) (see Table 1-7 and Appendix E). Each attribute state has four criteria, or ‘statistical tests’, that need to be satisfied for water quality to be in that attribute state. Higher attribute states provide lower levels of infection risk for each activity type. All four criteria are necessary to establish an attribute state. If one or more criteria can’t be satisfied, a lower attribute state must apply. For example, for water quality to be in the A state, it must:

• not exceed 540 cfu/100ml more than 5% of the time

• not exceed 260 cfu/100ml more than 20% of the time

• have a median of ≤130 cfu/100ml

• have a 95th percentile of ≤540 cfu/100ml.

If any of those criteria are not satisfied, water quality is in a lower state (eg, B, or lower, as long as all criteria can be satisfied). Note there is an overlap in the ‘exceedances over 260 cfu/100ml’ test between states B (20-30% exceedance) and C (20-34%). This overlap occurs because of an overlap in the underlying distribution used to set the attribute states. For example, if a site satisfied all of the other tests for B and had a 260 exceedance of 29% it would still be band B. If one of the other tests did not meet the band B criteria it would drop down to band C.

When categorising individual rivers or lakes using the E. coli attribute, the 95th percentile criteria may not apply if the council considers there is insufficient monitoring data to establish a precise 95th percentile. This is to acknowledge that monitoring data at this scale may be limited, and may not be sufficient to model the 95th percentile precisely.

Band A (dark blue), band B (light blue) and band C (yellow) are categories suitable for primary contact recreation (MfE, 2017).

Table 2-6 shows the NOF bands for Ngaruroro and Tuatekuri SOE sites. All mainstem sites in the Ngaruroro and Tūtaekurī rivers are suitable for primary contact recreation (overall grade A and B). Sites not suitable for swimming are in the Maraekakaho, Ohiwa and Tūtaekurī-Waimate streams in the Ngaruroro catchment, and the Mangatutu Stream and the Mangaone River in the Tūtaekurī catchment. These streams are graded in the D band, which means for at least 20-30% of the time, the estimated infection risk is ≥50 in 1000 people involved in full immersion activities such as swimming or white water rafting. The predicted average infection risk is >3%. The actual risk of an infection will generally be less if a person does not swim during high flows. This applies to the tributaries that are in the D band overall, but are in the B or C band when the 95th percentile


is not used for grading purposes (Table 2-6). The 95th percentile of E. coli in <median flows, when people tend to swim, is below 540 cfu/100ml at all sites (Appendix A).

5-year median E.coli levels at SOE sites are shown in a map in Figure 2-18.

Table 2-6: NPS-FM NOF bands (MfE, 2018) for E.coli in the Tūtaekurī and Ngaruroro catchments. Monitoring period 2013 to 2018. Overall grade must satisfy all 4 criteria of numeric attribute states in the same band (Appendix E). No 95th percentile: Top range of E.coli levels excluded. Overall grade A, B and C bands are categories suitable for primary contact recreation. * Short-term monitoring site (3 years), excluded from E.coli attribute analysis.

Site

E. coli

Overall grade No 95th percentile

Ngaruroro at Kuripapango (NIWA) A A Ngaruroro Rv at Whanawhana A A Ohara Strm* NA NA Poporangi Strm A A Maraekakaho Strm D B Ngaruroro D/S HB Dairies A A Waitio Strm B B Ohiwa Strm D B Ngaruroro Rv at Fernhill B B Tūtaekurī-Waimate Strm D B Ngaruroro at Chesterhope (NIWA) A A Tūtaekurī Rv at Lawrence Hut A A Mangatutu Strm D C Tūtaekurī Rv U/S Mangaone Rv B B Mangaone Rv at Rissington D C Tūtaekurī Rv at Brookfields Br B B

Compared to other SOE sites, the Ngaruroro mainstem has particularly low E. coli concentrations. The upper Ngaruroro at Kuripapango and Whanawhana rank first and second best, respectively, in Hawke’s Bay. The mid reach site downstream Hawke’s Bay Dairies ranks amongst the top 10, and even the most downstream site at Chesterhope is in the top third of SOE sites in the region. The tributaries have higher E. coli concentrations, which shows that the large volume of pristine water from the upper catchment in native vegetation dilutes the E. coli concentrations from the tributaries.


Table 2-7: Trend analysis results for E. coli at Ngaruroro and Tūtaekurī SOE sites period 2012 to 2018. Includes only sites with sufficient data and monitoring length for trend analysis. In bold: significant trend when p < 0.05. Cells shaded blue for improving trend, red for deteriorating trend.

Site

E. coli


Ngaruroro Rv at Kuripapango (NIWA) 3.1 0.305 2.04 Ngaruroro Rv at Whanawhana 4 0.060 17.6 Ohara Strm* NA NA NA Poporangi Strm 46 0.174 7.34 Maraekakaho Strm 68 0.320 8.03 Ngaruroro Rv D/S HB Dairies 11 0.090 16.8 Waitio Strm 30 0.860 0.00 Ohiwa Strm 100 0.400 12.85 Ngaruroro Rv at Fernhill 37 0.010 16.0 Tūtaekurī-Waimate Strm 75 0.600 -5.01 Ngaruroro Rv at Chesterhope (NIWA) 20.1 0.961 0.00 Tūtaekurī Rv at Lawrence Hut 14 0.080 5.34 Mangatutu Strm 43.5 0.380 6.29 Tūtaekurī Rv U/S Mangaone 16 0.030 18.5 Mangaone Rv at Rissington 50 0.310 6.68 Tūtaekurī Rv at Brookfields Br 21 0.220 10.2 Raupare Dr 320 0.150 14.5

Trend analyses showed significantly increasing trends for E. coli concentrations over the time period of 6 years in the mainstems of the Ngaruroro at Fernhill and in the Tūtaekurī upstream of the Mangaone confluence (Table 2-6). There is no increasing trend in any tributaries upstream of these sites, nor in the mainstem downstream (Ngaruroro at Chesterhope and Tūtaekurī at Brookfields Bridge). The causes for these localised trends need further analysis. Short-term trends often reflect part of natural variability, rather than a long-term trend caused by changes in the catchment. As already discussed in relation to trends in nutrient concentrations, climate could be a driver for the observed trends, and an in-depth analysis with trend results including longer-term datasets and climate and land use data will be done in a separate trends report. Trend analysis started in a significant drought year (2012), and in the following years rainfall was lower than average. For the last two years of the trend analysis, rainfall was higher than average with severe storms and localised flooding. The rainfall total had a return period in excess of 100 years in the Mangaone River area.


Figure 2-18: 5 year median E.coli levels at Ngaruroro and Tūtaekurī SOE sites including trend direction. Arrows indicate direction of significant trends, with blue arrows for improvement and red arrows for deterioration. 6 years of record between 2012 and 2018 for trend analysis.


2.5 Dissolved oxygen

Dissolved oxygen (DO) is an important component in the life supporting capacity of freshwater ecosystems. Humans absorb oxygen from air through their lungs, while aquatic organisms absorb oxygen from water through their gills. Fish, invertebrates and other organisms are stressed when insufficient oxygen is dissolved in water.

Various elements of aquatic systems either consume and/or produce oxygen. Plants and algae growing in the water produce oxygen as a by-product of photosynthesis. This supplements oxygen passively diffusing into the water from the atmosphere or being infused by turbulence or aeration in steeper or fast flowing streams, a process known as re-aeration (Figure 2-19). However, plants and algae also use oxygen when they respire, as do animals, fungus and bacteria living in the water. The breakdown of organic matter by aerobic micro-organisms also consumes oxygen and is termed the ‘biochemical oxygen demand’ (BOD). This process also occurs in the sediments and is termed the ‘sediment oxygen demand’ (SOD) as shown in Figure 2-19.

In unshaded, slow-flowing streams with high nutrient inputs, excessive growth of plants and algae results in extremely high dissolved oxygen levels during the day, then extremely low dissolved oxygen levels during the night or early morning, when these plants and algae consume more oxygen than the waterway is capable of supplying. The low dissolved oxygen conditions mean there is little oxygen for fish and other organisms to use (Figure 2-19).

Three main processes are likely to cause low dissolved oxygen conditions:

1) Aquatic plant and algal respiration during the night

2) Oxygen consumption by microbes that break down organic matter

3) Low reaeration of oxygen from the atmosphere, which may occur in low gradient streams with reduced flow and/or without flow turbulence typically provided by logs, roots, plants or variable stream banks in lowland streams

Localised DO may also be low in reaches where substantial upwelling of potentially low-oxygen or anoxic groundwater occurs. Likewise, in wetland systems where bacterial respiration levels are high, oxygen levels can be very low. These are consequences of natural background conditions and are independent of anthropogenic (human) influences.

Dissolved oxygen highlights in the Ngaruroro and Tūtaekurī catchments

• Based on spot measurements, DO concentrations were typically good throughout the Ngaruroro and Tūtaekurī river catchments.

• Some Ngaruroro tributaries had higher DO variability than other sites including occasional low DO saturation. Here, nuisance aquatic plant growth causes DO highs and lows due to the contrasting balance between photosynthesis and respiration as light availability changes over the course of a day and night.


Figure 2-19: Schematic of the major processes influencing dissolved oxygen concentration in rivers. DO = dissolved oxygen; BOD = biochemical oxygen demand; SOD = sediment oxygen demand (Davies-Colley et al., 2013).

A waterway with DO consistently below 5.0 mg/L is unable to support sensitive species and the ecological integrity of these systems will be compromised. DO greater than 8.0 mg/L is typically capable of supporting the full range of aquatic organisms (MfE, 2013).

Colder water can hold more oxygen than warmer water. When water temperature is greater than 27oC it cannot hold more than 8.0 mg/L of oxygen. Unshaded systems that overheat during the day can also be depleted of oxygen.

Increased water temperature detrimentally affects trout in two ways. As water temperature increases, trout oxygen requirements also increase as they become more active (Elliott, 1994). At the same time, increasing water temperatures decrease the oxygen-carrying capacity of water.

Salmonids are particularly sensitive to low DO concentrations (Dean and Richardson, 1999). Free swimming trout can tolerate DO concentrations of 5 to 5.5 mg/L, but the saturation should be at least 80% (Hay et al., 2006). RMA Schedule 3 states that “The concentration of dissolved oxygen shall exceed 80% saturation concentration” in Class AE (Aquatic Ecosystems), F (Fishery) and FS (Fish Spawning) waters”.

ANZECC (1992) guidelines recommend minimum DO concentrations of 6 mg/L and 80% saturation. Hay et al. (2006) suggest these limits should be seen as short-term exposure levels (i.e. occurring only for a few days), as data suggest that long-term exposure to DO levels of 6 mg/L can impair the growth of salmonids, including trout (CCME, 1997). The RMA proposes a default standard of 80% DO saturation, which has been adopted widely across the country.

The NPS-FM (MfE, 2017) requires councils to set freshwater objectives for DO attributes in rivers downstream of point source discharges, not at SOE sites. The DO attribute states are defined in the Freshwater NPS by


two expressions of DO minima; the lowest 7-day mean of daily minima (the ‘7-day mean minimum’) and the lowest daily minimum (the ‘1-day minimum’), which requires continuous measurement of DO. Currently, continuous DO measurements are carried out at sites with targeted investigations, not routinely at SOE monitoring sites.

Based on the SOE spot measurements, DO concentrations were typically good throughout the Ngaruroro and Tūtaekurī river catchments, with all sites recording oxygen saturation levels greater than 80% (Figure 2-20) and 8 mg/L (Figure 2-21) on nearly all occasions. Results of 5-year median DO saturation and concentration is shown on maps in Figure 2-22 and Figure 2-23 respectively.

Figure 2-20: Dissolved oxygen saturation at Ngaruroro and Tūtaekurī SOE sites. The red line is the RMA (1991) Schedule 3 lower limit of 80% for supporting salmoniid (trout) fisheries. The sites Ngaruroro at Kuripapango, Taurarau River, and Tūtaekurī at Lawrence Hut are upland sites. All other sites are lowland according to ANZECC guidelines. SOE sites for the Mohaka River U/S Taharua confluence and the Ngaruroro River at Whanawhana (shaded) are included as Upland (U) and Lowland (L) reference sites for comparison.

The results are not surprising for the mainstem sites, given the high-energy, turbulent nature of flow, with mostly gravel substrate producing well aerated water. This is coupled with low levels of in-stream productivity and relatively low levels of oxygen uptake through metabolic processes. This means large


fluctuations in DO concentrations would not be expected.

The Maraekakaho, Waitio, Ohiwa and Tūtaekurī-Waimate streams had a higher DO variability than other sites, including occasional low DO saturation (Figure 2-20). All four sites are macrophyte (aquatic plant) dominated (except for the Maraekakaho Stream that tends to switch between macrophyte and algal growth). Macrophyte growth can reduce in-stream DO levels through overnight respiration. These sites may also be influenced by upwelling of groundwater with low DO concentrations, which may cause locally low in-stream DO concentrations. The high variability in data, however, indicates that nuisance aquatic plant growth is more likely to be the problem, with high photosynthesis rates during daytime causing the oxygen highs and respiration at night the oxygen lows.

Figure 2-21: Dissolved oxygen concentration at Ngaruroro and Tūtaekurī SOE sites. The red line is the ANZECC (1992) guideline minimum DO concentration of 6 mg/L. The sites Ngaruroro at Kuripapango and Tūtaekurī at Lawrence Hut are upland sites. All other sites are lowland according to ANZECC guidelines. SOE sites for the Mohaka River U/S Taharua confluence and the Ngaruroro River at Whanawhana (shaded) are included as Upland (U) and Lowland (L) reference sites for comparison.


Figure 2-22: 5 year median DO saturation at Ngaruroro and Tūtaekurī SOE sites including trend direction. Arrows indicate direction of significant trends, with blue arrows for improvement and red arrows for deterioration. 6 years of record between 2012 and 2018 for trend analysis.


Figure 2-23: 5 year median DO concentration at Ngaruroro and Tūtaekurī SOE sites including trend direction. Arrows indicate direction of significant trends, with blue arrows for improvement and red arrows for deterioration. 6 years of record between 2012 and 2018 for trend analysis.


2.6 Biological indicators

2.6.1 Periphyton cover

Algae are found in many locations in rivers. They may drift in the water column in both rivers and lakes, but they are called periphyton when they are attached to objects underwater such as the streambed gravel, rocks, logs, branches or any other stable material.

Low levels of algal growth occur naturally in healthy riverine ecosystems. Algae are the main primary producers in streams and rivers, and are fundamental to the functioning of aquatic ecosystems (Biggs, 2000). They support invertebrate and fish productivity and diversity. But when periphyton cover grows too thickly, it can detrimentally affect ecosystem health and recreational values. Algal growth is controlled by several biotic and abiotic factors. Biotic factors include grazing by invertebrates, while abiotic factors are nutrient availability, available light, and the time available for algae to grow between flood flows that scour algae off the river bed (known as the ‘accrual’ period).

Regional climate determines the frequency of floods capable of resetting algae to low levels, thereby starting a new accrual period. Catchments in drier climates generally accumulate more algae between infrequent floods than those in regions with wetter climate and higher flood frequencies (Snelder et al., 2014).

Excessive periphyton growth can have detrimental effects on benthic habitat quality and macroinvertebrates, which can in turn affect native fish and trout growth, since macroinvertebrates are a food source for native fish and trout. Excessive growth can also cause wide daily variation in pH and dissolved oxygen concentrations, which can also detrimentally affect aquatic life (Biggs, 2000). By contrast, the benthic cyanobacteria Phormidium can be hazardous because it produces toxins.

Excessively long filamentous algae and thick mats are unsightly and can directly affect amenity/aesthetic values of a river, and the quality of fishing for anglers by fouling fishing lures and lines (Biggs, 2000, Wilcock et al., 2007).

The amount of algae present in a river can be assessed in terms of biomass, measured as the amount of Chlorophyll a per area (mg Chla/m2), or visually as proportional cover on the stream bed (% cover) in a defined reach. Algal biomass is an indicator related to the trophic state aspect of the ecosystem health value

Periphyton cover highlights in the Ngaruroro and Tūtaekurī catchments

• Periphyton cover in the Ngaruroro and Tūtaekurī main stems was indicative of an excellent to good ecological condition.

• The contact recreation guideline was only exceeded occasionally at one main stem site, in the Ngaruroro at Fernhill.

• Most tributaries in both the Ngaruroro and Tūtaekurī catchments had low algal cover.

• Nutrient concentration in the tributaries would support high algal growth rates, but stream bed substrate size (small gravel) and shade are probably factors that keep algal cover low at the monitoring sites.

• The Maraekakaho Stream was the only site with high algal cover, indicating a poor ecological condition, and exceeded the contact recreation guideline.


in rivers in the NPS-FM (MfE, 2017), and is used to assess the effects of in-stream nutrient concentrations, or enrichment (‘trophic state’). The frequency and intensity of algal blooms reflect respective nutrient enrichment.

The visual assessment of periphyton cover records mats and filamentous algae that have different thresholds in the New Zealand Periphyton Guideline (Biggs, 2000). Matheson et al. (2016) provide guidelines for a composite cover index integrating the different guidelines for mats and filamentous algae, the Periphyton Weighted Composite Cover (PeriWCC). As with algal biomass, higher periphyton cover (or %PeriWCC), reflects nutrient enrichment. PeriWCC guidelines relate to aesthetic, recreational, angling and ecological condition values. The PeriWCC assessment captures different types of algal growth forms, including cyanobacteria.

Figure 2-24: Periphyton cover (%PeriWCC) at Ngaruroro and Tūtaekurī SOE sites. The lines are boundaries between ecological condition classes as defined by Matheson et al. (2016): The blue line is the boundary between excellent and good ecological condition, orange line: boundary between good and fair, red line: boundary between fair and poor. The sites Ngaruroro at Kuripapango and Tūtaekurī at Lawrence Hut are upland sites. All other sites are lowland according to ANZECC guidelines. SOE sites for the Mohaka River U/S Taharua confluence and the Ngaruroro River at Whanawhana (shaded) are included as Upland (U) and Lowland (L) reference sites for comparison.


Periphyton cover results for the Ngaruroro mainstem sites were indicative of an excellent to good ecological condition (Figure 2-24). Ngaruroro at Whanawhana had significantly higher algal cover (17.3% PeriWCC) than the Tūtaekurī at Lawrence Hut (7% PeriWCC), although nutrient concentrations were very low at both sites (see Chapter 2.1.2). Under strongly N- and P-limited conditions, nutrients can be taken up rapidly by periphyton. Under those conditions, rapid nutrient uptake by plants reduces nutrient concentrations in the water column, while also facilitating higher periphyton growth rates. This effect may occur in the Ngaruroro because 10% of the catchment is in dry stock farming upstream of Whanawhana in the Taruarau tributary. This land-use may contribute nutrients that are not provided from the naturally-vegetated catchment at Lawrence Hut and Ngaruroro at Kuripapango. This pattern of periphyton growth may be exacerbated by long periods of low flow that do not ‘reset’ growth, coupled with sunny, warm weather.

A PeriWCC of 30% is the guideline for aesthetics and recreation (Matheson et al., 2016) which is exceeded occasionally in the Ngaruroro mainstem Fernhill (32% PeriWCC). In the mid Tuatekuri mainstem, upstream of the Mangaone confluence, periphyton cover is coming close to the guideline with 29% PeriWCC.

In the tributaries, PeriWCC was low except for the Maraekakaho Stream, where high periphyton cover indicates a poor ecological state. The Poporangi, Maraekakaho and Waitio Streams all have high dissolved nutrient concentrations available for periphyton growth, but the Poporangi Stream is partially shaded at the site and the Waitio Stream is macrophyte dominated. This may explain why algal cover is lower than expected in the context of the trophic state of the streams. The Maraekakaho is highly productive and switches between high aquatic plant (macrophyte) biomass and high algal cover.

No data are available for Ohiwa and Tūtaekurī-Waimate tributaries in the lower Ngaruroro catchment, which are macrophyte-dominated streams that are not suitable for periphyton monitoring.

Periphyton growth in the Tūtaekurī catchment was very low in the upper catchment (Tūtaekurī at Lawrence Hut). Algal cover was higher in the middle catchment (upstream of the Mangaone confluence), and again lower than 20% PeriWCC at Brookfields Bridge (Figure 2-24). Nutrient availability increases from upstream to downstream, and the lower algal cover may be reflective of finer gravel size limiting algal growth, as small gravel is less suitable for algal growth. Sites in the Mangatutu Stream and Mangaone River showed low levels of algal cover, which was again probably due to site conditions such as gravel size and shade that limits potential algal growth despite nutrient enrichment.


2.6.2 Macroinvertebrate Community Index

Macroinvertebrate communities are commonly used as an indicator of water quality and ecosystem health. The macroinvertebrate community of a stream adjusts to conditions in the aquatic environment, including naturally induced changes and stressors affecting ecosystem health. The macroinvertebrates collected at a site are exposed to changes in conditions at that site for periods of months, to a year or even several years, depending on their life cycle. Macroinvertebrate community composition changes as sensitive species experiencing stress are lost, which leads to a community dominated by more tolerant species. Both human activities and natural changes such as drought and floods, or natural variations in stream bed substrate type and water temperature may affect macroinvertebrate communities. Assessing the composition of macroinvertebrate communities provides a long-term and integrated view of water quality.

The Macroinvertebrate Community Index (MCI) was developed by Stark (1985) as a biomonitoring tool to assess stream health based on the presence or absence of certain invertebrate species. A higher MCI score indicates more pollution ‘intolerant’ or sensitive species are present. The MCI of a site can be used to assess the likely level of ecosystem degradation. Ephemeroptera (mayfly), Plecoptera (stonefly) and Trichoptera (caddisfly) larvae (called EPT taxa) are sensitive to pollution, so MCI scores are high when they are present. Community composition metrics like the proportion of EPT taxa present at a site can also be used as an indicator of stream health complementary to the MCI.

The MCI also has the potential to provide an indication of the relative availability of trout food species since many taxa that score highly in the MCI are also important prey for drift feeding trout (Hay et al., 2006).

The MCI summarises the complexity of stream health in a single numeric value that can be related to a wide range of factors. It is the most commonly used indicator of macroinvertebrate community health in large-scale monitoring and reporting in New Zealand, such as State of the Environment monitoring and reporting undertaken by Regional Councils and TLAs2. The quality classes indicated by the MCI score are shown in Table 2-8.

2 Territorial Local Authorities

Macroinvertebrate Community Index highlights in the Ngaruroro and Tūtaekurī catchments

• The MCI showed a gradient from excellent to fair condition from upstream (MCI 130) to downstream (MCI <100) in both, the Ngaruroro and Tūtaekurī catchments.

• There is a marked difference between hill country tributaries with the MCI indicating good to excellent condition, and lowland tributaries with the MCI indicating fair to poor condition.

• The differences in MCI scores reflect changes in water quality and habitat parameters, such as increases in sediment, substrate type, temperature, or periphyton biomass.


Table 2-8: MCI quality classes as defined by Stark and Maxted (2007).

≥120 Excellent quality, clean water

100-119 Good quality, possible mild pollution

80 – 99 Fair quality, probable moderate pollution

< 80 Poor quality, probable severe pollution

In both the Ngaruroro and Tūtaekurī catchments, the MCI indicates a deteriorating gradient from upstream to downstream, as with the previous water quality parameters (Figure 2-25 and Figure 2-26).

In the Ngaruroro mainstem MCI indicated excellent water quality in the upper catchment (MCI 130 at Kuripapango), good water quality in the mid catchment (MCI 110 at downstream Hawke’s Bay Dairies) and at the threshold between good and fair in the lower catchment (MCI 100 at Fernhill and Chesterhope). MCI in the tributaries in the upper catchment were between good and excellent. The tributaries Maraekakaho, Waitio, Ohiwa and Tūtaekurī-Waimate streams all had MCI scores at or below 100, the Tūtaekurī-Waimate scored lowest with an MCI of 77 (poor class).

The Tūtaekurī mainstem had a similar pattern as the Ngaruroro: MCI was excellent at the most upstream site at Lawrence Hut with a median MCI of 130, the MCI decreased to 104 upstream of the Mangaone confluence, and the furthest downstream site at Brookfields Bridge scored an MCI of 93, in the fair quality class. The tributaries Mangatutu and Mangaone had good to excellent MCI results.

EPT taxa are mostly pollution sensitive taxa that indicate good water quality when present in higher proportions in a macroinvertebrate community. The proportion of EPT taxa in the macroinvertebrate community at SOE sites are in Appendix A in the column ‘%EPT taxa’. Close to 60% of the macroinvertebrate community consisted of the sensitive EPT taxa at the upper reference sites Ngaruroro at Kuripapango. In the middle reach of the Ngaruroro mainstem more than half of the macroinvertebrate community were EPT taxa, and in the Ngaruroro at Chesterhope EPT taxa dropped to 46%. The Ngaruroro tributaries ranged from 75% EPT taxa (Ohara Stream) to 1% in the Tūtaekurī-Waimate Stream with the lowest proportion of EPT taxa. The decrease of EPT taxa from upstream to downstream was more pronounced in the Tūtaekurī than in the Ngaruroro: In the Tūtaekurī at Lawrence Hut 75% of the macroinvertebrate community were EPT taxa. The middle reach of the Tūtaekurī River had 44% EPT taxa, and the lower Tūtaekurī mainstem (at Brookfields Bridge) had only 27% EPT taxa. The Mangaone River and the Mangatutu Stream had 71% and 37% EPT taxa respectively.

Ngaruroro at Kuripapango and Tuatekuri at Lawrence Hut had the 3rd and 4th highest MCI scores in Hawke’s Bay. MCI scores in the Ohiwia, Maraekakaho and Tūtaekurī -Waimate streams in the Ngaruroro catchment are among the lowest third of SOE sites regionally.

The change in community composition and in MCI scores from upper to lower catchment is accompanied by changes in water quality or habitat parameters, such as increases in suspended sediment concentrations (indicated by turbidity and water clarity), deposited sediment, substrate type, temperature, and excessive algae or aquatic plant growth. These factors are known to influence macroinvertebrate communities.


Figure 2-25: MCI levels at Ngaruroro and Tūtaekurī SOE sites. The lines are boundaries between MCI quality classes as defined by Stark and Maxted (2007): Blue line is the boundary between excellent and good classes, orange line: boundary between good and fair classes, red line: boundary between fair and poor classes. SOE sites for the Mohaka River U/S Taharua confluence and the Ngaruroro River at Whanawhana (shaded) are included as Upland (U) and Lowland (L) reference sites for comparison.


Figure 2-26: 5 year median MCI levels at Ngaruroro and Tūtaekurī SOE sites including trend direction. Arrows indicate direction of significant trends, with blue arrows for improvement and red arrows for deterioration. 6 years of record between 2012 and 2018 for trend analysis.


2.6.3 Physical Habitat

Physical habitat is the living space of aquatic flora and fauna, and it is a critical component of good stream health (Clapcott J, 2018). In general, a more diverse habitat will support a more diverse range of flora and fauna (Benton et al., 2003). Waterways around New Zealand, and the world, have been subjected to various modifications that have simplified habitat structure and reduced habitat quality (Maddock, 1999). This includes activities such as channel straightening and deepening, piping, removal of riparian vegetation and the reduction of riparian buffer widths, damage caused by livestock access and sedimentation resulting from bank and broader catchment erosion processes (Maddock (1999); Scarsbrook and Halliday (1999); Shields Jr et al. (2006)). In urban areas, the use of concrete and other artificial materials can result in stream channels that have little connection left with the natural world, with extreme examples involving large proportions of waterways flowing through underground pipes (Reid et al., 2008). The cumulative degradation of habitat often results in waterways being treated like ‘drains’ instead of being recognised as a living space for aquatic flora and fauna. This physical degradation has been widespread in rural and urban areas alike (Reid et al. (2008); Quinn (2009)). Example photos of a range of physical habitat conditions is shown in Figure 2-27.

Habitat highlights in the Ngaruroro and Tūtaekurī catchments

• Rapid Habitat Assessment ranged between the highest RHA score of 85 (Ohara Stream) and the lowest score of 35 (Tūtaekurī -Waimate Stream).

• The near natural sites scored lower than expected because the RHA focusses on biodiversity, not naturalness. Also, the wide channels were not shaded (even by mature trees), resulting in a lower score.

• The predominant factor scoring particularly low at most sites is the lack of riparian vegetation.

• Lowland streams (Waitio, Ohiwa, Tūtaekurī-Waimate) have the lowest RHA score out of SOE sites in the Ngaruroro and Tūtaekurī catchments.


Figure 2-27: Physical habitat: a critical component of stream health. Good riparian function (upper left) is impaired by unrestricted stock access and an over deepened channel (upper right). The most severely compromised waterways are often treated like 'drains' (bottom right).

Physical habitat quality can be considered at a broad range of scales, from the entire catchment right down to a minute and sub-reach scale (Frissell et al., 1986). For the purpose of SOE reporting, we have focused on a rapid habitat assessment method that has been standardised for use by all regional councils in New Zealand (Clapcott, 2015). The rapid habitat assessment method visually evaluates ten habitat parameters at a site scale (≈100m) and assigns each a score between 1 and 10. Individual scores are summed to produce an overall rapid habitat assessment score (RHA). The 10 parameters are;

1. Deposited sediment The area of stream bed covered by sediment.

2. Invertebrate habitat diversity The number of different habitat types (e.g. boulders, wood, leaves) suitable for different aquatic macroinvertebrates.

3. Invertebrate habitat abundance The area of habitat that is suitable for sensitive aquatic macroinvertebrates.

4. Fish cover diversity The number of different habitat types suitable for fish (e.g. woody debris, undercut banks, root mats).


5. Fish cover abundance The area of suitable habitat available for fish.

6. Hydraulic heterogeneity The range of different hydraulic features present, such as pools, riffles and backwaters.

7. Bank erosion The extent of stream bank erosion.

8. Bank vegetation The maturity, diversity and naturalness of riparian vegetation.

9. Riparian width The width of the riparian buffer zone.

10. Riparian Shade How much of the stream is shaded from the sun.

For soft bottomed streams that naturally have an extensive deposition of fine sediment, the ‘deposited sediment’ score is excluded and the maximum score is out of 90.

The RHA scores at the two sites Tūtaekurī at Lawrence Hut and Ngaruroro at Whanawhana are 81 and 68, respectively. This may seem unusually low for near pristine sites. The RHA focuses on biodiversity but some reaches at SOE sites may be (naturally) fairly uniform. Wide channels score poorly due to lack of shade, but even under natural conditions trees cannot grow tall enough to shade the entire channel. This is the case for both of these sites and are the reason for scoring lower than expected. There are ongoing national work streams to improve our ability of assessing habitat quality from different perspectives and at different scales (Clapcott, 2015, Holmes et al., 2018).

In the Ngaruroro catchment the three lowest habitat scores were observed in the lowland sites Tūtaekurī-Waimate, Ohiwa and Waitio streams. Tūtaekurī-Waimate and Ohiwa streams score poorly across all habitat parameters except bank erosion. By contrast the Waitio Stream has good habitat for fish and invertebrates, but scores very poorly on all parameters relating to the condition of its river banks. The best habitat score in the Ngaruroro catchment was observed in the Ohara Stream. The reference site Ngaruroro at Kuripapango (NIWA) does not get assessed for habitat.

The highest median habitat score of 81 was in the Tūtaekurī catchment, at the reference site Tūtaekurī at Lawrence Hut. The mid Tūtaekurī mainstem (upstream of the confluence with the Mangaone River), and the two tributary sites in the Mangatutu and Mangaone River were near the upper quartile score of sites around New Zealand (Clapcott, 2015). At the bottom of the catchment, the site Tūtaekurī at Brookfields Bridge scored less than the median habitat score nationally.


The lowest scores tended to relate to the riparian shade parameter. There are a few large river sites that are too wide to be shaded, even by mature trees, which applies also to reference sites like the Tūtaekurī at Lawrence Hut. However, shading is possible at the majority of the sites, and these sites currently lack vegetation like shrubs or trees.

Figure 2-28: Rapid Habitat Assessment score (RHA score) at Ngaruroro and Tūtaekurī SOE sites. The lines are thresholds for ecological condition, with the 25th percentile = 47, median = 63, and 75th percentile = 75, of the distribution of 560 New Zealand sites (Clapcott 2015). SOE sites for the Mohaka River U/S Taharua confluence and the Ngaruroro River at Whanawhana (shaded) are included as Upland (U) and Lowland (L) reference sites for comparison


2.7 Summary and conclusion for the Ngaruroro and Tūtaekurī River catchments Ngaruroro and Tūtaekurī catchments

• Toxicity effects on aquatic organisms from nitrate and ammonia were not an issue anywhere in the Ngaruroro and Tūtaekurī catchments, as concentrations were always low. Ammonia levels were mostly below detection limit.

• Escherichia coli (E. coli) levels were very low in both catchments and were below the lowest guideline (‘alert’-) level. All mainstem sites in the Ngaruroro and Tūtaekurī rivers were suitable for primary contact recreation under the NOF framework. Some tributaries fell into the D Band (not suitable for primary contact recreation), but when full immersion activity is limited to normal flows (<median flows), all sites are suitable.

Ngaruroro catchment

The Ngaruroro mainstem is in excellent condition in the upper to middle catchment. The lower reaches showed some minor enrichment in nutrients. Water quality parameters in general showed a minor upstream to downstream decline, which was reflected in the macroinvertebrate community. Periphyton cover was indicative of a good ecological condition, but recreational guidelines were exceeded on rare occasions at Whanawhana and Fernhill. Overall water quality and ecology of the Ngaruroro River mainstem was healthy.

Water clarity decreased, while turbidity increased, from upstream to downstream in the Ngaruroro catchment. The mid to lower mainstem water clarity was below contact recreation guidelines. Soft rocks in the catchment increases erosion risk, and sediment appears to enter the Ngaruroro from the tributaries as well as the riparian margin of the mainstem.

All Ngaruroro tributaries (other than the Ohara Stream) were enriched in nutrients, especially phosphorus, which was always above guideline levels. The influence of nutrient loads coming from the tributaries into the mainstem had only a minor effect on the water quality in the mainstem Ngaruroro, because large volumes of water with high water quality from the pristine upper catchment dilutes the influence of the tributaries. But nutrient loads coming from the tributaries are relevant for the health of the Waitangi Estuary as a receiving environment.

Tūtaekurī catchment

The Tūtaekurī mainstem showed some enrichment in nutrients from upstream to downstream, particularly in phosphorus, which was always above guideline levels at the lower mainstem sites. MCI also showed a gradient from upstream to downstream, and declined from excellent to fair towards the lower reaches.

Tūtaekurī tributaries had water quality issues similar to the Ngaruroro tributaries, with elevated nutrient concentrations. The high phosphorus concentrations were mostly above guidelines. MCI was good across all tributary sites. Periphyton biomass was high in the Mangatutu Stream, and low in the upper Mangaone River. The effect of tributary nutrient loads on mainstem water quality was greater in the Tūtaekurī than in the Ngaruroro, because the volume of water coming from the pristine upper catchment is lower and the dilution effect less than in the Ngaruroro. Nutrient loads are important to manage with regards to the health of the receiving Waitangi estuary.


3 Water Quality of the Karamū and Ahuriri Catchments: Long-term SOE data

3.1 Nutrients Background information on nutrients in an aquatic environment is provided in Chapter 2.1.

3.1.1 Total nitrogen (TN) and total phosphorus (TP)

Total nitrogen concentrations were high in the Karamū catchment (Figure 3-1). Samples were always above the ANZECC lowland trigger value of 0.614 mg/L in the Karewarewa, Awanui, Poukawa and Taipo Streams and TN generally exceeded the trigger value in the Clive mainstem. In the Herehere and Raupare Streams, TN median concentrations were lower than at the other sites, mostly below the ANZECC lowland trigger value.

A map of 5-year median TN concentrations at SOE sites in the Karamū and Ahuriri catchments is shown in Figure 3-3.

Total phosphorus concentrations in the Karamū and Ahuriri catchments were very high and always above the lowland ANZECC trigger value of 0.033 mg/L at all sites except the Raupare Stream (Figure 3-2). Median TP concentrations were 5 times above the ANZECC trigger value in the Karewarewa, Awanui and Poukawa Streams, and the median concentrations in the Taipo Stream was more than 10 times the trigger value.

All Karamū and Ahuriri sites (except for the Raupare Stream) were amongst the ten sites with regionally highest TP concentrations. The Karewarewa and Awanui Streams were also amongst the 10 sites with regionally highest TN concentrations

A map of 5-year median TP concentrations at SOE sites in the Karamū and Ahuriri catchments is shown in Figure 3-4.

TN and TP highlights in the Karamū and Ahuriri catchments

• TN was above guideline levels at 5 out of 7 sites in the Karamū and Ahuriri catchments.

• TP was always above guideline levels at all sites. At some sites, median values reached 5- to 10-fold concentrations of the ANZECC trigger value.

• All Karamū and Ahuriri sites (except for the Raupare Stream) were amongst the 10 sites with regionally highest TP concentrations. The Karewarewa and Awanui Streams were also amongst the 10 sites with regionally highest TN concentrations.


Figure 3-1: Total Nitrogen (TN) levels at Karamū and Ahuriri SOE sites. SOE sites for the Mohaka River U/S Taharua confluence and the Ngaruroro River at Whanawhana (shaded) are included as Upland (U) and Lowland (L) reference sites for comparison. The blue line is (ANZECC, 2000) ‘Upland’ TN trigger value; the red line (ANZECC, 2000) ‘Lowland’ TN trigger value.


Figure 3-2: Total Phosphorus (TP) levels at Karamū and Ahuriri SOE sites. The blue line is (ANZECC, 2000) ‘Upland’ TP trigger value; the red line (ANZECC, 2000) ‘Lowland’ TP trigger value. SOE sites for the Mohaka River U/S Taharua confluence and the Ngaruroro River at Whanawhana (shaded) are included as Upland (U) and Lowland (L) reference sites for comparison.

Table 3-1 summarises the results of trend analyses carried out on TN and TP across all SOE monitoring sites of the Karamū and Ahuriri catchments over a 6-year period. For a full summary of trend analyses results refer to Appendix C. There were no significant trends apparent in the dataset for TN, but TP increased significantly in the Poukawa Stream at Pakipaki.

As already discussed in relation to trends in the Ngaruroro and Tūtaekurī catchments, climate could be a driver for observed trends, and an in-depth analysis with trend results including longer-term datasets and climate and land use data will be done in a separate trends report. Trend analysis started in a significant drought year (2012), and in the following years rainfall was lower than average. For the last two years of the trend analysis, rainfall was higher than average with severe storms and localised flooding.


Table 3-1: Trend analysis results for TN and TP at Karamū and Ahuriri SOE sites period 2012 to 2018. Includes only sites with sufficient data and monitoring length for trend analysis. In bold: significant trend when p < 0.05. Cells shaded blue for improving trend, red for deteriorating trend.

Site

Total Nitrogen Total Phosphorus



Karewarewa Strm 1.983 0.16 -6.83 0.159 0.07 -5.936 Awanui Strm 1.985 0.76 -1.255 0.2 0.90 -0.671 Poukawa Strm 1.435 1.00 0.26 0.172 0.01 8.136 Herehere Strm 0.485 0.24 3.63 0.074 0.20 4.883 Clive Rv 0.755 0.22 4.327 0.117 0.29 1.669 Taipo Strm 0.94 0.16 5.725 0.38 0.43 3.625


Figure 3-3: 5 year median TN levels at Karamū and Ahuriri SOE sites including trend direction. Arrows indicate direction of significant trends, with blue arrows for improvement and red arrows for deterioration. 6 years of record between 2012 and 2018 for trend analysis.


Figure 3-4: 5 year median TP levels at Karamū and Ahuriri SOE sites including trend direction. Arrows indicate direction of significant trends, with blue arrows for improvement and red arrows for deterioration. 6 years of record between 2012 and 2018 for trend analysis.


3.1.2 Dissolved Inorganic Nitrogen (DIN) and Dissolved Reactive Phosphorus (DRP)

Nutrient concentration patterns across study sites in the Karamū catchment and the Taipo in the Ahuriri catchment were similar for both total and dissolved nutrients (Figure 3-5 and Figure 3-6). Most samples from the Karewarewa and Awanui Streams were above DIN ANZECC lowland trigger values. Poukawa Stream had the lowest median DIN concentrations, with the majority of the samples below the lowland guideline.

DRP concentrations in the Karamū and Ahuriri catchments were high, and always above ANZECC trigger value levels at all SOE sites, in a similar pattern to TP concentrations. The Taipo Stream had the highest DRP concentrations - the median value of 0.250 mg/L is 16 times higher than the 0.015 mg/L trigger ANZECC lowland trigger value.

All Karamū and Ahuriri sites (except for the Raupare Stream) were amongst the 10 sites with the highest DRP concentration regionally.

Maps of 5-year median DIN and DRP concentrations at SOE sites in the Karamū and Ahuriri catchments are shown in Figure 3-7and Figure 3-8 respectively.

DIN and DRP highlights in the Karamū and Ahuriri catchments

• Median DIN concentrations were variable among sites, with some sites significantly above ANZECC trigger values (Karewarewa, Awanui), and others generally below (Herehere, Poukawa).

• DRP concentrations were always above ANZECC trigger values at all sites, and up to 16 times above the trigger value in the Taipo Stream.

• The Karamū and Ahuriri SOE sites (except for the Raupare Stream) were amongst the 10 sites with regionally highest DRP concentrations.


Figure 3-5: Dissolved inorganic nitrogen (DIN) levels at Karamū and Ahuriri SOE sites. The blue line is the (ANZECC, 2000) ‘Upland’ DIN trigger value; the orange line is the Biggs (2000) suggested limit for DIN for periphyton growth management for a 20-day accrual period; the red line is the (ANZECC, 2000) ‘Lowland’ DIN trigger value. SOE sites for the Mohaka River U/S Taharua confluence and the Ngaruroro River at Whanawhana (shaded) are included as Upland (U) and Lowland (L) reference sites for comparison.

Dissolved nutrients DIN and DRP did not show any significant trends at most SOE monitoring sites in the Karamū and Ahuriri catchments (Table 3-2), but DRP in the Poukawa and Herehere Streams increased significantly over the 6-year period. This is consistent with a significant increase in TP concentration in the Poukawa. As already discussed in relation to trends in the Ngaruroro and Tūtaekurī catchments, climate could be a driver for observed trends, and an in-depth analysis with trend results including longer-term datasets and climate and land use data will be done in a separate trends report. Trend analysis started in a significant region-wide drought year (2012), and in the following years rainfall was lower than average. For the last two years of the trend analysis, rainfall was higher than average with severe storms and localised flooding.


Figure 3-6: Dissolved reactive phosphorus (DRP) levels at Karamū and Ahuriri SOE sites. The blue line is the (ANZECC, 2000) ‘Upland’ DRP trigger value; the red line is the (ANZECC, 2000) ‘Lowland’ DRP trigger value and the Biggs (2000) suggested limit for DRP for periphyton growth management for a 20-day accrual period. SOE sites for the Mohaka River U/S Taharua confluence and the Ngaruroro River at Whanawhana (shaded) are included as Upland (U) and Lowland (L) reference sites for comparison.

Table 3-2: Trend analysis results for DIN and DRP at Karamū and Ahuriri SOE sites period 2012 to 2018. Includes only sites with sufficient data and monitoring length for trend analysis. In bold: significant trend when p < 0.05. Cells shaded blue for improving trend, red for deteriorating trend. Refer to Appendix C for a full breakdown of trend analysis results.

Site

DIN DRP



Karewarewa Strm 1.349 0.52 -3.299 0.125 0.06 -6.289 Awanui Strm 1.09 0.71 -2.332 0.169 0.58 -3.039 Poukawa Strm 0.117 0.10 -8.682 0.143 0.01 10.08 Herehere Strm 0.127 1.00 -0.099 0.062 0.05 6.643 Clive Rv 0.43 0.72 0.051 0.095 0.52 1.946 Taipo Strm 0.356 0.90 -0.188 0.25 0.59 1.542


Figure 3-7: 5 year median DIN levels at Karamū and Ahuriri SOE sites including trend direction. Arrows indicate direction of significant trends, with blue arrows for improvement and red arrows for deterioration. 6 years of record between 2012 and 2018 for trend analysis.


Figure 3-8: 5 year median DRP levels at Karamū and Ahuriri SOE sites including trend direction. Arrows indicate direction of significant trends, with blue arrows for improvement and red arrows for deterioration. 6 years of record between 2012 and 2018 for trend analysis.


3.2 Nitrate-nitrogen and ammoniacal-nitrogen toxicity

NOF bands for nitrate and ammonia toxicity are shown in Table 3-3. The different thresholds are associated with specific sample statistics to reflect different timescales of effect:

• The sample median manages exposure under ‘average’ conditions in nitrate and ammonia concentrations.

• The 95th percentile (nitrate) manages exposure during seasonal peaks in nitrate concentrations.

• The maximum (ammonia) manages exposure during critical events and daily or seasonal peaks in ammonia concentrations.

Table 3-3: NPS-FW (2014) NOF band summary for freshwater river attributes at Karamū and Ahuriri SOE sites for the period 2013 to 2018.

Site Nitrate (toxicity) Ammonia (toxicity)

Median 95th percentile Median Maximum

Karewarewa Strm B C A B Awanui Strm B C A B Poukawa Strm A B A A Herehere Strm A C A B Raupare Dr A C A B Clive Rv A C A B Taipo Strm A B A C

For narrative descriptions of the NOF bands refer to Appendix E. Median nitrate-nitrogen concentrations were in the A band for most of the Karamū catchment sites except Karewarewa and Awanui Streams, and median ammonia concentrations were in the A band at all sites. The sample median in the A band reflects a low level of risk from nitrate or ammonia toxicity to any aquatic species under average conditions. Regarding

Nitrate-nitrogen and ammoniacal-nitrogen highlights in the Karamū and Ahuriri catchments

• At all sites, under average conditions, species protection was in the NOF A Band (99% species protection) or B Band (95% species protection) for both ammonia and nitrate toxicity.

• Nitrate toxicity effects of short-term peaks and critical events were in the C Band (80% species protection) at most sites.

• In most streams nitrate peaks causing exceedance into the C Band were rare (in one out of 5 monitored years). By contrast, the Raupare and Karewarewa streams were in the C band in 2 and 3 years out of 5, respectively.

• For ammonia peaks, only the Taipo Stream was in the C band; all other sites were in the A or B band.


short-term exposure to daily or seasonal peaks (95th percentile for nitrate and maximum for ammonia) only the Poukawa Stream fell into the A band for ammonia under both average and peak conditions. All other sites are likely to have some growth effect on up to 5% of species (B band) or growth effects on up to 20% of mainly sensitive species (C band), but no acute effects, due to short-term exposure to nitrate or ammonia.

Most streams fell into the C band for nitrate toxicity in one (2017) out of 5 monitored years (Appendix F). By contrast, the Raupare and Karewarewa streams were in the C band in 2 and 3 years out of 5, respectively. Only the Taipo Stream was in the C band for ammonia toxicity, and exceeded into this band in 2 out of 5 years (Appendix F).

The 5-year nitrate-nitrogen concentrations in the Karamū catchment can be seen in Figure 3-9. The Karewarewa and Awanui Streams had the highest median nitrate concentrations and the highest nitrate peaks (95th percentiles), which indicates that in these streams there was a higher risk for sensitive aquatic organisms to experience for example some growth effects compared to the other sites.

Figure 3-9: Nitrate-nitrogen (NO3-N) levels at Karamū and Ahuriri SOE sites. The lines are the NPS-FM (MfE, 2017) nitrate toxicity thresholds for 99% species protection (A/B threshold, blue), and 95% species protection (B/C threshold, yellow). The continuous line is related to the annual median at the sites (the line in the blue boxes). The dotted line is related to the 95th percentile of the data at the sites (the whisker). SOE sites for the Mohaka River U/S Taharua confluence and the Ngaruroro River at Whanawhana (shaded) are included as Upland (U) and Lowland (L) reference sites for comparison.


Trend analysis over the 6-year period 2012 to 2018 showed a significant decrease in ammoniacal-nitrogen in the Karewarewa and Awanui streams (Table 3-4).

Table 3-4: Trend analysis results for nitrate-nitrogen (NO3-N) at Karamū and Ahuriri SOE sites period 2012 to 2018. Includes only sites with sufficient data and monitoring length for trend analysis. In bold: significant trend when p < 0.05. Cells shaded blue for improving trend, red for deteriorating trend. Refer to Appendix C for a full breakdown of trend analysis results.

Site

Nitrate Ammoniacal-N



Karewarewa Strm 1.27 0.77 -0.239 0.043 0.00 -23.933 Awanui Strm 0.995 1.00 0 0.04 0.00 -20.845 Poukawa Strm 0.078 0.07 -2.579 0.005 0.01 0 Herehere Strm 0.105 0.60 1.419 0.005 0.08 0 Clive Rv 0.365 0.72 0.29 0.027 0.66 0 Taipo Strm 0.132 0.90 0 0.082 0.38 0

A map of 5-year median nitrate-N concentrations at SOE sites in the Karamū and Ahuriri catchments is shown in Figure 3-10.


Figure 3-10: 5 year median nitrate-nitrogen levels at Karamū and Ahuriri SOE sites including trend direction. Arrows indicate direction of significant trends, with blue arrows for Nitrate-improvement and red arrows for deterioration. 6 years of record between 2012 and 2018 for trend analysis.


3.3 Water Clarity – Black disc and turbidity For background information on water clarity and turbidity refer to section 2.3.

Black disc water clarity is inversely related to turbidity. Turbidity is a measurement of the degree of light scattering caused by suspended particles in the water column. The greater the concentration of suspended particles, the higher the turbidity. At very low turbidity levels a small increase in turbidity results in a large decrease in black disc.

Black disc clarity and turbidity in the Karamū catchment at all flows are shown in Figure 3-11 and Figure 3-12.

Median black disc clarity ranged from 0.4 m (Taipo Stream) to 2.3 m (Herehere Stream). Visual clarity for contact recreation was only met in the Poukawa, Herehere and Raupare streams, all other SOE sites were not meeting the guideline of at least 1.6 m viewing distance.

The Clive River had a 5-year median clarity of 0.8 m at all flows, and does not meet the ANZECC contact recreation guideline and RRMP recreational amenity guideline of 1.6 m. The median clarity at less than median flows (Appendix A) was 1.6 m at the site, and just meets the recreational guideline.

Turbidity at the SOE sites in the Karamū and Ahuriri catchments is shown in Figure 3-12. Median turbidity at were below ANZECC lowland trigger value of 5.6 NTU all sites except for the Taipo.

The Taipo Stream had the lowest black disc clarity, and highest turbidity, of any SOE site in the region (Appendix D). The Karamū SOE sites were around the regional average in both clarity and turbidity.

Maps of 5-year median water clarity and turbidity levels at SOE sites in the Karamū and Ahuriri catchments are shown in Figure 3-13 and Figure 3-14 respectively.

Water clarity highlights in the Karamū and Ahuriri catchments

• Clarity: The Taipo, Awanui and Clive SOE sites did not meet the 1.6 m clarity contact recreation guideline.

• Turbidity: All sites except for the Taipo are better than the lowland ANZECC trigger level.

• In the Taipo Stream, black disc clarity was lowest and turbidity highest regionally.


Figure 3-11: Water clarity measured as black disc horizontal sighting distance for Karamū and Ahuriri SOE sites. The blue line is the Hay and Hayes (2006) ‘Outstanding trout fishery’ limit; the orange line the ‘Significant trout fishery’ limit. The red line is the (ANZECC, 2000)/ HBRC RRMP 2006 recreational amenity limit. SOE sites for the Mohaka River U/S Taharua confluence and the Ngaruroro River at Whanawhana (shaded) are included as Upland (U) and Lowland (L) reference sites for comparison.


Figure 3-12: Water clarity measured as turbidity (NTU) for Karamū and Ahuriri SOE sites. The blue line is (ANZECC, 2000) ‘Upland’ TN trigger value; the red line to (ANZECC, 2000) ‘Lowland’ TN trigger value. SOE sites for the Mohaka River U/S Taharua confluence and the Ngaruroro River at Whanawhana (shaded) are included as Upland (U) and Lowland (L) reference sites for comparison There were no significant trends in black disc clarity or turbidity over the 6-year period from 2012 to 2018 (Table 3-5).


Table 3-5: Trend analysis for black disc clarity and turbidity at Karamū and Ahuriri SOE sites period 2012 to 2018. Includes only sites with sufficient data and monitoring length for trend analysis. In bold: significant trend when p < 0.05. Cells shaded blue for improving trend, red for deteriorating trend.

Site

Black Disc Turbidity



Karewarewa Strm 1.6 0.32 5.853 2.56 0.25 -6.22 Awanui Strm 1.25 0.72 -4.212 2.495 0.31 -4.63 Poukawa Strm 1.88 0.12 12.561 1.46 0.49 -3.106 Herehere Strm 2.3 0.10 5.818 1.835 0.12 -8.151 Clive Rv 1.125 0.77 -2.133 3.09 0.25 -3.28 Taipo Strm 0.4 0.27 -24.06 12 0.67 9.368


Figure 3-13: 5 year median black disc levels at Karamū and Ahuriri SOE sites including trend direction. Arrows indicate direction of significant trends, with blue arrows for improvement and red arrows for deterioration. 6 years of record between 2012 and 2018 for trend analysis.


Figure 3-14: 5 year median turbidity levels at Karamū and Ahuriri SOE sites including trend direction. Arrows indicate direction of significant trends, with blue arrows for improvement and red arrows for deterioration. 6 years of record between 2012 and 2018 for trend analysis.


3.4 Bacteriological water quality – E. coli For background information on bacteriological water quality refer to section 2.4.

Figure 3-15 shows E. coli levels at all flows in the Karamū and Ahuriri catchments compared to recreational guidelines of MfE and MoH (2003). At all sites (except the Poukawa stream) bacteria concentrations reached the red/action level at times. The highest E.coli concentrations were found in the Herehere and Taipo streams, where most of the samples were in the red/action mode, which means these sites would have frequently been unsafe for contact recreation according to national guidelines.

A map of 5-year median E.coli concentrations at SOE sites in the Karamū and Ahuriri catchments is shown in Figure 3-16.

Bacteriological water quality highlights in the Karamū and Ahuriri catchments

• Only the Poukawa Stream was graded swimmable in the NPS-FM framework. All other Karamū and Ahuriri SOE sites have E. coli concentrations categorised as not suitable for primary contact recreation.

• High E. coli concentrations were not limited to high flow events after rainfall. The sites were also graded not swimmable under average flow conditions.

• Six Karamū and Ahuriri SOE sites were amongst the 8 sites with highest median E. coli concentrations regionally.

• A faecal source tracking study is underway to identify the sources of bacteria in the Karamū and Ahuriri catchments.


Figure 3-15: Bacteriological water quality levels measured as E. coli counts (cfu/100ml) at Karamū Stream and Ahuriri Estuary SOE monitoring sites. SOE sites for the Mohaka River U/S Taharua confluence and the Ngaruroro River at Whanawhana (shaded) are included as Upland (U) and Lowland (L) reference sites for comparison. The blue line is the MfE and MoH (2003) amber alert level; the red line the MfE and MoH (2003) red alert level. The NPS-FM (MfE, 2017) requires councils to set a freshwater objective for E. coli in all rivers. The E. coli attributes of the NPS-FM are explained in the Guide to Attributes report (MfE, 2018) and more detailed context is given in Chapter 2.4. The overall grade as shown in Table 3-6 must satisfy 4 criteria of numeric attribute states in the same band, consisting of different statistics. These 4 statistical measures show the distribution of E. coli concentrations and the associated risk of Campylobacter infection through ingestion of water during recreation activities (McBride, 2012); (MfE and MoH, 2003). Overall bands A, B and C are categories considered suitable for primary contact recreation.


Table 3-6: NPS-FM bands (MfE, 2018, MfE, 2017) for E.coli at the Karamū and Ahuriri SOE sites. Monitoring period 2013 to 2018. Overall grade must satisfy all 4 criteria of numeric attribute states in the same band (Appendix E). No 95th percentile: Top range of E.coli levels excluded. Overall grade A, B and C bands are categories suitable for primary contact recreation. Sites marked with * are short-term monitoring sites (data records of 3 years), excluded from E.coli attribute analysis.

Site E. coli

Overall grade

No 95th percentile

Karewarewa Strm E E Awanui Strm E E Poukawa Strm B B Herehere Strm E E Raupare Dr E E Clive Rv D D Taipo Strm E E

Only one site in the Karamū catchment, the Poukawa Stream (B band), would be suitable for primary contact recreation (Table 3-6). All other sites are unsuitable for contact recreation: The Clive River site is graded in the D Band, and all others are in the E Band. For the sites in the E Band this means that for more than 30% of the time, the estimated infection risk is ≥50 in 1000 people involved in full immersion activities such as swimming. The predicted average infection risk is >7%. In the Clive River (D Band) for at least 20-30% of the time, the estimated infection risk is ≥50 in 1000 people involved in full immersion activities such as swimming. The predicted average infection risk is >3%. The actual risk of an infection will generally be less if a person does not swim during high flows. The difference can be seen when taking out the top range of E. coli, i.e. the 95th percentile (Table 3-6): if these E. coli peaks occur during and directly after rainfall events at high flows only, then the infection risk could be lower at times when swimming often occurs, i.e. in summer at lower flows. But in the case of the Karamū and Ahuriri catchments, the ranking remains the same even when taking out the 95th percentile range of E. coli, and high E. coli concentrations also occur at less than median flows (for flow related statistics see Appendix B).

The 6 Karamū and Ahuriri SOE sites (not the Poukawa Stream) were amongst the 8 sites with regionally highest median E. coli concentrations.

A study is underway to identify the sources of bacteria by using genetic faecal source tracking. This method identifies whether the bacteria originate from ruminant, avian, human or other sources.

There were no significant trends in the Karamū catchment and Ahuriri estuary sites for the 6-year time period (Table 3-7), although the Poukawa and Taipo Streams had marginally non-significant increases of between 8-10% per year (p=0.06 for both).


Table 3-7: Trend analysis results for E. coli for SOE monitoring sites at Karamū and Ahuriri SOE sites. (Includes only sites with sufficient data and monitoring length for trend analysis. In bold: significant trend when p < 0.05. Cells shaded blue for improving trend, red for deteriorating trend.

Site

E. coli


Karewarewa Strm 300 0.19 -7.302 Awanui Strm 250 0.85 2.996 Poukawa Strm 130 0.06 8.004 Herehere Strm 600 0.53 5.395 Clive Rv 230 0.16 8.586 Taipo Strm 1050 0.06 9.789


Figure 3-16: 5 year median E.coli levels at Karamū and Ahuriri SOE sites including trend direction. Arrows indicate direction of significant trends, with blue arrows for improvement and red arrows for deterioration. 6 years of record between 2012 and 2018 for trend analysis.


3.5 Dissolved oxygen An introduction on the role of dissolved oxygen (DO) in the aquatic environment is given in Chapter 2.5.

In unshaded streams with high nutrient inputs, excessive growth of plants and algae results in extremely high DO levels during the day, then extremely low DO levels during the night or early morning, when these plants and algae consume more oxygen than the waterway is capable of supplying. The low DO conditions mean there is little oxygen for fish and other organisms.

In the SOE programme DO was only assessed as spot measurements on the sampling day. There are limitations in the value of spot measurements of DO, as they do not capture the full extent of daily DO fluctuation. Nevertheless the results of the spot measurements shown in Figure 3-17 and Figure 3-18 show a high variability in DO at most Karamū and Ahuriri catchment SOE sites. DO greater than 100% (supersaturation) generally indicates high photosynthetic activity by aquatic plants, and therefore a risk of critically low oxygen at night, even if the entire DO range is not captured.

Based on SOE spot measurements, dissolved oxygen concentration (Figure 3-17) was generally above, and therefore better than the ANZECC minimum DO guideline of 6 mg/L in the Herehere, Raupare, Awanui streams and in the Clive River. The Poukawa Stream had the lowest oxygen levels, with a median DO of 5.6 mg/L, which was below the ANZECC guideline.

DO saturation (Figure 3-18) follows the same pattern as DO concentration, and the DO median complied with the 80% RMA guideline for protecting trout fisheries in the Herehere, Raupare and Awanui streams and in the Clive River during daytime when spot measurements were taken. The median DO saturation in the Karewarewa Stream was at the threshold of 80%, and DO saturation samples taken in the Poukawa and the Taipo streams were more often below 80% than above. The Poukawa and Taipo, but also the Karewarewa and Awanui streams showed very low oxygen levels in some spot measurements, which indicates that during night time severely low oxygen levels are likely to occur.

Maps of 5 year median DO saturation and concentration at SOE sites in the Karamū and Ahuriri catchments are shown in Figure 3-19 and Figure 3-20 respectively.

Dissolved oxygen highlights in the Karamū and Ahuriri catchments

• The sites most at risk for critically low oxygen levels were the Karewarewa, Awanui, Taipo and Poukawa Streams.

• Oxygen levels in the Karewarewa, Awanui, Taipo are most likely driven by excessive aquatic plant growth.

• DO in the Poukawa Stream was below guideline levels at all times. This could indicate high microbial breakdown rates of organic material, and less influence of aquatic plant respiration on oxygen levels.


Figure 3-17: Dissolved oxygen concentration at Karamū and Ahuriri SOE sites. The red line is the ANZECC (1992) guideline minimum DO concentration of 6 mg/L. SOE sites for the Mohaka River U/S Taharua confluence and the Ngaruroro River at Whanawhana (shaded) are included as Upland (U) and Lowland (L) reference sites for comparison.

Sites with oxygen supersaturation (DO > 100%) can indicate high aquatic plant and algal oxygen production during daytime, which means that critically low oxygen concentrations could occur during the night or early morning hours, when plants only respire and don’t produce any oxygen. By contrast daytime spot samples in the Poukawa Stream were generally low in oxygen, which can be an indication for a high amount of organic matter that gets broken down: the high metabolic activity uses up more oxygen than is produced by plants or algae at the same time. During night time low oxygen levels can be even more severe than during daytime in such cases. In the Poukawa stream the low oxygen levels could also reflect the influence of the wetland that is located upstream of the sampling site.


Figure 3-18: Dissolved oxygen saturation at Karamū and Ahuriri SOE sites. The red line is the RMA (1991) Schedule 3 lower limit of 80% for supporting salmoniid (trout) fisheries. SOE sites for the Mohaka River U/S Taharua confluence and the Ngaruroro River at Whanawhana (shaded) are included as Upland (U) and Lowland (L) reference sites for comparison.

The spot measurements indicate there was a risk of oxygen problems at many sites. The Karewarewa, Awanui, Poukawa, Herehere and Taipo streams were part of a study of 16 sites with continuous 24-hour oxygen measurements during a warm, dry summer period in February 2014 (Haidekker, 2016). The Awanui Stream experienced complete oxygen depletion, and the minima for Karewarewa, Poukawa and Taipo streams ranged between 8% and 14% DO. At night these streams reach critically low DO conditions that put aquatic organisms at risk. Only the Herehere Stream always had oxygen concentrations above 50%.


Figure 3-19: 5 year median DO saturation at Karamū and Ahuriri SOE sites including trend direction. Arrows indicate direction of significant trends, with blue arrows for improvement and red arrows for deterioration. 6 years of record between 2012 and 2018 for trend analysis.


Figure 3-20: 5 year median DO concentration at Karamū and Ahuriri SOE sites including trend direction. Arrows indicate direction of significant trends, with blue arrows for improvement and red arrows for deterioration. 6 years of record between 2012 and 2018 for trend analysis.


3.6 Biological indicators

3.6.1 Periphyton and Macrophyte biomass and cover

Streams in the Karamū catchment originate from lowland country in a warm dry climate, according to the New Zealand River Environment Classification REC (Snelder et al., 2010). Most streams in the catchment have very low gradients and flow slowly, on fine gravel or sandy/silty streambeds. This provides ideal growing conditions for aquatic plants, which are true ‘vascular’ plants and are comparable to their terrestrial relatives (by contrast, algae lack true roots, stems and leaves). Under natural conditions aquatic plants, also called macrophytes, are important habitat for macroinvertebrates and fish in soft sediment streams, where stable habitat is scarce.

As with algae, macrophytes can grow to nuisance levels in summer, when growth rates peak. Macrophytes in high abundance can detrimentally affect ecological health by (a) affecting in-stream DO levels through photosynthetic and respiration processes, (b) by reducing flow conveyance, and (c) by detrimentally affecting aesthetic and recreational values. In addition, consumption of inorganic carbon during photosynthesis results in changes to the equilibrium balance of carbonate/bicarbonate/carbonic ions and can lead to marked diurnal fluctuations in pH.

At most SOE sites in the Karamū and Ahuriri catchments, macrophytes were the predominant primary producers. By contrast, only the Herehere and Karewarewa SOE sites have a significant proportion of hard streambed substrate where periphyton grows at times. The role of algae in streams and rivers, the definition of periphyton, and the visual assessment of algae is explained in greater detail in Chapter 2.6.1.

Monitoring for macrophyte abundance started in 2013 when a suitable monitoring protocol became available. Provisional guidelines are suggested as ≤ 50% cover for the cross-sectional area/volume (CAV) with the purpose of protecting ecological conditions, flow conveyance and recreation, and ≤ 50% surface area (SA) for aesthetics and recreation (Matheson et al., 2012). Matheson et al. (2012) stress that only sparse information exists on the relationship between in-stream macrophyte abundance and detrimental impacts on key in-stream values, and further research is needed.

Periphyton was only assessed at sites in the Karamū catchment that have a significant proportion of hard streambed substrate - the Herehere and Karewarewa Streams. Both streams are highly productive, and the

Macrophyte highlights in the Karamū and Ahuriri catchments

• The Karewarewa, Awanui, Raupare and Poukawa streams had particularly high macrophyte biomass which exceeded the guideline for protecting the ecological condition, flow conveyance and recreation.

• The Karewarewa was highly productive in both macrophytes and periphyton, and changed between 80% macrophyte volume and up to 70% algal cover (PeriWCC) in different years.

• The Taipo Stream had nuisance macrophyte biomass at times, but macrophytes are sprayed or cut regularly. Macrophyte volume ranged from 0% to 100% between different years.

• There is a probable link between problematic dissolved oxygen fluctuations and excessive macrophyte growth.


proportional cover of periphyton and macrophytes at these sites varies greatly from year to year, to the point that sometimes only algae or only macrophytes are present. The Herehere Stream had high algal cover in summer 2013/14 reaching a PeriWCC of 90%, and in spring 2017 a PeriWCC of 80%. A PeriWCC of greater than 55% is indicative of poor ecological condition. The Karewaewa stream had an algal cover of up to 70% PeriWCC in the summer 2013/14.

Figure 3-21 shows macrophyte abundance measured as cross-sectional area/volume (CAV) and surface area (SA) at 6 SOE sampling sites in the Karamū and Ahuriri catchments. Macrophyte abundance was highest in the Karewarewa, Awanui and Poukawa Streams, and these sites exceeded the proposed guideline for CAV of 50% to protect ecological conditions, flow conveyance and recreation. The guideline of 50% SA for recreation and aesthetical values was exceeded in the Karewarewa, Awanui, Poukawa and Raupare Streams. The low macrophyte abundance in the Taipo Stream may not be expected given the high nutrient availability and ideal growing conditions. The Taipo Stream has nuisance macrophyte biomass at times, but the stream flows through an urban area and macrophytes are sprayed or cut regularly. Assessment results ranged from 0% to 100% macrophyte volume. The dissolved oxygen levels in the Taipo, discussed in Chapter 3.5, were reflective of the highly disturbed system, at times supersaturated with DO, and severely low oxygen levels, that may also be caused by disintegrating plant matter.

Figure 3-21: Macrophyte abundance at Karamū and Ahuriri SOE sites. Cross-sectional area/volume (CAV) is the proportional volume occupied by macrophytes in a stream cross section, median of annual maxima over 5 years monthly monitoring. Surface area (SA) mean is the proportional stream surface area covered by macrophytes, averaged over 5 transects. Grey line is the provisional guideline as proposed in Matheson et al. (2012).


3.6.2 Macroinvertebrate Community Index Background on the macroinvertebrate community index (MCI) is given in Chapter 2.6.2.

MCI scores for the Karamū and Ahuriri catchments SOE monitoring sites showed macroinvertebrate communities were in poor condition throughout the SOE sites (Figure 3-22 and Figure 3-23). The MCI indicated poor water quality, with probable severe pollution.

The Clive River and the Herehere, Karewarewa and Taipo Streams ranked lowest compared to all other SOE sites in Hawke’s Bay with MCI scores of less than 70. The Raupare, Poukawa and Awanui streams were also among the 10 lowest MCI scores regionally.

EPT taxa (Ephemeroptera - mayflies, Plecoptera - stoneflies, and Trichoptera - caddisflies) are mostly pollution sensitive taxa that indicate good water quality when present in higher proportions in a macroinvertebrate community. The proportion of EPT taxa in the macroinvertebrate community at SOE sites are in Appendix B in the column ‘%EPT taxa’. At sites with a healthy macroinvertebrate community, about half of the taxa present would be sensitive EPT taxa, and at pristine sites the proportion can be over 75% (e.g. Tūtaekurī at Lawrence Hut). The macroinvertebrate community in the Ngaruroro River at Whanawhana (lowland reference site) consisted of 53% EPT taxa. At all Karamū catchment sites the EPT taxa comprised less than 5% of the macroinvertebrate community, and in many samples no EPT taxa were present. This indicates that stream health was severely compromised, with low life-supporting capacity, because all sensitive taxa had been lost from these sites.

A study suggested multiple stressors compromise life-supporting capacity in the Karamū and Ahuriri catchments, with the main factors being high water temperatures, severe oxygen minima, and lack of habitat (Haidekker, 2016). Riparian planting to provide shade to protect streams from high water temperatures and to slow down macrophyte growth to mitigate oxygen minima is a key management option to improve ecosystem health in these catchments (Matheson et al., 2017).

MCI highlights in the Karamū and Ahuriri catchments

• All sites in the Karamū and Ahuriri catchments had poor MCI scores indicative of severely compromised ecosystem health.

• All 7 sites ranked amongst the 10 sites with lowest MCI scores regionally.

• All sites had less than 5% sensitive EPT taxa on average, with many samples without a single EPT taxon.

• Improving ecosystem health was identified as a high priority for the Karamū and Ahuriri catchments.


Figure 3-22: MCI levels at Karamū and Ahuriri SOE sites. The lines are boundaries between MCI quality classes as defined by Stark and Maxted (2007): Blue line: boundary between classes excellent and good, orange line: boundary between classes good and fair, red line: boundary between classes fair and poor. SOE sites for the Mohaka River U/S Taharua confluence and the Ngaruroro River at Whanawhana (shaded) are included as Upland (U) and Lowland (L) reference sites for comparison.


Figure 3-23: 5 year median MCI levels at Karamū and Ahuriri SOE sites including trend direction. Arrows indicate direction of significant trends, with blue arrows for improvement and red arrows for deterioration. 6 years of record between 2012 and 2018 for trend analysis..


3.6.3 Physical Habitat

As explained in Chapter 2.6.3 in more detail, physical habitat is the living space of aquatic flora and fauna, and it is a critical component of good stream health (Shields et. al. 2006; Clapcott et. al. 2018). In general, a more diverse habitat will support a more diverse range of flora and fauna (Benton et. al. 2003). Degradation of physical habitat in rivers and streams has been widespread in rural and urban areas alike (Reid et. al. 2008; Quinn et. al. 2010).

Most sites in the Karamū catchment had poor physical habitat condition (Figure 3-24). The Taipo Stream had a RHA score of 24, which was one of the lowest scores in Hawke’s Bay. The Awanui and Raupare Streams and the Clive River scored well below the national lower quartile of (Clapcott 2015).

Moderate amounts of macrophytes in soft sediment streams provide potential habitat for macroinvertebrate and fish, but habitat heterogeneity and the riparian condition scored very poorly across all Karamū catchment sites except for the Herehere. The Herehere, Karewarewa, Poukawa and Raupare Streams had better habitat diversity for macroinvertebrates than the other sites. Nevertheless MCI scores for all of these sites were very poor, showing that instream habitat is not the only stressor. If shade from riparian vegetation is established then other stressors like high water temperature and low oxygen are expected to be reduced, and the overall improvement to ecosystem health should result in healthier macroinvertebrate communities in the future.

Habitat highlights in the Karamū and Ahuriri catchments

• Most sites in the Karamū catchment had poor physical habitat condition.

• The Taipo Stream had a RHA score of 24, which is one of the lowest scores in Hawke’s Bay.

• Habitat heterogeneity and the riparian condition scored very poorly across all sites except for the Herehere.


Figure 3-24: Rapid Habitat Assessment score (RHA score) at Karamū and Ahuriri River SOE monitoring sites. The lines are thresholds for ecological condition. The lines are 25th percentile = 47, median = 63, and 75th percentile = 75, of the distribution of 560 New Zealand sites (Clapcott 2015). SOE sites for the Mohaka River U/S Taharua confluence and the Ngaruroro River at Whanawhana (shaded) are included as Upland (U) and Lowland (L) reference sites for comparison.


3.7 Stormwater One value of the Karamū Stream and the Ahuriri Estuary is to buffer stormwater discharges from the wider catchment and thereby prevent flooding and associated social and economic costs.

Stormwater consists of excess rainwater that does not infiltrate the ground. During the transition from pervious vegetated catchments to more impervious urbanised areas, stormwater has less opportunity for infiltration, and consequently higher overland flows occur due to increased runoff.

Unless treated, stormwater runoff carries associated contaminants into the ultimate receiving environments. Such contaminants can include trace metals, hydrocarbons, bacteria, sediments, organics, nutrients and gross litter which are entrained as the stormwater is diverted from roads, footpaths and property into roadside drains and underground networks. Industrial areas can also contribute metals and hydrocarbons from specific industry practise. As urbanisation increases, the speed with which stormwater reaches the receiving environment increases, and subsequently the quality of stormwater decreases due to the lack of ability for contaminants to settle out.

Of the 4 TANK catchments, only the Ahuriri and Karamū catchments have relatively high proportions of urban/industrial land-use that contribute to increased stormwater loading. In Ahuriri approximately 18% of the catchment is urbanised, with a large portion of the Napier City area diverting stormwater into the Ahuriri Estuary at the Westshore tide gates.

In the Karamū catchment, the city of Hastings discharges most of its stormwater into tributaries of the Karamū Stream such as the Ruahapia, Irongate, and Raupare Streams.

The urban streams of the Karamū catchment - and the estuarine environment associated with stormwater in the Ahuriri catchment - tend to be highly sensitive to the effects of stormwater-derived contaminants. They are often the immediate receiving environments for stormwater, with limited attenuation potential prior to the discharge point. They can also have multiple discharge points into the streams and so are sensitive to the cumulative effects of the catchment load.

Common sources of stormwater derived contaminants are described below (Table 3-8).

Table 3-8: Sources of stormwater derived contaminants that may affect values associated with the Karamū and Ahuriri receiving environments.

Contaminant Value affected Source

Trace Metals Ecological integrity, food gathering Roofing, plumbing, industry, garden sprays, vehicles, atmospheric deposition.

Bacteria Contact recreation, food gathering Wastewater infiltration, animal wastes.

Polycyclic Aromatic Hydrocarbons

Ecological integrity, recreation, amenity Organic compounds produced by incomplete combustion or pressure (e.g. industrial, vehicles, fuels etc.).

Nutrients Ecological integrity, recreation, amenity E.g. Nitrogen, phosphorus from fertilisers, detergents, plant debris.

Suspended Sediments Ecological integrity, recreation, amenity Erosion


Contaminant Value affected Source

Gross pollutants (litter) Ecological integrity, recreation, amenity Litter

Information on consented stormwater discharges in the Ahuriri and Karamu catchments, and monitoring results of several studies on trace metal and PAH concentrations in water and sediments are summarised in the TANK SOE report (Haidekker et al., 2016). Napier City Council and Hastings District Council are the territorial authorities dealing with stormwater consents. Napier City Council is currently implementing a programme to manage stormwater issues.


3.8 Summary and conclusion for the Karamū and Ahuriri catchments

The results of water quality and ecology SOE assessments in the Karamū and Ahuriri catchments show streams are highly compromised in terms of ecosystem health and life supporting capacity. Overall, the condition at SOE water quality and ecology sites in the Karamū and Ahuriri catchments ranked poorest of Hawke’s Bay in many factors. Most sites in the Karamū had amongst the highest concentrations of nutrients and E. coli, and lowest MCI and habitat scores, of all sites in Hawke’s Bay.

Nutrient concentrations were generally high at the Karamū and Ahuriri SOE sites. Nitrogen (TN and DIN) concentrations were variable between sites, with some sites up to 10-fold above trigger values and others generally below. Phosphorus (TP and DRP) concentrations were always above ANZECC trigger values at all sites: up to 16-fold the guideline concentration.

Ammonia and nitrate toxicity effects were likely to be minimal under average, long-term conditions (NOF band A and B, 99% and 95% species protection respectively). Most sites showed some probability of nitrate toxicity effects of short-term peaks and critical events, and were in NOF band C (80% species protection). Ammonia toxicity effects for peak ammonia concentrations were in the A or B band for most sites except the Taipo Steam (C band).

Bacteriological water quality in the Karamū and Ahuriri catchments showed that SOE sites have E. coli concentrations categorised as not suitable for primary contact recreation (except for the Poukawa Stream). High E. coli concentrations were not limited to rainfall and subsequent high flow events. The sites were also graded not swimmable under average flow conditions.

Several SOE sites were at risk for having critically low oxygen levels that are likely to stress fish, invertebrates and other aquatic organisms. Excessive macrophyte growth is contributing to this at most sites, and breakdown of organic matter may be another cause for low oxygen levels.

Biological indicators showed that most SOE sites were highly compromised. The macroinvertebrate community was in a poor condition at all sites. There was excessive macrophyte growth at most sites with adverse effects on water quality, particularly dissolved oxygen. Physical habitat was poor at most Karamū and Ahuriri SOE sites, particularly in terms of habitat heterogeneity and riparian condition.

The Taipo, Awanui and Karewarewa Streams were the most compromised streams in the Karamū and Ahuriri catchments.

The poor ecosystem condition and life supporting capacity in these catchments was highlighted in the previous SOE technical report 2009-13. An investigation followed to identify the main stressors on the ecosystem health (Haidekker, 2016). High water temperature, low dissolved oxygen levels and poor habitat conditions were found to be the main stressors. A workshop held with HBRC staff and external freshwater scientists from different research institutes (Matheson et al., 2017) recognised riparian vegetation to be the best option to achieve long-term improvement of ecosystem health in the lowland catchments. Riparian plants that shade streams protect water from getting too warm in summer, reduce macrophyte growth, which also improves dissolved oxygen levels, and provide habitat. Riparian management could also help to stabilise stream banks and play a role as a filter for sediment and E. coli.


Nutrient concentrations were also very high in the Karamū and Ahuriri Streams. While a reduction in nutrient concentrations is not likely to achieve a significant reduction in macrophyte growth, nutrient loads nevertheless need to be managed for the receiving environment: The Ahuriri and Waitangi estuaries. A preliminary investigation was carried out that identified high nutrient losses from some tile drains in the Karamū catchment (unpublished data). More research is needed to identify where, when and how nutrients are lost from land in lowland catchments like the Karamū, to be able to identify effective ways of managing nutrient losses to the estuary.

Elevated E.coli concentrations were also a problem in many parts of the Karamū catchment. A study is currently underway to identify the predominant sources of E. coli in the different tributaries to the Karamū/Clive River by using a genetic method called faecal source tracking.


4 Acknowledgements The delivery of this report required contributions from a wide range of HBRC staff. Firstly, members of the ‘Water Quality and Ecology’, ‘Hydrometric’ and ‘Data Management’ Teams in the Environmental Information Section have been essential in collecting and managing the data associated with freshwater State of the Environment monitoring programmes. This has included Vicki Lyon, Daniel Fake, Shane Gilmer, McKay Smiles (nee Dawson), Ariana Mackay, Jane Gardiner, Jordan Ellmers, Andrew Horrell, Jay Bernard, Jeff Cooke, Annabel Beattie and Kim Coulson.

Monthly water quality sampling has to occur in all seasons. Rain, hail or shine. With or without the chills and/or hay fever. The field teams endure particularly long days in the field over summer to collect the extra ecological information required in these busy months. The data management team undergo a painstakingly methodical process to ensure the data being used is of good quality for reporting. All of these staff form the backbone to SOE reporting.

Stu Davey generated maps, and former and current water quality scientists (Dr Adam Uytendaal, Dr Andy Hicks, Dr Sandy Haidekker, Dr Gary Rushworth, and Daniel Fake) collaborated on graphical representations, report style and content, and statistics. We also acknowledge the vital support of other HBRC scientists with special mentions for Anna Madarasz-Smith, Becky Focht, Dr Barry Lynch, Heli Wade and Tim Norris.


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Appendix A Summary statistics by flow in the Ngaruroro and Tūtaekurī catchments All flows

Site Statistic Turb (NTU) SS (mg/l)E.coli (CFU/ 100ml)

Black Disc (m) TP (mg/l) DRP (mg/l) TN (mg/l) DIN (mg/l) DIN / DRP NO3-N

(mg/l)NH4-N (mg/l) DO (mg/l) DO (%) Elec. Cond

(uS/cm) pH Hardness (mg/l) Temp (°C) Chla (mg/

sample) MCI (unit) % EPT Taxa

Min 0.2 0.2 0 0.03 0.002 0.001 0.055 0.007 3 0 0.002 8.5 83 68 7.1 33 4.4 0 116 425%'ile 0.5 0.2 0 0.29 0.002 0.001 0.055 0.009 4 0.001 0.002 8.9 93 76 7.3 33 6.1 0 116 4225%'ile 1.3 0.4 2 0.57 0.002 0.002 0.055 0.014 8 0.006 0.002 10.1 99 89 7.7 39.8 8.3 0.1 116.3 49.8Median 3.1 1.6 4 1.94 0.004 0.002 0.055 0.027 11 0.018 0.002 10.8 100 101 8 49 11.8 0.1 116.5 53.375%'ile 10.2 8.9 20 4.35 0.007 0.004 0.125 0.052 16 0.044 0.005 11.7 104 120 8.2 53 15.9 0.8 120.2 64.695%'ile 18.8 25.5 86 7.79 0.012 0.004 0.325 0.12 29 0.108 0.005 12.8 109 137 8.4 53.8 17.8 1.2 120.9 80.9Max 920 1,270.00 800 10.3 0.87 0.012 3 0.956 266 0.95 0.028 13.4 119 154 9.1 54 20.3 1.7 120.9 80.9Mean 24.5 32.1 36 3.04 0.021 0.003 0.168 0.065 19 0.055 0.004 10.9 101 105 8 46.4 12.3 0.4 117.9 57.5Std_Dev 119.9 165 115 2.86 0.112 0.002 0.403 0.135 35 0.134 0.004 1.2 6 22 0.4 8.2 4.3 0.5 2.3 14.4Count 59 60 59 56 60 60 60 59 59 60 60 54 54 55 58 7 56 28 5 5Min 0.2 0.2 0 0.02 0.002 0.003 0.055 0.011 2 0.005 0.002 8.1 94 71 7.5 NA 3 NA 113 57.15%'ile 0.5 0.2 2 0.06 0.002 0.003 0.055 0.014 3 0.008 0.002 9 95 104 7.5 NA 7 NA 113 57.125%'ile 1 0.3 4 0.62 0.005 0.005 0.055 0.026 4 0.019 0.002 10 98 118 7.7 NA 8.6 NA 115.7 61.5Median 1.6 1 13 3.4 0.009 0.007 0.18 0.095 16 0.089 0.002 10.7 101 132 7.9 NA 12 NA 123.5 74.875%'ile 5.6 7.3 45 5.62 0.014 0.009 0.318 0.187 27 0.18 0.002 11.9 103 146 8.1 NA 16.1 NA 124.6 8495%'ile 27.3 45.4 142 7.54 0.059 0.01 0.59 0.314 42 0.308 0.008 12.4 110 160 8.4 NA 19.3 NA 125 87Max 141 840 4,900 9.9 0.6 0.011 1.49 0.476 52 0.47 0.013 13.6 136 182 8.7 NA 23.4 NA 125 87Mean 9.8 34.1 174 3.5 0.032 0.007 0.257 0.128 18 0.121 0.004 10.8 102 133 7.9 NA 12.6 NA 120.5 73Std_Dev 24.9 136.6 802 2.89 0.097 0.002 0.271 0.126 15 0.125 0.003 1.2 8 21 0.3 NA 4.7 NA 6.5 15Count 34 39 37 27 39 39 39 39 39 39 39 36 37 37 37 NA 37 NA 3 3Min 0.4 0.2 0 0.02 0.002 0.001 0.055 0.027 6 0.019 0.002 8 81 80 7 49 6.4 0 106.7 36.15%'ile 0.9 0.6 1 0.11 0.002 0.002 0.055 0.037 10 0.026 0.002 9.1 89 94 7.3 49 8.1 0 106.7 36.125%'ile 1.9 1.2 6 0.4 0.006 0.004 0.055 0.054 13 0.048 0.002 9.6 97 110 7.6 57.2 10.1 0 107.7 39Median 7.1 6.2 10 0.95 0.009 0.005 0.13 0.086 18 0.076 0.002 10.2 101 120 7.9 61 14.2 0.3 110.6 56.675%'ile 24.9 28 40 3.3 0.017 0.007 0.23 0.152 24 0.136 0.005 11.4 104 140 8.2 62.8 17.6 1.2 118 74.695%'ile 75.8 84 126 4.74 0.059 0.009 0.395 0.199 30 0.187 0.005 11.6 111 155 8.5 65 20.4 3.2 120 78.9Max 910 940 1,600 7.1 0.78 0.026 2.5 0.385 44 0.34 0.04 12.3 119 166 9.1 65 22.8 8 120 78.9Mean 36.4 39.8 79 1.92 0.03 0.006 0.209 0.11 19 0.101 0.004 10.4 101 124 7.9 59.4 14.3 1 112.5 57Std_Dev 120.9 125.9 254 1.9 0.101 0.004 0.331 0.08 8 0.075 0.005 1 7 21 0.4 6.1 4.4 1.9 5.9 19.2Count 59 60 59 57 60 60 60 56 56 60 60 53 53 56 57 5 56 24 5 5Min 0.3 0.2 3 0.12 0.004 0 0.14 0.023 1 0.017 0.002 6.5 69 55 7.4 210 7.7 NA 81.2 4.25%'ile 0.4 0.2 16 0.25 0.006 0.004 0.214 0.029 3 0.022 0.002 7.6 75 382 7.7 210 9 NA 81.2 4.225%'ile 0.7 0.7 34 1.81 0.014 0.012 0.308 0.105 7 0.097 0.002 9.5 93 503 7.9 220 12.3 NA 84.7 8.5Median 1 1.5 69 3.2 0.029 0.024 0.52 0.231 14 0.23 0.002 10.8 100 544 8.1 235 15.1 NA 86.4 13.975%'ile 2 2.4 160 5.07 0.058 0.044 1.118 0.713 19 0.715 0.005 11.8 126 573 8.3 245 18.1 NA 92 28.195%'ile 8.3 6.4 345 6.28 0.08 0.071 1.832 1.204 32 1.398 0.013 13.9 147 589 8.4 250 21 NA 95.7 41Max 56.1 57 7,000 8.3 0.22 0.143 3.4 2.72 476 2.7 0.033 15.3 167 622 8.9 250 23.2 NA 95.7 41Mean 4.6 4.1 293 3.39 0.043 0.033 0.817 0.481 22 0.491 0.006 10.8 108 522 8.1 232.5 15.3 NA 88 18.3Std_Dev 10.9 9.4 977 2.11 0.044 0.03 0.713 0.564 63 0.574 0.006 2 23 86 0.3 17.1 3.9 NA 5.5 15.9Count 52 57 56 47 57 57 57 55 55 57 57 54 54 54 54 4 55 NA 5 4

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All flows






Min 0.4 0.2 3 0.3 0.014 0.011 0.18 0.101 2 0.095 0.002 5.3 12 106 7.3 95 11.9 NA 92.2 3.85%'ile 0.4 0.2 10 0.76 0.015 0.012 0.2 0.119 3 0.113 0.002 7.3 61 175 7.5 95 12.5 NA 92.2 3.825%'ile 0.6 0.2 19 2.94 0.02 0.016 0.25 0.171 8 0.162 0.002 8.8 85 228 7.7 96 13.5 NA 95.2 10.3Median 1.2 0.8 29 4.45 0.03 0.024 0.31 0.219 9 0.21 0.002 9.5 93 254 8 102 15 NA 98.1 35.275%'ile 1.9 1.5 66 6 0.048 0.044 0.492 0.316 12 0.308 0.005 10.8 109 293 8.2 110.2 16.1 NA 100.6 65.195%'ile 4.9 2.2 116 7.08 0.09 0.081 0.83 0.584 14 0.576 0.006 12.1 119 336 8.6 121.8 17 NA 104.7 67.8Max 25.6 11.4 12,000 8.1 0.39 0.29 1.62 0.782 26 0.77 0.085 128 130 400 8.9 124 18.2 NA 104.7 67.8Mean 2.5 1.4 347 4.47 0.048 0.04 0.438 0.29 10 0.278 0.006 11.8 95 260 8 104.3 15 NA 98.1 36.7Std_Dev 4.5 2.2 1,704 2.03 0.062 0.047 0.308 0.181 4 0.173 0.011 16 20 56 0.4 10.6 1.6 NA 4.6 29.1Count 55 59 57 51 57 58 59 58 57 59 59 55 55 57 58 7 58 NA 5 5Min 0.3 0.2 3 0.07 0.057 0.052 0.17 0.007 0 0 0.002 7.3 76 294 7.6 230 7.9 NA 85 0.35%'ile 0.5 0.2 10 0.35 0.074 0.065 0.184 0.007 0 0.001 0.002 8.6 86 335 7.7 230 8.9 NA 85 0.325%'ile 0.8 0.6 44 1.98 0.098 0.09 0.318 0.121 1 0.107 0.002 10.2 98 549 8 240 12.2 NA 86.2 0.9Median 1.2 1.4 90 3.15 0.123 0.117 0.68 0.468 3 0.46 0.005 11.2 116 611 8.3 250 15.3 NA 89.2 2.875%'ile 2.2 1.9 215 5.45 0.158 0.148 1.218 0.811 6 0.792 0.013 12.8 132 640 8.4 260 19.6 NA 91.3 3.195%'ile 7.2 6.9 502 6.61 0.226 0.21 1.798 1.035 8 0.994 0.044 14.4 155 660 8.7 270 22.5 NA 91.7 3.2Max 190 300 21,000 7.8 0.8 0.4 4.4 1.576 9 1.51 0.104 18.9 181 682 8.8 270 26 NA 91.7 3.2Mean 6.5 8.9 876 3.62 0.151 0.129 0.898 0.493 4 0.471 0.013 11.6 117 578 8.2 250 15.8 NA 88.8 2.1Std_Dev 26.8 40.7 3,330 2.04 0.112 0.061 0.768 0.4 3 0.383 0.022 2.2 24 95 0.3 16.3 4.8 NA 3.1 1.6Count 51 57 57 48 57 57 57 57 57 57 57 51 51 54 54 4 54 NA 4 3Min 0.4 0.2 3 0 0.002 0.002 0.055 0.007 2 0 0.002 8.8 10 96 7.3 59 7.4 0 88.2 38.55%'ile 0.8 0.2 7 0.06 0.005 0.003 0.055 0.008 2 0.002 0.002 9 92 106 7.6 59 8.5 0 88.2 38.525%'ile 1.8 1.3 17 0.25 0.008 0.006 0.12 0.053 7 0.04 0.002 9.6 98 138 7.8 62.5 11.4 0.1 94.6 42.8Median 6.7 5 40 0.65 0.014 0.008 0.18 0.106 11 0.097 0.002 10.3 102 150 8.1 67 15 0.5 100 54.475%'ile 29.3 34 100 2.51 0.026 0.013 0.305 0.206 17 0.194 0.005 11.3 108 166 8.3 72.5 19.1 1.3 103 63.995%'ile 57.3 124.5 167 3.93 0.06 0.02 0.575 0.296 23 0.29 0.005 11.8 115 175 8.5 75.6 21.9 2 107.7 71.2Max 290 1690 3,700 6.1 1.83 0.091 5.7 0.622 25 0.56 0.048 12.3 149 197 9.3 76 24.9 4.1 107.7 71.2Mean 26.6 58.8 191 1.47 0.058 0.012 0.33 0.144 12 0.135 0.005 10.4 103 150 8.1 67.4 15.5 0.8 98.8 54Std_Dev 52.8 222.4 612 1.57 0.237 0.014 0.731 0.131 7 0.127 0.006 0.9 16 24 0.4 6.2 4.8 1 7.1 13.1Count 56 60 58 52 60 60 60 60 60 60 60 55 55 57 58 7 57 25 5 5Min 0.8 1.1 5 0.44 0.025 0.021 0.055 0.007 0 0.001 0.002 5.5 13 27 7.4 100 11.2 NA 74.1 0.65%'ile 1 1.5 28 0.47 0.03 0.024 0.082 0.012 0 0.004 0.002 6.2 59 176 7.5 100 11.9 NA 74.1 0.625%'ile 2.2 2.8 51 0.78 0.034 0.028 0.25 0.132 3 0.123 0.004 9.9 97 259 7.8 102.2 13.1 NA 74.8 0.7Median 3.3 4.3 70 1.58 0.04 0.03 0.385 0.243 8 0.23 0.006 10.8 107 279 8.1 104 15.4 NA 77.5 175%'ile 4.7 6.8 130 2.2 0.048 0.037 0.575 0.396 13 0.36 0.017 12.2 119 311 8.4 106.8 17 NA 84.4 9.895%'ile 9.4 11.1 332 3.22 0.066 0.049 1.095 0.788 19 0.74 0.038 13 134 386 8.5 162.2 18.7 NA 88.6 34.3Max 14.1 31 4,000 3.6 0.115 0.07 5.5 4.513 161 4.3 0.118 137.4 157 497 9 176 21.3 NA 88.6 34.3Mean 4.1 5.9 240 1.65 0.045 0.034 0.654 0.463 13 0.437 0.015 13.2 105 289 8.1 114 15.3 NA 79.6 7.6Std_Dev 2.9 5.3 611 0.91 0.017 0.01 0.937 0.781 24 0.749 0.022 17.7 25 78 0.3 27.4 2.4 NA 6.1 14.9Count 52 60 59 34 60 60 60 60 60 60 60 52 52 52 54 7 54 NA 5 5

Tuta

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All flows






Min 0.2 0.2 0 0.12 0.002 0.002 0.055 0.007 1 0 0.002 8.8 89 57 7.1 28 3.6 0 124.4 63.35%'ile 0.3 0.2 1 1.5 0.002 0.002 0.055 0.007 2 0.001 0.002 9.5 93 75 7.3 28 5.2 0 124.4 63.325%'ile 0.5 0.2 6 5.4 0.002 0.004 0.055 0.01 3 0.003 0.002 10.4 96 93 7.7 46 7 0 127.1 68.9Median 0.8 0.2 14 6.9 0.005 0.004 0.055 0.016 4 0.005 0.002 11.2 100 105 8 47 10.2 0 128.7 76.275%'ile 1.4 1.1 30 8.6 0.007 0.005 0.055 0.022 6 0.015 0.005 12 102 120 8.2 49 13.3 0.2 131.6 8395%'ile 2 1.5 57 10.34 0.01 0.006 0.082 0.034 9 0.027 0.005 12.7 107 129 8.4 49.9 15.7 0.6 132 86.3Max 48.9 67 180 14.2 0.053 0.006 0.31 0.075 16 0.069 0.005 15.2 125 139 8.9 50 17.2 1.7 132 86.3Mean 2.2 2.4 24 6.8 0.007 0.004 0.065 0.019 5 0.01 0.003 11.2 100 106 8 44.5 10.4 0.2 128.9 75.7Std_Dev 7.1 9.3 32 2.92 0.009 0.001 0.039 0.012 3 0.012 0.001 1.2 6 18 0.4 8.2 3.6 0.3 3 9.1Count 59 59 58 57 59 59 59 58 58 59 59 56 56 57 55 6 58 42 5 5Min 0.8 1 1 0.01 0.014 0.001 0.24 0.127 10 0.12 0.002 9 91 107 7.6 101 7.2 NA 108.2 235%'ile 1.2 1.5 8 0.31 0.018 0.012 0.335 0.227 11 0.215 0.002 9.7 97 177 7.8 101 7.6 NA 108.2 2325%'ile 2 2.3 20 0.72 0.022 0.018 0.41 0.307 16 0.3 0.002 10.4 100 235 8.1 129.5 9.1 NA 115.5 27.9Median 3.3 4 45 1.5 0.026 0.02 0.595 0.45 23 0.425 0.005 10.9 104 271 8.3 143 12.7 NA 120 37.175%'ile 6.8 10.9 88 2 0.03 0.021 0.775 0.634 31 0.61 0.007 11.9 108 311 8.5 147.2 15.8 NA 123 48.495%'ile 19.4 32.5 1,440 2.6 0.041 0.023 1.005 0.711 39 0.7 0.016 12.6 112 339 8.7 151 17.8 NA 125.3 55.4Max 3,500.00 5,700.00 24,000 4.65 3.8 0.042 7.1 0.907 413 0.9 0.064 13.9 144 348 8.8 151 22.5 NA 125.3 55.4Mean 68.8 112.5 822 1.55 0.1 0.019 0.748 0.468 31 0.453 0.007 11.1 105 270 8.3 136 12.7 NA 118.7 38.1Std_Dev 452.1 736.9 3,344 0.96 0.49 0.005 0.898 0.192 52 0.189 0.01 1 8 54 0.3 20 3.8 NA 6.5 13.7Count 60 60 59 59 60 60 60 58 58 60 60 58 58 57 57 5 59 NA 5 4Min 0.4 0.2 0 0.02 0.002 0.002 0.055 0.007 1 0 0.002 8.6 80 118 7.4 99 8.1 0 100 275%'ile 0.6 0.6 2 0.24 0.008 0.006 0.055 0.008 1 0.001 0.002 9 91 191 7.7 99 8.6 0 100 2725%'ile 0.9 1.1 6 0.8 0.013 0.01 0.12 0.041 4 0.021 0.002 9.6 97 222 8.1 115.5 10.8 0.1 102.1 30.5Median 2.5 1.8 16 2.54 0.018 0.014 0.245 0.182 11 0.174 0.002 10.4 102 260 8.2 126 14.4 1.1 103.8 43.675%'ile 7.7 8.8 68 3.75 0.024 0.018 0.415 0.294 18 0.28 0.005 11.5 109 294 8.5 128.8 19.1 2.1 110.2 55.295%'ile 13.3 21.5 146 4.85 0.031 0.02 0.57 0.39 22 0.355 0.005 11.9 116 314 8.8 134 22.2 6.9 112.7 57.1Max 241 1,130.00 6,200 6.1 0.59 0.036 3.1 0.486 214 0.48 0.077 12.7 159 330 9.1 134 24 14.6 112.7 57.1Mean 10.5 35.6 247 2.49 0.037 0.014 0.344 0.185 14 0.175 0.006 10.5 104 257 8.3 121.4 15.1 2.2 105.8 42.8Std_Dev 34.8 161.5 1,026 1.68 0.098 0.006 0.452 0.144 27 0.143 0.011 1.1 12 45 0.4 13.4 4.8 3.6 5.2 14.6Count 56 60 59 56 60 60 60 59 59 60 60 57 57 59 58 5 59 33 5 4Min 0.7 0.7 2 0 0.016 0 0.11 0.007 0 0 0.002 9 87 132 6.8 146 6.5 0 110 29.15%'ile 0.8 1 6 0.08 0.02 0.013 0.15 0.019 1 0.006 0.002 9.3 92 229 7.5 146 7.6 0 110 29.125%'ile 1.5 1.5 19 1.6 0.028 0.021 0.29 0.131 6 0.118 0.002 10 99 306 8.1 146.8 9.8 0 114.5 40.1Median 2.5 2.6 50 2.15 0.034 0.026 0.47 0.326 11 0.315 0.004 10.6 104 338 8.4 149 13.8 0.2 116 71.375%'ile 4.4 5 122 2.66 0.039 0.032 0.78 0.546 18 0.52 0.012 11.8 111 359 8.6 155.8 18 0.4 119.1 79.895%'ile 8.4 9.8 864 3.2 0.047 0.036 1.01 0.758 26 0.734 0.025 12.5 117 372 8.7 164 20.9 0.6 124.2 81.4Max 3,200.00 4,600.00 12,000 4.3 3.2 0.068 13.1 0.906 1,525 0.89 0.075 14.1 136 373 8.8 164 26.5 1.9 124.2 81.4Mean 65.1 88.8 473 2.05 0.096 0.027 0.787 0.354 38 0.337 0.011 10.9 105 325 8.3 151.8 14.2 0.3 116.7 61Std_Dev 424 604.3 1,823 1.02 0.418 0.01 1.706 0.254 199 0.247 0.016 1.2 9 48 0.4 7.3 4.9 0.5 5.1 23.3Count 57 58 57 57 58 58 58 58 58 58 58 56 56 58 57 5 58 16 5 5Min 0.3 0.2 0 0.02 0.002 0.002 0.055 0.007 0 0 0.002 9.2 85 136 7.7 122 8.4 NA 84.4 9.35%'ile 0.5 0.2 2 0.31 0.009 0.007 0.055 0.007 1 0 0.002 9.3 88 222 7.8 122 9.4 NA 84.4 9.325%'ile 1.1 1.1 9 0.9 0.018 0.015 0.13 0.018 1 0.008 0.002 10 97 270 8.1 131 11.7 NA 84.9 19Median 2.5 3 18 2 0.026 0.02 0.29 0.172 8 0.159 0.002 10.8 105 301 8.4 140 15.9 NA 92.6 2775%'ile 6.8 8 70 3.7 0.032 0.026 0.49 0.347 14 0.335 0.005 11.6 126 326 8.7 143.5 21.1 NA 99.2 43.395%'ile 16.3 26.8 244 5.84 0.042 0.031 0.746 0.51 18 0.47 0.016 13.6 141 335 8.9 151 23.9 NA 100 57.8Max 2,500.00 1,950.00 17,000 8.1 1.62 0.062 4.6 0.609 22 0.6 0.063 15 154 346 9.1 151 28.7 NA 100 57.8Mean 56.9 47.4 458 2.51 0.061 0.021 0.45 0.213 8 0.199 0.007 11 113 294 8.4 137.6 16.6 NA 92.2 31Std_Dev 338.9 259 2,346 1.99 0.216 0.011 0.675 0.192 7 0.189 0.01 1.4 18 43 0.4 10.6 5.3 NA 7.4 18.3Count 55 59 58 56 59 59 59 58 58 59 59 54 54 56 55 5 57 NA 5 5Tu

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< 3 * median flows






Min 0.2 0.2 0 0.33 0.002 0.001 0.055 0.007 3 0 0.002 8.5 83 68 7.1 33 4.4 0 116 425%'ile 0.5 0.2 0 0.37 0.002 0.001 0.055 0.009 4 0.001 0.002 8.8 93 76 7.3 33 6 0 116 4225%'ile 1.2 0.2 2 0.8 0.002 0.002 0.055 0.014 8 0.006 0.002 10 99 91 7.7 39.8 8.4 0.1 116.3 49.8Median 2.9 1.5 4 2.18 0.002 0.002 0.055 0.026 10 0.016 0.002 10.9 100 102 8 49 11.7 0.1 116.5 53.375%'ile 8.4 5.6 14 4.75 0.006 0.003 0.11 0.044 16 0.035 0.005 11.8 104 121 8.2 53 16 0.8 120.2 64.695%'ile 15 15.4 80 7.86 0.009 0.004 0.197 0.101 24 0.093 0.005 12.8 109 138 8.4 53.8 18 1.2 120.9 80.9Max 77.7 105 370 10.3 0.046 0.007 1.07 0.956 266 0.95 0.015 13.4 119 154 9.1 54 20.3 1.7 120.9 80.9Mean 6.4 7.1 23 3.21 0.005 0.003 0.112 0.059 19 0.05 0.004 10.9 101 106 8 46.4 12.3 0.4 117.9 57.5Std_Dev 11.1 17.6 55 2.86 0.007 0.001 0.155 0.137 36 0.136 0.002 1.2 6 22 0.4 8.2 4.3 0.5 2.3 14.4Count 55 56 56 53 56 56 56 55 55 56 56 51 51 52 55 7 53 28 5 5Min NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA5%'ile NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA25%'ile NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NAMedian NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA75%'ile NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA95%'ile NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NAMax NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NAMean NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NAStd_Dev NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NACount NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NAMin NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA5%'ile NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA25%'ile NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NAMedian NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA75%'ile NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA95%'ile NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NAMax NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NAMean NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NAStd_Dev NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NACount NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NAMin 0.3 0.2 3 0.25 0.004 0 0.14 0.023 1 0.017 0.002 6.5 69 55 7.4 210 8.8 NA 81.2 4.25%'ile 0.4 0.2 14 1.02 0.006 0.004 0.206 0.028 2 0.021 0.002 7.3 75 370 7.7 210 10.1 NA 81.2 4.225%'ile 0.6 0.5 26 2.59 0.014 0.01 0.283 0.067 7 0.061 0.002 9.5 94 526 7.9 220 12.8 NA 84.7 8.5Median 0.8 1.1 59 3.7 0.023 0.021 0.42 0.187 12 0.179 0.002 10.8 104 546 8.2 235 16.3 NA 86.4 13.975%'ile 1.2 1.5 110 5.3 0.037 0.034 0.685 0.472 19 0.498 0.005 12.5 126 577 8.4 245 18.4 NA 92 28.195%'ile 2.2 4.1 262 6.64 0.06 0.047 1.392 1.041 31 1.006 0.005 14 148 590 8.4 250 21 NA 95.7 41Max 21.8 26 700 8.3 0.069 0.068 1.86 1.554 476 1.54 0.013 15.3 167 622 8.9 250 23.2 NA 95.7 41Mean 1.6 2.3 99 4 0.028 0.024 0.583 0.333 23 0.327 0.004 10.9 111 531 8.1 232.5 16 NA 88 18.3Std_Dev 3.3 4.7 128 1.93 0.018 0.017 0.427 0.373 69 0.369 0.002 2.1 25 90 0.3 17.1 3.7 NA 5.5 15.9Count 43 47 46 37 47 47 47 46 46 47 47 45 45 45 45 4 46 NA 5 4

Mar

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Haw

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< 3 * median flows






Min NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA5%'ile NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA25%'ile NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NAMedian NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA75%'ile NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA95%'ile NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NAMax NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NAMean NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NAStd_Dev NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NACount NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NAMin NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA5%'ile NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA25%'ile NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NAMedian NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA75%'ile NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA95%'ile NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NAMax NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NAMean NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NAStd_Dev NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NACount NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NAMin 0.4 0.2 3 0 0.002 0.002 0.055 0.007 2 0 0.002 8.8 10 96 7.3 59 7.4 0 88.2 38.55%'ile 0.7 0.2 7 0.12 0.004 0.002 0.055 0.007 2 0.001 0.002 9 94 102 7.6 59 8.8 0 88.2 38.525%'ile 1.7 1.1 16 0.35 0.007 0.006 0.082 0.038 7 0.032 0.002 9.6 99 138 7.8 62.5 11.4 0.1 94.6 42.8Median 4.7 2.8 37 1.12 0.01 0.008 0.16 0.085 10 0.076 0.002 10.4 103 153 8.1 67 16.6 0.5 100 54.475%'ile 15 15.8 82 2.72 0.02 0.011 0.245 0.167 15 0.157 0.005 11.3 110 169 8.3 72.5 20 1.3 103 63.995%'ile 33.2 47 138 4.12 0.032 0.014 0.345 0.221 20 0.214 0.005 11.8 117 176 8.6 75.6 23 2 107.7 71.2Max 120 131 500 6.1 0.062 0.026 0.43 0.296 25 0.29 0.005 12.3 149 197 9.3 76 24.9 4.1 107.7 71.2Mean 14.1 16 63 1.75 0.016 0.009 0.175 0.104 11 0.096 0.003 10.5 104 151 8.1 67.4 16.2 0.9 98.8 54Std_Dev 24.3 31.4 85 1.62 0.014 0.005 0.103 0.082 6 0.081 0.001 1 18 24 0.4 6.2 4.9 1 7.1 13.1Count 46 48 47 41 48 48 48 48 48 48 48 44 44 45 46 7 45 24 5 5Min NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA5%'ile NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA25%'ile NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NAMedian NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA75%'ile NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA95%'ile NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NAMax NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NAMean NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NAStd_Dev NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NACount NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA

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< 3 * median flows Site Statistic Turb (NTU) SS (mg/l)

E.coli (CFU/ 100ml)





Min 0.2 0.2 0 1.4 0.002 0.002 0.055 0.007 1 0 0.002 8.8 89 63 7.1 28 3.6 0 124.4 63.35%'ile 0.3 0.2 1 1.8 0.002 0.002 0.055 0.007 2 0.001 0.002 9.5 93 84 7.3 28 5.2 0 124.4 63.325%'ile 0.5 0.2 6 5.5 0.002 0.004 0.055 0.01 3 0.003 0.002 10.4 96 94 7.7 46 7.3 0 127.1 68.9Median 0.8 0.2 14 7 0.005 0.004 0.055 0.015 4 0.005 0.002 11.1 100 107 8 47 10.2 0 128.7 76.275%'ile 1.3 1 28 8.6 0.007 0.005 0.055 0.021 6 0.011 0.005 12 102 120 8.2 49 13.4 0.2 131.6 8395%'ile 1.7 1.5 46 10.4 0.009 0.006 0.055 0.033 8 0.024 0.005 12.7 107 129 8.4 49.9 15.7 0.6 132 86.3Max 3 11 180 14.2 0.045 0.006 0.13 0.041 14 0.035 0.005 15.2 125 139 8.9 50 17.2 1.7 132 86.3Mean 0.9 0.8 21 7.04 0.006 0.004 0.059 0.017 5 0.009 0.003 11.2 100 107 8 44.5 10.4 0.2 128.9 75.7Std_Dev 0.6 1.5 27 2.68 0.006 0.001 0.015 0.009 3 0.009 0.001 1.2 6 17 0.4 8.2 3.6 0.3 3 9.1Count 57 57 56 55 57 57 57 56 56 57 57 55 55 55 53 6 56 42 5 5Min NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA5%'ile NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA25%'ile NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NAMedian NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA75%'ile NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA95%'ile NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NAMax NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NAMean NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NAStd_Dev NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NACount NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NAMin NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA5%'ile NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA25%'ile NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NAMedian NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA75%'ile NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA95%'ile NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NAMax NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NAMean NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NAStd_Dev NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NACount NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NAMin 0.7 0.7 2 0 0.016 0.01 0.11 0.007 0 0 0.002 9 87 222 6.8 146 6.5 0 110 29.15%'ile 0.8 1 6 0.34 0.02 0.014 0.15 0.019 1 0.006 0.002 9.3 95 278 7.5 146 7.6 0 110 29.125%'ile 1.5 1.5 18 1.7 0.027 0.022 0.28 0.122 6 0.111 0.002 10 99 311 8.1 146.8 9.8 0 114.5 40.1Median 2.2 2.4 47 2.16 0.034 0.026 0.46 0.311 11 0.3 0.002 10.6 105 341 8.4 149 14.2 0.2 116 71.375%'ile 3.7 4.8 118 2.69 0.039 0.032 0.73 0.506 18 0.485 0.008 11.8 112 360 8.6 155.8 18.1 0.4 119.1 79.895%'ile 7 8.7 210 3.2 0.044 0.036 0.977 0.729 25 0.713 0.024 12.6 117 372 8.7 164 20.9 0.6 124.2 81.4Max 245 21 1,400 4.3 0.088 0.051 2 0.906 30 0.89 0.053 14.1 136 373 8.8 164 26.5 1.9 124.2 81.4Mean 7.5 3.9 144 2.12 0.035 0.027 0.531 0.338 12 0.324 0.008 10.9 106 332 8.3 151.8 14.4 0.3 116.7 61Std_Dev 32.7 4 294 0.96 0.012 0.008 0.344 0.244 8 0.241 0.011 1.3 9 34 0.4 7.3 4.9 0.5 5.1 23.3Count 55 56 55 55 56 56 56 56 56 56 56 54 54 56 55 5 56 16 5 5Min NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA5%'ile NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA25%'ile NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NAMedian NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA75%'ile NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA95%'ile NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NAMax NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NAMean NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NAStd_Dev NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NACount NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA

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Min 0.2 0.2 0 1.1 0.002 0.001 0.055 0.007 3 0 0.002 8.5 83 68 7.6 38 7.5 0 116 425%'ile 0.4 0.2 0 2.04 0.002 0.001 0.055 0.007 4 0 0.002 8.7 89 79 7.7 38 7.5 0 116 4225%'ile 0.8 0.2 2 3.65 0.002 0.002 0.055 0.011 5 0.003 0.002 9.5 98 107 7.9 45 12.4 0.1 116.3 49.8Median 1.2 0.2 3 4.5 0.002 0.002 0.055 0.014 8 0.006 0.002 10.1 100 121 8.1 51 15.8 0.1 116.5 53.375%'ile 1.6 1.5 4 7.69 0.002 0.002 0.055 0.019 10 0.011 0.005 10.5 105 134 8.3 53 17.4 0.7 120.2 64.695%'ile 2.8 1.5 15 8.88 0.004 0.003 0.055 0.029 16 0.019 0.005 12.2 109 143 8.4 53.9 19.3 1.2 120.9 80.9Max 3.6 2 120 10.3 0.006 0.004 0.12 0.036 18 0.024 0.005 12.8 119 154 8.5 54 20.3 1.7 120.9 80.9Mean 1.4 0.7 8 5.39 0.002 0.002 0.059 0.016 8 0.008 0.004 10.2 101 119 8.1 48.7 15 0.4 117.9 57.5Std_Dev 0.8 0.6 22 2.43 0.001 0.001 0.016 0.008 4 0.007 0.001 1.1 7 22 0.3 6.2 3.8 0.5 2.3 14.4Count 28 29 29 27 29 29 29 28 28 29 29 26 26 26 28 6 27 23 5 5Min 0.2 0.2 0 2.6 0.002 0.004 0.055 0.011 2 0.005 0.002 8.1 95 122 7.5 NA 6.9 NA 113 57.15%'ile 0.2 0.2 1 2.64 0.002 0.004 0.055 0.012 2 0.006 0.002 8.4 95 124 7.5 NA 7 NA 113 57.125%'ile 0.6 0.2 4 4.8 0.004 0.004 0.055 0.019 3 0.011 0.002 9.5 99 139 7.7 NA 14.2 NA 115.7 61.5Median 1 0.2 10 6.8 0.007 0.005 0.055 0.026 4 0.019 0.002 10 102 149 7.9 NA 16.4 NA 123.5 74.875%'ile 1.3 0.7 26 7.52 0.009 0.007 0.125 0.035 7 0.029 0.002 11.1 104 159 8.3 NA 19.2 NA 124.6 8495%'ile 2 1 37 8.58 0.013 0.008 0.168 0.066 17 0.06 0.008 12.3 110 171 8.4 NA 21.4 NA 125 87Max 2.8 2.1 40 9.9 0.035 0.01 0.4 0.106 19 0.1 0.009 12.4 111 182 8.5 NA 23.4 NA 125 87Mean 1.1 0.5 15 6.16 0.009 0.006 0.104 0.033 6 0.026 0.003 10.3 102 149 8 NA 15.9 NA 120.5 73Std_Dev 0.7 0.5 13 2.11 0.008 0.002 0.087 0.024 5 0.024 0.002 1.2 4 16 0.3 NA 4.6 NA 6.5 15Count 15 17 16 11 17 17 17 17 17 17 17 16 16 16 16 NA 16 NA 3 3Min 0.4 0.2 0 0.71 0.002 0.001 0.055 0.027 6 0.019 0.002 8.9 81 80 7.3 60 9.3 0 106.7 36.15%'ile 0.7 0.2 0 0.85 0.002 0.002 0.055 0.03 9 0.021 0.002 9 89 96 7.5 60 9.4 0 106.7 36.125%'ile 1.2 0.7 5 2.08 0.004 0.002 0.055 0.045 12 0.039 0.002 9.5 100 124 7.9 60.5 15.4 0.1 107.7 39Median 1.8 1.1 7 3.31 0.006 0.004 0.055 0.054 15 0.049 0.002 9.8 102 137 8.1 61.5 17.7 0.3 110.6 56.675%'ile 3.8 2.2 13 4.45 0.007 0.005 0.112 0.065 20 0.063 0.005 10.4 110 153 8.4 63.5 19.9 1.3 118 74.695%'ile 4.9 4.6 36 5.81 0.01 0.007 0.146 0.101 27 0.092 0.005 11.6 115 161 8.8 65 21.4 3.9 120 78.9Max 8.8 14 60 7.1 0.01 0.009 0.27 0.143 44 0.131 0.005 11.7 119 166 9.1 65 22.8 8 120 78.9Mean 2.5 2 13 3.38 0.006 0.004 0.09 0.061 17 0.055 0.004 10.1 104 136 8.2 62 17.2 1.2 112.5 57Std_Dev 1.9 2.7 16 1.72 0.002 0.002 0.053 0.027 8 0.026 0.001 0.9 8 22 0.4 2.2 3.8 2 5.9 19.2Count 28 29 29 28 29 29 29 26 26 29 29 25 25 27 28 4 27 21 5 5Min 0.3 0.2 15 0.9 0.004 0.003 0.14 0.023 2 0.017 0.002 6.5 74 350 7.4 210 8.8 NA 81.2 4.25%'ile 0.3 0.2 18 1.21 0.005 0.004 0.176 0.024 3 0.019 0.002 7.3 75 371 7.6 210 9.5 NA 81.2 4.225%'ile 0.6 0.2 34 2.82 0.012 0.007 0.24 0.056 6 0.048 0.002 9.2 94 501 7.9 217.5 15.4 NA 84.7 8.5Median 0.7 1 69 3.74 0.015 0.012 0.315 0.117 8 0.108 0.002 11.4 124 545 8.1 240 18.1 NA 86.4 13.975%'ile 1.1 1.5 140 5.66 0.022 0.019 0.395 0.187 17 0.178 0.005 13 138 577 8.3 247.5 20.8 NA 92 28.195%'ile 1.7 2.9 335 7.14 0.025 0.024 0.508 0.257 30 0.25 0.005 14.2 158 602 8.4 250 21.6 NA 95.7 41Max 2.8 6 700 8.3 0.036 0.033 0.99 0.802 44 0.79 0.013 15.3 167 622 8.9 250 23.2 NA 95.7 41Mean 0.9 1.3 122 4.23 0.017 0.014 0.351 0.148 13 0.139 0.004 11.3 118 532 8.1 233.3 17.5 NA 88 18.3Std_Dev 0.6 1.3 152 1.99 0.008 0.008 0.166 0.15 11 0.15 0.002 2.3 28 65 0.3 20.8 3.8 NA 5.5 15.9Count 24 28 28 21 28 28 28 28 28 28 28 26 26 26 26 3 27 NA 5 4

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Min 0.4 0.2 3 1.5 0.014 0.011 0.18 0.101 4 0.095 0.002 5.3 12 106 7.3 95 12.4 NA 92.2 3.85%'ile 0.4 0.2 6 1.96 0.015 0.012 0.194 0.113 5 0.106 0.002 7.3 59 141 7.5 95 12.7 NA 92.2 3.825%'ile 0.5 0.2 16 3.91 0.018 0.014 0.232 0.156 8 0.146 0.002 8.7 84 220 7.8 96 14.4 NA 95.2 10.3Median 0.8 0.7 24 5.6 0.021 0.018 0.26 0.192 9 0.181 0.002 9.4 92 234 8 102 15.6 NA 98.1 35.275%'ile 1.4 1.3 40 6.35 0.031 0.026 0.308 0.225 12 0.218 0.005 10.7 107 257 8.2 110.2 16.7 NA 100.6 65.195%'ile 3.6 1.7 87 7.64 0.047 0.038 0.39 0.284 13 0.276 0.005 11.1 116 286 8.6 121.8 17.6 NA 104.7 67.8Max 15.5 4 140 8.1 0.078 0.068 0.5 0.393 16 0.38 0.007 128 125 332 8.9 124 18.2 NA 104.7 67.8Mean 1.6 0.9 36 5.24 0.027 0.023 0.284 0.197 10 0.188 0.004 12.7 93 235 8 104.3 15.5 NA 98.1 36.7Std_Dev 2.7 0.8 33 1.73 0.014 0.012 0.076 0.062 3 0.061 0.001 19.8 21 43 0.4 10.6 1.6 NA 4.6 29.1Count 35 39 38 33 37 38 39 39 38 39 39 36 36 37 38 7 38 NA 5 5Min 0.3 0.2 10 2.3 0.068 0.056 0.17 0.007 0 0 0.002 9.2 99 332 8.1 230 9.3 NA 85 0.35%'ile 0.4 0.2 13 2.34 0.072 0.062 0.17 0.007 0 0 0.002 9.7 100 440 8.1 230 9.4 NA 85 0.325%'ile 0.6 0.5 42 2.9 0.088 0.083 0.212 0.014 0 0.004 0.002 11.1 115 604 8.2 240 16.6 NA 86.2 0.9Median 1 1.1 90 4.75 0.107 0.103 0.27 0.077 1 0.069 0.002 11.6 121 631 8.3 250 19.6 NA 89.2 2.875%'ile 1.2 1.5 108 6.1 0.127 0.12 0.48 0.249 2 0.238 0.005 12.9 152 653 8.6 260 21.5 NA 91.3 3.195%'ile 1.6 1.5 274 6.91 0.138 0.135 0.75 0.542 6 0.532 0.007 14 164 662 8.7 270 24.7 NA 91.7 3.2Max 5.3 1.5 900 7.8 0.21 0.21 1.03 0.808 8 0.79 0.015 15.4 181 676 8.7 270 26 NA 91.7 3.2Mean 1.1 1 135 4.63 0.111 0.105 0.385 0.174 2 0.164 0.004 12 129 612 8.4 250 18.9 NA 88.8 2.1Std_Dev 1 0.5 185 1.83 0.031 0.032 0.255 0.229 2 0.227 0.003 1.5 24 75 0.2 16.3 4.8 NA 3.1 1.6Count 20 23 23 18 23 23 23 23 23 23 23 19 19 21 21 4 21 NA 4 3Min 0.4 0.2 3 0.35 0.002 0.002 0.055 0.007 2 0 0.002 8.8 10 103 7.7 59 11.2 0 88.2 38.55%'ile 0.5 0.2 5 0.87 0.003 0.002 0.055 0.007 2 0.001 0.002 9.1 52 114 7.8 59 12.4 0 88.2 38.525%'ile 1 0.6 12 1.94 0.005 0.004 0.055 0.01 2 0.004 0.002 9.6 106 143 8.1 61 18.2 0.2 94.6 42.8Median 1.6 1.1 20 2.74 0.007 0.005 0.082 0.029 7 0.023 0.002 9.9 110 164 8.3 67.5 19.9 0.8 100 54.475%'ile 2.1 1.5 45 3.9 0.009 0.007 0.15 0.068 10 0.059 0.005 10.9 114 175 8.6 74 22.2 1.4 103 63.995%'ile 3 1.6 134 4.86 0.011 0.008 0.179 0.104 15 0.096 0.005 11.8 131 190 8.8 75.8 24 2.1 107.7 71.2Max 3.8 2 160 6.1 0.026 0.026 0.25 0.191 20 0.179 0.005 12.3 149 197 9.3 76 24.9 4.1 107.7 71.2Mean 1.7 1 43 3.02 0.008 0.006 0.105 0.045 7 0.037 0.003 10.3 108 161 8.3 67.5 19.7 1 98.8 54Std_Dev 0.9 0.5 48 1.41 0.005 0.005 0.058 0.047 5 0.046 0.001 1 26 24 0.4 6.8 3.6 1 7.1 13.1Count 20 22 21 18 22 22 22 22 22 22 22 20 20 20 20 6 21 21 5 5Min 0.8 1.1 5 0.64 0.025 0.021 0.055 0.007 0 0.001 0.002 6.2 13 27 7.5 100 11.2 NA 74.1 0.65%'ile 1 1.5 24 0.72 0.028 0.023 0.055 0.01 0 0.004 0.002 7.4 66 165 7.6 100 12 NA 74.1 0.625%'ile 1.9 2.1 50 1.54 0.032 0.027 0.167 0.08 3 0.071 0.002 10.4 100 249 7.8 102.2 14.2 NA 74.8 0.7Median 2.4 3 62 2.1 0.037 0.029 0.29 0.164 6 0.155 0.005 11.2 111 263 8.2 104 16.3 NA 77.5 175%'ile 3.7 5.3 118 2.32 0.042 0.034 0.387 0.262 9 0.25 0.008 12.4 124 282 8.4 106.8 17.5 NA 84.4 9.895%'ile 5 6.6 260 3.44 0.048 0.04 0.476 0.329 12 0.296 0.013 13.4 136 295 8.5 162.2 18.7 NA 88.6 34.3Max 6.4 9.9 1,100 3.6 0.065 0.051 2.6 2.148 60 2.1 0.037 137.4 157 497 9 176 21.3 NA 88.6 34.3Mean 2.8 3.8 130 2.03 0.038 0.031 0.346 0.219 7 0.205 0.007 14.9 109 258 8.1 114 16 NA 79.6 7.6Std_Dev 1.4 2.1 195 0.86 0.008 0.006 0.394 0.335 10 0.328 0.006 22.1 27 68 0.3 27.4 2.4 NA 6.1 14.9Count 32 39 39 21 39 39 39 39 39 39 39 33 33 33 36 7 35 NA 5 5

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Min 0.2 0.2 0 2.1 0.002 0.002 0.055 0.007 2 0 0.002 8.8 89 63 7.1 28 3.6 0 124.4 63.35%'ile 0.2 0.2 3 3.64 0.002 0.002 0.055 0.007 2 0.001 0.002 9.4 93 83 7.3 28 5.1 0 124.4 63.325%'ile 0.4 0.2 8 6.31 0.002 0.003 0.055 0.009 2 0.003 0.002 10 96 104 7.7 46 8.9 0 127.1 68.9Median 0.6 0.2 16 7.6 0.004 0.004 0.055 0.013 4 0.004 0.002 10.6 100 118 8 47 13.1 0.1 128.7 76.275%'ile 0.9 0.7 31 8.6 0.007 0.004 0.055 0.016 5 0.007 0.005 11.6 102 126 8.2 49 15 0.5 131.6 8395%'ile 1.3 1.5 56 10.56 0.008 0.005 0.1 0.023 9 0.012 0.005 12.4 105 131 8.4 49.9 16.3 0.7 132 86.3Max 1.7 11 180 14.2 0.01 0.006 0.13 0.04 14 0.034 0.005 13.4 125 139 8.9 50 17.2 1.7 132 86.3Mean 0.7 0.8 26 7.7 0.005 0.004 0.062 0.015 4 0.006 0.003 10.8 100 115 8 44.5 11.9 0.3 128.9 75.7Std_Dev 0.4 1.9 33 2.33 0.002 0.001 0.02 0.008 3 0.007 0.001 1.1 6 17 0.4 8.2 3.9 0.4 3 9.1Count 32 32 32 31 32 32 32 32 32 32 32 30 30 30 30 6 31 23 5 5Min 0.8 1 4 0.47 0.014 0.01 0.24 0.127 10 0.12 0.002 9 96 193 8 101 7.2 NA 108.2 235%'ile 0.9 1.4 11 0.61 0.018 0.012 0.332 0.222 11 0.21 0.002 9.7 98 205 8.1 101 7.4 NA 108.2 2325%'ile 1.6 2.1 25 1.4 0.022 0.017 0.38 0.277 16 0.27 0.002 10.1 102 281 8.2 129.5 11.1 NA 115.5 27.9Median 2.2 2.6 44 1.85 0.024 0.019 0.43 0.318 17 0.31 0.005 10.8 106 307 8.4 143 14.7 NA 120 37.175%'ile 3.3 4.1 80 2.45 0.027 0.02 0.6 0.475 23 0.46 0.007 12 110 332 8.6 147.2 17.1 NA 123 48.495%'ile 6.4 10.6 349 2.78 0.031 0.022 0.687 0.575 30 0.555 0.016 12.7 116 343 8.8 151 18.9 NA 125.3 55.4Max 38.3 77 24,000 4.65 0.153 0.039 1.7 0.692 42 0.68 0.018 13.9 144 348 8.8 151 22.5 NA 125.3 55.4Mean 3.9 5.8 855 1.96 0.028 0.019 0.519 0.37 20 0.359 0.006 11 107 299 8.4 136 14.2 NA 118.7 38.1Std_Dev 6.4 13 4,109 0.97 0.023 0.005 0.253 0.138 8 0.134 0.005 1.2 8 43 0.2 20 4 NA 6.5 13.7Count 34 34 34 34 34 34 34 33 33 34 34 32 32 31 32 5 33 NA 5 4Min 0.4 0.2 0 0.77 0.002 0.005 0.055 0.007 1 0 0.002 8.6 94 188 7.5 99 8.4 0 100 275%'ile 0.4 0.3 3 1.61 0.006 0.006 0.055 0.007 1 0.001 0.002 8.9 96 195 7.8 99 8.6 0.1 100 2725%'ile 0.8 0.9 5 2.73 0.011 0.008 0.055 0.014 2 0.004 0.002 9.4 102 264 8.2 115.5 13.8 0.2 102.1 30.5Median 1 1.1 12 3.4 0.014 0.012 0.15 0.07 6 0.05 0.002 10.2 106 292 8.3 126 18.5 1.2 103.8 43.675%'ile 1.9 1.6 24 4.27 0.017 0.014 0.24 0.179 11 0.171 0.005 11.5 113 308 8.7 128.8 21.4 2.2 110.2 55.295%'ile 2.8 2.6 94 5.36 0.02 0.016 0.3 0.259 15 0.252 0.005 12.4 122 318 8.8 134 22.7 8 112.7 57.1Max 8.2 10 480 6.1 0.028 0.019 0.53 0.282 20 0.27 0.077 12.7 159 330 9.1 134 24 14.6 112.7 57.1Mean 1.6 1.6 36 3.54 0.014 0.011 0.163 0.093 7 0.083 0.006 10.5 109 280 8.4 121.4 17.4 2.6 105.8 42.8Std_Dev 1.5 1.7 85 1.26 0.005 0.004 0.112 0.092 6 0.092 0.013 1.3 12 38 0.3 13.4 4.7 3.9 5.2 14.6Count 31 33 33 31 33 33 33 33 33 33 33 30 30 32 32 5 32 26 5 4Min 0.7 0.7 2 0.74 0.016 0.01 0.11 0.007 0 0 0.002 9.3 97 222 6.8 146 6.5 0.2 110 29.15%'ile 0.7 1 4 1.56 0.02 0.012 0.138 0.017 1 0.003 0.002 9.3 97 238 8 146 7.4 0.2 110 29.125%'ile 1.3 1.4 15 2.08 0.024 0.02 0.19 0.065 3 0.054 0.002 10 106 342 8.4 146.8 11.3 0.2 114.5 40.1Median 1.6 1.6 46 2.3 0.03 0.023 0.3 0.137 7 0.127 0.002 10.6 109 358 8.5 149 16.9 0.4 116 71.375%'ile 2.2 2.2 95 3.12 0.039 0.029 0.415 0.287 10 0.275 0.005 12.1 115 368 8.7 155.8 19.5 0.6 119.1 79.895%'ile 3.4 3.6 134 3.78 0.044 0.036 0.55 0.338 14 0.33 0.005 13.2 120 372 8.7 164 21.8 1.6 124.2 81.4Max 5.9 18.3 1,400 4.3 0.088 0.051 2 0.403 18 0.39 0.053 14.1 136 373 8.8 164 26.5 1.9 124.2 81.4Mean 2 2.5 103 2.54 0.033 0.025 0.363 0.172 7 0.161 0.005 11.1 111 342 8.4 151.8 16.1 0.6 116.7 61Std_Dev 1.3 3.3 259 0.8 0.013 0.009 0.342 0.121 5 0.123 0.009 1.4 8 41 0.4 7.3 5.2 0.6 5.1 23.3Count 28 29 28 29 29 29 29 29 29 29 29 27 27 28 28 5 28 7 5 5Min 0.3 0.2 0 0.75 0.002 0.002 0.055 0.007 0 0 0.002 9.3 93 226 8.1 122 9.1 NA 84.4 9.35%'ile 0.5 0.2 2 0.9 0.006 0.006 0.055 0.007 0 0 0.002 9.8 97 246 8.1 122 9.3 NA 84.4 9.325%'ile 0.8 0.7 8 2.15 0.012 0.01 0.1 0.007 1 0 0.002 10.5 115 302 8.4 131 14.4 NA 84.9 19Median 1.1 1.2 15 3.35 0.02 0.015 0.145 0.019 1 0.011 0.002 11.4 124 324 8.7 140 20.3 NA 92.6 2775%'ile 1.8 2.5 50 4.4 0.024 0.02 0.265 0.132 7 0.125 0.005 12.6 139 332 8.9 143.5 23.3 NA 99.2 43.395%'ile 5.5 6.8 148 6.5 0.03 0.027 0.389 0.242 12 0.232 0.005 13.7 144 336 9 151 24.5 NA 100 57.8Max 11.3 29 600 8.1 0.058 0.033 1.84 0.381 15 0.36 0.019 15 154 346 9.1 151 28.7 NA 100 57.8Mean 2.1 3.5 53 3.58 0.02 0.016 0.228 0.075 4 0.066 0.004 11.7 125 312 8.6 137.6 19.2 NA 92.2 31Std_Dev 2.7 6.9 111 1.87 0.01 0.007 0.313 0.101 4 0.098 0.003 1.5 15 30 0.3 10.6 5.2 NA 7.4 18.3Count 29 32 32 30 32 32 32 32 32 32 32 29 29 31 30 5 31 NA 5 5

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LQ flows






Min 0.2 0.2 0 3.16 0.002 0.001 0.055 0.007 4 0 0.002 8.5 90 90 7.7 38 7.7 0.1 116 425%'ile 0.3 0.2 0 3.36 0.002 0.001 0.055 0.007 4 0 0.002 8.6 92 95 7.8 38 8.6 0.1 116 4225%'ile 0.7 0.2 1 4.5 0.002 0.002 0.055 0.01 5 0.003 0.002 9.3 98 121 8 45 15 0.1 116.2 47.2Median 0.9 0.2 2 6.18 0.002 0.002 0.055 0.014 8 0.004 0.002 9.7 100 133 8.2 51 16.7 0.2 118.2 52.875%'ile 1.5 0.8 3 8.1 0.002 0.002 0.055 0.016 9 0.008 0.005 10.4 104 138 8.3 53 18.7 0.8 120.5 56.295%'ile 2.7 1.5 5 9.49 0.004 0.003 0.088 0.026 13 0.016 0.005 11.7 107 145 8.4 53.9 19.8 1.3 120.9 59.2Max 3.6 1.5 15 10.3 0.006 0.004 0.12 0.036 18 0.024 0.005 12.2 109 154 8.5 54 20.3 1.7 120.9 59.2Mean 1.2 0.5 3 6.51 0.003 0.002 0.061 0.015 8 0.006 0.004 9.9 101 129 8.2 48.7 16.1 0.5 118.3 51.7Std_Dev 0.9 0.5 3 2.15 0.001 0.001 0.019 0.007 4 0.006 0.001 1 5 15 0.2 6.2 3.4 0.5 2.5 7.1Count 18 19 19 18 19 19 19 19 19 19 19 17 17 16 18 6 17 17 4 4Min 0.2 0.2 0 3.4 0.002 0.004 0.055 0.014 2 0.008 0.002 8.1 95 141 7.5 NA 7.1 NA 123.5 74.85%'ile 0.2 0.2 1 3.4 0.002 0.004 0.055 0.015 2 0.009 0.002 8.1 95 141 7.5 NA 7.1 NA 123.5 74.825%'ile 0.6 0.2 5 5.1 0.005 0.005 0.055 0.02 3 0.013 0.002 9 97 147 7.7 NA 14.3 NA 123.5 74.8Median 1 0.2 11 6.3 0.008 0.007 0.055 0.025 3 0.018 0.002 9.8 101 154 8 NA 18.4 NA 124.2 80.975%'ile 1.5 0.7 26 7.3 0.01 0.008 0.134 0.031 5 0.021 0.006 10.3 103 169 8.4 NA 20.2 NA 125 8795%'ile 2.5 1.3 36 7.57 0.012 0.009 0.262 0.063 12 0.057 0.008 11.5 104 176 8.5 NA 22.4 NA 125 87Max 2.8 2.1 37 7.6 0.014 0.01 0.4 0.106 19 0.1 0.009 12.4 105 182 8.5 NA 23.4 NA 125 87Mean 1.1 0.5 16 6 0.008 0.007 0.106 0.031 5 0.025 0.004 9.9 100 157 8 NA 17.3 NA 124.2 80.9Std_Dev 0.8 0.6 13 1.58 0.003 0.002 0.107 0.025 5 0.026 0.003 1.2 4 13 0.4 NA 4.7 NA 1.1 8.6Count 9 11 11 6 11 11 11 11 11 11 11 10 10 10 10 NA 10 NA 2 2Min 0.4 0.2 0 2.35 0.002 0.001 0.055 0.027 9 0.019 0.002 8.9 95 99 7.3 60 10.1 0 108 36.15%'ile 0.5 0.2 0 2.61 0.002 0.002 0.055 0.029 10 0.02 0.002 8.9 96 104 7.4 60 11.9 0 108 36.125%'ile 1 0.6 6 3.3 0.002 0.002 0.055 0.039 12 0.031 0.002 9.5 101 134 7.8 60.5 17.5 0.1 109.3 38Median 1.3 0.8 8 4.05 0.006 0.004 0.055 0.054 16 0.046 0.002 9.6 102 148 8.3 61.5 18.9 0.3 113.9 48.375%'ile 1.7 1.1 11 5.4 0.006 0.005 0.11 0.059 20 0.053 0.005 10.1 113 160 8.7 63.5 20.9 1.6 118.7 67.895%'ile 3.6 1.5 19 5.97 0.008 0.007 0.186 0.105 23 0.099 0.005 11.2 117 164 9 65 22.1 4.9 120 78.9Max 4.9 2.7 28 7.1 0.01 0.009 0.27 0.143 27 0.131 0.005 11.6 119 166 9.1 65 22.8 8 120 78.9Mean 1.6 0.9 9 4.27 0.005 0.004 0.092 0.06 16 0.051 0.003 9.9 106 145 8.3 62 18.8 1.4 114 52.9Std_Dev 1.1 0.6 7 1.26 0.002 0.002 0.061 0.029 5 0.029 0.001 0.8 7 18 0.5 2.2 3.1 2.2 5.6 19.5Count 17 18 18 18 18 18 18 18 18 18 18 15 15 16 17 4 16 17 4 4Min 0.4 0.2 21 2.9 0.005 0.003 0.14 0.023 2 0.017 0.002 6.5 74 457 7.7 250 12 NA 81.2 4.25%'ile 0.4 0.2 21 2.9 0.005 0.003 0.144 0.023 2 0.017 0.002 6.5 75 458 7.7 250 12 NA 81.2 4.225%'ile 0.6 0.2 48 3.61 0.01 0.007 0.215 0.034 5 0.025 0.002 8.2 79 530 7.9 250 16.8 NA 83.8 8.5Median 0.7 0.5 90 5.65 0.014 0.011 0.26 0.073 8 0.062 0.002 10.8 126 564 7.9 250 18.4 NA 88.6 13.975%'ile 1.1 1.1 325 6.98 0.02 0.016 0.34 0.158 8 0.152 0.004 11.7 127 587 8.2 250 21.4 NA 93.2 28.195%'ile 1.2 1.7 504 8.1 0.028 0.026 0.424 0.23 29 0.222 0.011 13.4 142 605 8.3 250 22.5 NA 95.7 41Max 1.4 2.4 700 8.3 0.036 0.033 0.48 0.256 44 0.25 0.013 13.9 148 607 8.4 250 23.2 NA 95.7 41Mean 0.8 0.8 190 5.45 0.016 0.013 0.279 0.103 11 0.095 0.004 10.2 108 551 8 250 18.3 NA 88.5 18.3Std_Dev 0.3 0.7 211 1.99 0.009 0.009 0.097 0.08 12 0.081 0.004 2.4 28 50 0.2 NA 3.7 NA 6.2 15.9Count 10 12 12 9 12 12 12 12 12 12 12 11 11 11 11 1 11 NA 4 4

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LQ flows






Min 0.4 0.2 3 1.5 0.014 0.011 0.18 0.112 7 0.106 0.002 5.3 54 126 7.5 95 12.9 NA 92.2 3.85%'ile 0.4 0.2 8 2.34 0.015 0.012 0.187 0.122 7 0.116 0.002 6.7 67 153 7.5 95 13.2 NA 92.2 3.825%'ile 0.5 0.2 19 4.34 0.016 0.014 0.225 0.146 9 0.14 0.002 8.5 83 220 7.8 98 15 NA 95.2 10.3Median 0.7 0.7 26 5.8 0.02 0.016 0.25 0.18 10 0.168 0.002 9.1 92 232 8 102 15.7 NA 98.1 35.275%'ile 1.4 1.2 39 6.5 0.024 0.02 0.29 0.206 13 0.2 0.005 10 103 242 8.1 107.5 16.8 NA 100.6 65.195%'ile 3.1 2 82 7.62 0.026 0.023 0.306 0.222 14 0.211 0.005 10.8 113 254 8.3 124 17.7 NA 104.7 67.8Max 15.5 4 140 8.1 0.032 0.031 0.36 0.232 15 0.22 0.007 11.1 117 262 8.7 124 18.1 NA 104.7 67.8Mean 1.7 0.9 37 5.49 0.02 0.017 0.258 0.177 11 0.169 0.004 9.2 93 225 8 104.4 15.8 NA 98.1 36.7Std_Dev 3.3 0.9 31 1.65 0.005 0.005 0.045 0.036 2 0.035 0.001 1.3 15 30 0.3 11.3 1.4 NA 4.6 29.1Count 21 24 23 18 23 24 24 24 24 24 24 21 21 22 23 5 23 NA 5 5Min 0.3 0.2 18 2.3 0.068 0.056 0.17 0.007 0 0 0.002 9.2 100 528 8.2 230 12.2 NA 85 0.35%'ile 0.3 0.2 21 2.31 0.07 0.058 0.17 0.007 0 0 0.002 9.3 100 539 8.2 230 12.7 NA 85 0.325%'ile 0.6 0.5 42 2.58 0.084 0.077 0.19 0.012 0 0.001 0.002 10.8 116 616 8.3 240 18.4 NA 85.6 0.3Median 1 0.9 80 3.85 0.111 0.105 0.24 0.016 0 0.009 0.002 11.9 127 648 8.3 250 20 NA 87.5 1.775%'ile 1.2 1.5 100 5.45 0.127 0.12 0.372 0.138 1 0.124 0.005 13 155 660 8.4 260 23.6 NA 90.1 3.295%'ile 2.3 1.5 240 6.79 0.144 0.131 0.6 0.28 2 0.26 0.013 14.3 164 665 8.7 270 25.3 NA 91 3.2Max 5.3 1.5 270 7 0.21 0.21 1.03 0.808 7 0.79 0.015 15.4 181 676 8.7 270 26 NA 91 3.2Mean 1.2 0.9 93 4.17 0.113 0.105 0.331 0.122 1 0.111 0.005 12 133 632 8.4 250 20.2 NA 87.8 1.7Std_Dev 1.3 0.5 72 1.72 0.036 0.037 0.23 0.21 2 0.207 0.004 1.7 25 38 0.2 16.3 3.9 NA 3 2.1Count 13 15 15 12 15 15 15 15 15 15 15 12 12 13 13 4 13 NA 3 2Min 0.4 0.2 7 2.1 0.004 0.002 0.055 0.007 2 0 0.002 9.4 10 134 7.7 67 17.1 0 88.2 38.55%'ile 0.4 0.2 7 2.1 0.004 0.002 0.055 0.007 2 0 0.002 9.4 10 134 7.7 67 17.1 0 88.2 38.525%'ile 0.7 0.2 12 3 0.005 0.003 0.055 0.009 2 0.002 0.002 9.7 106 158 7.9 67.5 18.7 0.5 94.1 41.3Median 0.9 0.7 16 4 0.006 0.004 0.055 0.014 3 0.004 0.004 10 111 168 8.5 71 20.3 0.8 100.7 49.375%'ile 1.5 1.3 37 4.9 0.008 0.006 0.15 0.022 7 0.01 0.005 10.8 122 180 8.8 75 23.9 1.3 104.6 5895%'ile 2.2 1.5 70 5.9 0.01 0.008 0.185 0.064 9 0.052 0.005 12 144 196 9.2 76 24.7 1.8 107.7 61.5Max 2.4 1.5 100 6.1 0.01 0.009 0.2 0.071 10 0.059 0.005 12.3 149 197 9.3 76 24.9 2 107.7 61.5Mean 1.1 0.8 28 4.03 0.006 0.005 0.097 0.022 5 0.013 0.004 10.3 105 168 8.4 71.2 21.2 0.9 99.3 49.7Std_Dev 0.7 0.5 28 1.35 0.002 0.002 0.058 0.022 3 0.021 0.001 1 41 20 0.6 4.4 2.9 0.6 8.1 10.3Count 8 10 10 7 10 10 10 10 10 10 10 8 8 9 8 4 9 10 4 4Min 0.8 1.5 5 0.64 0.025 0.023 0.055 0.007 0 0.001 0.002 6.2 65 163 7.5 102 12.5 NA 74.1 0.65%'ile 0.9 1.5 22 0.68 0.028 0.024 0.055 0.009 0 0.003 0.002 7.6 79 169 7.7 102 12.5 NA 74.1 0.625%'ile 1.4 2 59 1.52 0.033 0.027 0.158 0.062 2 0.049 0.002 10.4 103 249 7.9 102.8 15.5 NA 74.8 0.7Median 2.2 2.8 70 2.1 0.036 0.029 0.26 0.121 3 0.106 0.005 10.9 111 259 8.2 104 16.8 NA 77.5 175%'ile 4 5 110 2.96 0.046 0.036 0.35 0.214 8 0.202 0.006 12.3 125 268 8.4 124.2 18 NA 84.4 9.895%'ile 5 6.5 260 3.5 0.052 0.04 0.55 0.301 11 0.29 0.012 12.7 134 305 8.5 176 18.9 NA 88.6 34.3Max 5.2 9.9 380 3.6 0.065 0.051 2.6 2.148 60 2.1 0.019 13.4 153 497 9 176 21.3 NA 88.6 34.3Mean 2.6 3.6 99 2.11 0.039 0.031 0.349 0.213 7 0.201 0.006 10.9 113 262 8.2 118.4 16.6 NA 79.6 7.6Std_Dev 1.5 2.3 84 0.98 0.01 0.007 0.489 0.415 12 0.408 0.004 1.7 19 69 0.3 32.3 2.2 NA 6.1 14.9Count 20 25 25 15 25 25 25 25 25 25 25 20 20 19 22 5 22 NA 5 5

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LQ flows






Min 0.2 0.2 0 5.4 0.002 0.002 0.055 0.008 2 0.002 0.002 8.8 89 89 7.6 46 3.6 0 124.4 63.35%'ile 0.2 0.2 1 6.1 0.002 0.002 0.055 0.008 2 0.002 0.002 9.1 91 91 7.6 46 4.3 0 124.4 63.325%'ile 0.4 0.2 9 7.83 0.002 0.003 0.055 0.009 2 0.003 0.002 9.8 97 117 8 46 12.2 0 127.1 68.9Median 0.6 0.2 20 8.6 0.004 0.004 0.055 0.012 4 0.003 0.002 10.5 101 125 8.1 48 13.6 0.1 128.7 76.275%'ile 0.9 0.6 35 9.72 0.005 0.004 0.055 0.016 4 0.005 0.005 11.4 103 129 8.2 49.2 15.6 0.5 131.6 8395%'ile 1.2 1.3 64 11.2 0.008 0.005 0.055 0.018 8 0.007 0.005 12.2 108 137 8.6 50 16.2 0.8 132 86.3Max 1.4 1.5 70 14.2 0.009 0.006 0.055 0.02 10 0.008 0.005 13.4 125 139 8.9 50 16.4 1.7 132 86.3Mean 0.7 0.5 26 8.86 0.004 0.004 0.055 0.013 4 0.004 0.004 10.6 101 122 8.2 47.8 12.8 0.3 128.9 75.7Std_Dev 0.3 0.4 22 1.93 0.002 0.001 0 0.004 2 0.002 0.001 1.2 7 14 0.3 1.8 3.7 0.5 3 9.1Count 18 18 18 17 18 18 18 18 18 18 18 18 18 17 17 5 18 14 5 5Min 0.8 1 4 1.2 0.018 0.012 0.24 0.127 10 0.12 0.002 9 98 204 8 139 7.3 NA 108.2 235%'ile 0.8 1.2 6 1.22 0.018 0.012 0.276 0.166 10 0.156 0.002 9.3 99 209 8.1 139 8 NA 108.2 2325%'ile 1.4 1.5 20 1.94 0.02 0.016 0.36 0.272 16 0.26 0.002 10 102 306 8.4 141 13.3 NA 115.5 27.9Median 1.7 2.2 37 2.19 0.022 0.018 0.4 0.297 17 0.29 0.005 10.8 107 331 8.5 144.5 15.8 NA 120 37.175%'ile 2.2 2.7 80 2.6 0.026 0.02 0.43 0.322 19 0.31 0.011 11.9 110 342 8.6 148.5 18 NA 123 48.495%'ile 2.6 3.5 80 4.24 0.027 0.02 0.554 0.44 23 0.422 0.015 12.9 116 345 8.8 151 19.1 NA 125.3 55.4Max 3 4.6 210 4.65 0.029 0.023 0.65 0.473 30 0.46 0.017 13.9 144 348 8.8 151 19.9 NA 125.3 55.4Mean 1.8 2.3 51 2.42 0.023 0.017 0.409 0.306 18 0.294 0.006 11 109 312 8.5 144.8 14.9 NA 118.7 38.1Std_Dev 0.6 0.9 47 1 0.003 0.003 0.093 0.081 5 0.079 0.005 1.3 10 44 0.2 5.1 3.7 NA 6.5 13.7Count 18 18 18 18 18 18 18 18 18 18 18 18 18 17 17 4 18 NA 5 4Min 0.4 0.2 3 2.4 0.006 0.005 0.055 0.007 1 0 0.002 8.6 96 188 8.1 121 8.4 0.1 100 275%'ile 0.4 0.2 4 2.42 0.007 0.006 0.055 0.007 1 0.001 0.002 8.7 96 197 8.1 121 9.5 0.1 100 2725%'ile 0.7 0.8 8 2.9 0.009 0.007 0.055 0.009 1 0.002 0.002 9.3 105 282 8.3 123.5 17.8 0.2 102.1 30.5Median 0.9 1 12 3.9 0.012 0.01 0.055 0.014 2 0.004 0.002 10 110 299 8.6 126.5 19.2 1.1 103.8 43.675%'ile 1.4 1.4 16 4.98 0.014 0.012 0.12 0.07 7 0.025 0.005 11.5 116 316 8.8 130.5 22.3 2 110.2 55.295%'ile 2.4 1.5 35 5.84 0.017 0.014 0.198 0.165 10 0.153 0.005 12.5 126 323 8.9 134 22.9 3.9 112.7 57.1Max 2.6 1.8 90 6.1 0.021 0.018 0.25 0.194 13 0.182 0.077 12.7 159 330 9.1 134 24 14.6 112.7 57.1Mean 1.1 1 18 3.98 0.012 0.01 0.096 0.046 4 0.034 0.008 10.5 112 290 8.6 127 18.6 2.1 105.8 42.8Std_Dev 0.6 0.4 20 1.21 0.004 0.003 0.062 0.061 4 0.059 0.017 1.4 14 39 0.3 5.4 4.3 3.5 5.2 14.6Count 16 18 18 17 18 18 18 18 18 18 18 18 18 18 18 4 18 16 5 4Min 0.7 0.7 4 1.8 0.023 0.012 0.11 0.007 0 0 0.002 9.3 99 287 8.1 146 6.5 0.2 110 43.85%'ile 0.7 0.8 5 1.84 0.023 0.013 0.118 0.01 1 0.001 0.002 9.3 100 290 8.1 146 6.8 0.2 110 43.825%'ile 1.2 1.1 11 2.1 0.024 0.021 0.162 0.06 3 0.046 0.002 10.2 107 352 8.3 147.8 9.6 0.3 110 43.8Median 1.5 1.5 35 2.45 0.028 0.023 0.29 0.193 7 0.179 0.002 11.5 110 363 8.5 153 16.8 0.5 113 57.675%'ile 2.1 1.7 49 3.18 0.039 0.029 0.348 0.257 10 0.25 0.005 12.5 115 371 8.7 161.2 18.2 1.5 116 71.395%'ile 2.5 2.8 90 3.97 0.043 0.033 0.41 0.338 11 0.33 0.005 13.7 120 372 8.7 164 21.8 1.9 116 71.3Max 2.9 3 120 4.3 0.045 0.04 0.43 0.338 12 0.33 0.053 14.1 136 373 8.8 164 22.4 1.9 116 71.3Mean 1.6 1.6 39 2.7 0.032 0.025 0.27 0.167 6 0.154 0.007 11.5 112 355 8.5 154.3 14.8 0.8 113 57.6Std_Dev 0.6 0.6 34 0.76 0.008 0.007 0.104 0.117 4 0.12 0.013 1.5 9 26 0.2 9.1 5.4 0.9 4.2 19.5Count 14 15 15 15 15 15 15 15 15 15 15 15 15 15 15 3 15 3 2 2Min 0.3 0.2 0 0.9 0.002 0.002 0.055 0.007 0 0 0.002 9.3 103 226 8.2 134 9.2 NA 84.4 9.35%'ile 0.3 0.2 1 1.26 0.003 0.004 0.055 0.007 1 0 0.002 9.5 103 253 8.3 134 10.3 NA 84.4 9.325%'ile 0.6 0.2 8 2.9 0.01 0.007 0.055 0.007 1 0 0.002 10.6 121 320 8.5 137 17.6 NA 84.9 19Median 0.8 0.7 15 3.98 0.014 0.011 0.12 0.008 1 0.002 0.002 11.6 127 326 8.8 140.5 20.3 NA 92.6 2775%'ile 1.3 1.5 28 6.05 0.024 0.016 0.132 0.02 2 0.008 0.005 13.5 139 332 8.9 146 23.6 NA 99.2 43.395%'ile 1.7 4.4 58 6.89 0.027 0.025 0.206 0.124 6 0.114 0.005 13.7 148 335 9 151 24.7 NA 100 57.8Max 6.8 28 200 8.1 0.032 0.028 0.27 0.175 7 0.163 0.005 14.8 154 338 9.1 151 25.1 NA 100 57.8Mean 1.3 2.7 30 4.3 0.016 0.013 0.119 0.029 2 0.021 0.004 11.8 129 320 8.7 141.5 19.8 NA 92.2 31Std_Dev 1.5 6.6 47 2 0.008 0.007 0.06 0.051 2 0.049 0.001 1.6 14 26 0.3 7 4.6 NA 7.4 18.3Count 16 17 17 16 17 17 17 17 17 17 17 17 17 17 17 4 17 NA 5 5

Man

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Appendix B Summary statistics by flow in the Karamū and Ahuriri catchments All flows




(uS/cm) pH Hardness (mg/l) Temp (°C) MCI (unit) % EPT

Taxa

Min 0.8 1 5 0.08 0.086 0.06 0.39 0.007 0 0 0.002 0.2 2 476 7.4 220 5.5 66.3 05%'ile 0.9 1.1 63 0.15 0.094 0.069 0.588 0.057 0 0.003 0.002 1.5 16 496 7.5 220 7.6 66.3 025%'ile 1.7 2 120 0.95 0.146 0.116 1.23 0.436 2 0.36 0.006 7 68 656 7.7 270 10.4 67.7 0Median 2.4 3.5 245 1.08 0.191 0.16 1.955 0.994 9 0.935 0.038 8.7 82 764 7.8 290 14.4 71.2 075%'ile 4.5 7.6 700 1.7 0.26 0.22 3 1.816 14 1.74 0.063 10.2 98 845 7.9 300 18.5 73.7 2.395%'ile 6.5 9.6 1,480 2.22 0.489 0.387 4.24 2.654 17 2.57 0.178 11.4 122 917 8.1 354 21.6 75.5 8.3Max 98.1 188 25,000 2.8 0.81 0.47 8.6 4.98 26 4.9 0.41 15.4 174 983 8.6 360 24.3 75.8 8.3Mean 6.8 9.9 1,173 1.29 0.243 0.192 2.274 1.256 9 1.165 0.065 8.4 82 749 7.8 288.3 14.5 70.9 1.7Std_Dev 16.5 27.4 3,816 0.64 0.152 0.109 1.498 1.063 7 1.056 0.094 2.9 30 129 0.3 45.8 4.9 3.5 3.7Count 48 58 56 43 58 58 58 58 58 58 58 52 52 55 55 6 54 9 5Min 0.7 0.7 22 0.06 0.06 0.04 0.15 0.007 0 0 0.002 3.2 35 177 6 75 8.8 68.3 1.85%'ile 1.5 0.8 45 0.16 0.076 0.058 0.185 0.008 0 0.001 0.002 4.8 53 219 7.4 75 10.1 68.3 1.825%'ile 2.2 1.5 120 0.59 0.097 0.068 0.455 0.155 1 0.128 0.005 7.2 73 295 7.6 92.2 12.6 68.6 4Median 3 3.1 230 0.83 0.116 0.09 0.79 0.445 7 0.39 0.026 9 88 372 7.8 100 16.2 69.5 4.975%'ile 5.6 6.5 410 1.42 0.148 0.116 1.515 1.001 12 0.975 0.065 10 103 477 8.2 109.5 18.6 74.9 9.495%'ile 9.8 11.4 3,750 2.22 0.211 0.146 2.35 1.728 16 1.595 0.117 11.6 120 560 8.5 135 20.8 78.8 12.6Max 132 154 24,000 2.9 0.54 0.23 7.4 5.89 48 5.6 0.25 13.8 142 693 9.1 135 24.3 78.8 12.6Mean 7.6 7.7 1,442 1.12 0.136 0.1 1.194 0.746 8 0.679 0.046 8.8 88 390 7.9 101.8 15.8 71.8 6.5Std_Dev 18.5 20.5 4,156 0.76 0.075 0.042 1.235 0.946 8 0.897 0.054 2.2 23 122 0.5 21.4 3.9 4.4 4.1Count 55 60 58 29 60 60 60 60 60 60 60 56 56 57 56 5 56 5 5Min 0.4 0.2 50 0.1 0.028 0.017 0.19 0.007 0 0 0.002 0.3 3 163 7.5 84 6.7 65.3 05%'ile 0.7 0.2 80 0.45 0.032 0.026 0.22 0.014 0 0.002 0.002 6.6 68 297 7.6 84 8 65.3 025%'ile 1 0.8 280 1.67 0.056 0.044 0.305 0.045 1 0.033 0.002 9.2 90 516 8 225 10.8 66.7 0.1Median 1.7 1.2 600 2.3 0.076 0.064 0.49 0.13 2 0.105 0.006 10.6 102 617 8.2 240 14.8 69.7 0.175%'ile 2.6 1.8 1,600 2.91 0.094 0.089 0.78 0.486 7 0.465 0.017 11.9 114 650 8.4 267.5 18 73.3 7.895%'ile 5.8 2.8 5,070 3.48 0.118 0.104 1.315 0.803 10 0.765 0.034 13.9 147 684 8.6 286 21.4 75.2 15.4Max 306.7 250 120,000 4.1 0.52 0.26 7.2 4.454 20 4.3 0.117 16.1 175 760 9.1 290 25.7 75.4 15.4Mean 11 7.7 3,854 2.24 0.089 0.07 0.782 0.357 4 0.337 0.014 10.5 105 576 8.2 229.1 14.7 70 3.9Std_Dev 47 35.2 16,142 0.96 0.08 0.04 1.054 0.654 4 0.635 0.019 2.6 29 121 0.3 68 4.9 4.2 7.7Count 56 59 56 41 60 60 60 60 60 60 60 57 57 58 57 7 57 6 4Min 0.6 0.2 40 0.09 0.071 0.047 0.4 0.009 0 0 0.002 0.2 2 371 6.3 188 5.6 67.1 05%'ile 0.8 0.8 64 0.2 0.078 0.064 0.445 0.036 0 0.002 0.002 1.1 9 428 7.1 188 8.2 67.1 025%'ile 1.3 1.9 165 1.05 0.118 0.093 1.06 0.38 3 0.202 0.007 5 52 600 7.6 220 11.2 67.6 0Median 2.4 3.4 280 1.6 0.14 0.122 1.85 1.119 11 1.015 0.038 8.5 80 699 7.8 260 14.8 69.3 2.175%'ile 4.7 5.9 450 2.3 0.21 0.162 2.9 2.201 21 2.1 0.077 10.1 103 780 8.1 332.5 18.4 71.8 7.795%'ile 6.7 10.1 1,320 2.95 0.41 0.275 5 3.587 27 3.5 0.215 12.6 126 860 8.4 372 22.2 78.8 11.1Max 706 165 38,000 4.2 0.83 0.38 8.5 7.109 68 6.9 0.87 16.6 169 945 8.7 380 25.9 78.8 11.1Mean 20.4 9.6 1,479 1.71 0.201 0.146 2.349 1.586 13 1.476 0.081 7.9 77 693 7.8 276.9 15 70.5 3.8Std_Dev 100.2 27.3 5,822 0.88 0.157 0.085 1.82 1.59 13 1.579 0.141 4 41 135 0.4 69.6 4.8 4.8 5.2Count 51 60 59 45 60 60 60 60 60 60 60 56 56 55 56 7 56 5 4

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All flows




(uS/cm) pH Hardness (mg/l) Temp (°C) MCI (unit) % EPT

Taxa

Min 0.4 0.2 9 0.34 0.04 0.021 0.22 0.007 0 0 0.002 0.1 1 461 7 260 4.6 63.8 0.15%'ile 0.5 0.2 15 0.5 0.058 0.04 0.31 0.007 0 0 0.002 0.3 3 515 7.3 260 7.2 63.8 0.125%'ile 0.9 0.9 42 1.38 0.096 0.073 0.69 0.028 0 0.005 0.002 2.9 32 628 7.5 262.5 9.7 64.7 0.2Median 1.4 1.4 130 2.02 0.177 0.154 1.415 0.088 1 0.066 0.005 5.6 52 719 7.6 270 14.1 71.4 2.175%'ile 2.2 2.1 258 2.5 0.275 0.25 1.735 0.26 3 0.245 0.014 7.2 66 792 7.7 287.5 17.9 77.2 5.195%'ile 4.7 3.7 396 3.51 0.39 0.365 2.15 0.602 9 0.585 0.026 9.1 82 845 7.9 298 20.2 78 6.3Max 25.8 30 3,100 4.4 0.6 0.59 5.4 3.58 28 3.5 0.135 11 114 988 8.1 300 24.2 78 6.3Mean 2.7 2.4 230 2.02 0.207 0.181 1.433 0.317 3 0.295 0.013 5.3 50 710 7.6 275.7 14 71 2.6Std_Dev 4.5 4.3 428 0.96 0.143 0.133 1.019 0.658 5 0.648 0.021 2.9 25 113 0.2 15.1 4.9 6.6 3Count 53 60 59 34 60 60 60 60 60 60 60 55 55 56 57 7 55 5 4Min 1.2 0.2 32 0.1 0.021 0.018 0.14 0.009 0 0.001 0.002 6.2 63 16 6.8 67 10.6 65.3 0.15%'ile 1.3 0.8 62 0.49 0.025 0.02 0.18 0.08 2 0.07 0.003 7.4 70 130 7.1 67 12.5 65.3 0.125%'ile 1.8 1.4 220 1.29 0.03 0.023 0.32 0.215 7 0.186 0.008 9.2 89 178 7.6 67.5 13.9 68.1 0.2Median 2.5 2.2 320 1.75 0.038 0.027 0.41 0.284 11 0.26 0.016 10.3 102 192 7.8 69 15.2 72.9 0.275%'ile 4 6.1 580 2.42 0.047 0.03 0.54 0.414 17 0.39 0.033 11.9 114 207 8.1 69.8 16.9 80.5 0.495%'ile 8.4 16.5 1,060 3.4 0.056 0.038 0.805 0.628 27 0.596 0.048 13.2 140 246 8.3 74 18.6 84.4 0.6Max 57.2 138 2,700 4.32 0.22 0.045 8.5 7.704 285 7.6 0.093 176 188 467 9.2 75 21.8 86.2 0.6Mean 5.2 7.9 501 1.95 0.043 0.027 0.701 0.543 20 0.514 0.023 13.7 105 200 7.8 69.4 15.4 74.2 0.3Std_Dev 9.7 19.5 531 1.03 0.027 0.006 1.408 1.226 40 1.21 0.02 23.1 24 64 0.4 2.7 2.2 7.2 0.2Count 50 56 52 45 56 56 56 56 56 56 56 52 52 51 50 7 53 9 4Min 1.4 0.2 2 0.06 0.16 0.094 0.27 0.007 0 0 0.002 1.2 0 30 6.5 26 8.6 56.4 05%'ile 1.4 1.3 39 0.08 0.208 0.123 0.34 0.007 0 0 0.002 2.3 22 128 7.1 26 9.3 56.4 025%'ile 4.4 10 205 0.21 0.302 0.22 0.66 0.062 0 0.027 0.005 4.7 47 444 7.4 97.2 11.4 63.7 0Median 12 21 1,250 0.4 0.37 0.25 0.94 0.356 1 0.131 0.083 7 67 555 7.6 125 14.8 67.7 2.175%'ile 22.4 33.8 2,550 0.72 0.567 0.408 1.335 0.582 3 0.452 0.168 9.6 90 626 7.8 171 18.6 68.7 3.895%'ile 37.7 65 4,110 2.18 0.67 0.59 1.7 0.858 4 0.62 0.24 12.5 124 665 8.2 186 21.2 70.8 6.1Max 115 145 26,000 3.65 1.12 1.08 2.5 1.866 10 1.64 1 16.5 198 721 9.1 186 25.8 70.8 6.1Mean 18.1 29.9 2,040 0.71 0.436 0.322 1.036 0.388 2 0.261 0.111 7.4 72 505 7.7 124.8 15.3 65.8 2.2Std_Dev 20.4 31.7 3,730 0.95 0.201 0.184 0.474 0.371 2 0.305 0.157 3.6 37 171 0.5 61.7 4.3 5.5 2.5Count 51 55 52 19 55 55 55 55 55 55 55 53 54 55 54 5 54 5 5

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Min 0.9 1 5 0.9 0.086 0.06 0.39 0.007 0 0 0.002 0.2 2 476 7.4 220 5.5 NA 66.3 05%'ile 0.9 1.1 80 0.94 0.09 0.066 0.55 0.023 0 0.002 0.002 1.1 12 520 7.5 220 9.1 NA 66.3 025%'ile 1.6 1.7 180 1.02 0.146 0.116 1.015 0.398 1 0.146 0.006 6.9 68 657 7.7 270 12.9 NA 67.7 0Median 1.9 2.8 300 1.5 0.188 0.158 1.435 0.676 4 0.515 0.03 8.6 82 721 7.8 290 15.9 NA 71.2 075%'ile 2.8 3.9 700 1.95 0.295 0.265 2.1 1.087 12 1.03 0.066 10.6 107 808 7.9 300 19.7 NA 73.7 2.395%'ile 4.6 7.5 1,270 2.37 0.475 0.405 3.1 1.908 15 1.85 0.27 11.7 124 861 8.2 354 22.4 NA 75.5 8.3Max 9.1 9 2,000 2.8 0.56 0.47 4.3 3.014 17 2.8 0.41 15.4 174 955 8.5 360 24.3 NA 75.8 8.3Mean 2.5 3.4 512 1.55 0.24 0.2 1.682 0.831 6 0.735 0.07 8.2 83 727 7.8 288.3 16.1 NA 70.9 1.7Std_Dev 1.7 2.3 488 0.54 0.136 0.12 0.919 0.706 6 0.695 0.109 3.3 35 109 0.2 45.8 4.6 NA 3.5 3.7Count 32 40 38 28 40 40 40 40 40 40 40 36 36 37 38 6 37 NA 9 5Min 0.7 0.7 22 0.54 0.06 0.04 0.15 0.007 0 0 0.002 4.3 46 177 6 75 9.9 NA 68.3 1.85%'ile 1.5 0.7 41 0.55 0.075 0.057 0.181 0.008 0 0.001 0.002 5 55 218 7.5 75 10.6 NA 68.3 1.825%'ile 2.2 1.5 122 0.65 0.094 0.068 0.435 0.143 1 0.098 0.005 7.2 73 282 7.6 92.2 13.1 NA 68.6 4Median 2.9 3 230 0.85 0.116 0.088 0.62 0.381 5 0.31 0.02 9 88 371 7.8 100 16.6 NA 69.5 4.975%'ile 5 6 395 1.85 0.146 0.114 1.34 0.912 11 0.83 0.056 10.2 104 473 8.2 109.5 19 NA 74.9 9.495%'ile 8.7 9.2 1,580 2.41 0.174 0.14 2.09 1.434 15 1.309 0.084 11.5 119 557 8.6 135 21.3 NA 78.8 12.6Max 18.1 16 24,000 2.9 0.26 0.23 2.8 2.015 24 1.84 0.25 13.8 142 693 9.1 135 24.3 NA 78.8 12.6Mean 4 4.2 1,084 1.26 0.124 0.097 0.936 0.553 7 0.497 0.038 8.9 90 384 7.9 101.8 16.2 NA 71.8 6.5Std_Dev 3.2 3.5 3,557 0.75 0.042 0.04 0.707 0.551 6 0.515 0.049 2.2 22 124 0.5 21.4 3.7 NA 4.4 4.1Count 47 52 51 23 52 52 52 52 52 52 52 49 49 49 49 5 48 NA 5 5Min 0.4 0.2 50 0.6 0.028 0.017 0.19 0.007 0 0 0.002 0.3 3 163 7.5 84 6.7 NA 65.3 05%'ile 0.7 0.2 78 0.85 0.031 0.026 0.22 0.014 0 0.001 0.002 6.5 68 406 7.6 84 8.7 NA 65.3 025%'ile 1 0.8 280 1.7 0.051 0.042 0.283 0.035 1 0.024 0.002 9.2 92 518 8 225 10.9 NA 66.7 0.1Median 1.6 1.1 600 2.35 0.068 0.056 0.44 0.092 1 0.073 0.005 10.8 104 613 8.2 240 15.1 NA 69.7 0.175%'ile 2.2 1.5 1,450 3.1 0.09 0.084 0.615 0.314 6 0.305 0.013 12.1 115 648 8.4 267.5 18.5 NA 73.3 7.895%'ile 3.4 2.1 4,680 3.52 0.103 0.095 1.04 0.656 9 0.634 0.027 14.1 159 676 8.6 286 22.7 NA 75.2 15.4Max 6.7 7.2 120,000 4.1 0.144 0.119 2.1 0.986 11 0.96 0.043 16.1 175 760 9.1 290 25.7 NA 75.4 15.4Mean 1.8 1.3 3,714 2.36 0.072 0.063 0.549 0.215 3 0.199 0.011 10.6 107 582 8.2 229.1 15.3 NA 70 3.9Std_Dev 1.3 1.1 17,207 0.91 0.027 0.026 0.392 0.255 4 0.252 0.01 2.7 31 108 0.3 68 4.9 NA 4.2 7.7Count 47 50 48 34 51 51 51 51 51 51 51 49 49 49 48 7 48 NA 6 4Min 0.6 0.2 40 0.65 0.071 0.047 0.4 0.009 0 0 0.002 0.2 2 409 6.3 188 5.6 NA 67.1 05%'ile 0.8 0.5 51 0.88 0.078 0.064 0.426 0.018 0 0.001 0.002 1 8 493 7.1 188 9.4 NA 67.1 025%'ile 1.2 1.5 210 1.25 0.115 0.09 0.84 0.178 2 0.098 0.006 4.3 43 596 7.5 220 13.2 NA 67.6 0Median 1.6 2.5 320 2.15 0.139 0.122 1.4 0.772 6 0.615 0.028 6.8 72 693 7.7 260 16.6 NA 69.3 2.175%'ile 2.7 4.4 462 2.5 0.21 0.156 2.1 1.418 15 1.25 0.056 10.5 113 731 8.1 332.5 19.8 NA 71.8 7.795%'ile 4.2 6 720 3 0.406 0.26 2.79 2.057 22 1.979 0.254 14.7 148 828 8.5 372 22.7 NA 78.8 11.1Max 14 15.1 3,000 4.2 0.59 0.37 8.5 7.109 68 6.9 0.87 16.6 169 873 8.7 380 25.9 NA 78.8 11.1Mean 2.5 3.2 438 2.03 0.188 0.141 1.803 1.12 11 1.001 0.087 7.5 76 668 7.8 276.9 16.5 NA 70.5 3.8Std_Dev 2.4 2.7 511 0.84 0.127 0.082 1.697 1.502 14 1.484 0.165 4.6 48 107 0.5 69.6 4.6 NA 4.8 5.2Count 34 42 41 28 42 42 42 42 42 42 42 40 40 38 40 7 40 NA 5 4

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< 3 * median flows






Min 0.4 0.2 9 1 0.04 0.038 0.22 0.007 0 0 0.002 0.1 1 461 7 260 4.6 NA 63.8 0.15%'ile 0.5 0.2 15 1.09 0.06 0.042 0.298 0.007 0 0 0.002 0.2 2 507 7.2 260 8.1 NA 63.8 0.125%'ile 0.8 0.8 65 1.39 0.098 0.082 0.503 0.017 0 0.001 0.002 2.7 26 623 7.5 262.5 11.5 NA 64.7 0.2Median 1.2 1.3 140 2.1 0.151 0.157 1.07 0.069 0 0.05 0.005 4.3 45 706 7.6 270 15.6 NA 71.4 2.175%'ile 1.7 1.7 280 2.75 0.283 0.252 1.542 0.148 2 0.115 0.017 6.4 64 780 7.7 287.5 18.5 NA 77.2 5.195%'ile 2.8 2.9 391 3.6 0.52 0.42 1.84 0.33 5 0.32 0.027 8.6 77 836 7.8 298 21.9 NA 78 6.3Max 18.5 6.5 1,100 4.4 0.6 0.59 3.6 1.963 11 1.92 0.135 10.9 114 988 8.1 300 24.2 NA 78 6.3Mean 1.9 1.4 198 2.19 0.212 0.186 1.13 0.154 1 0.133 0.014 4.6 45 698 7.6 275.7 15.3 NA 71 2.6Std_Dev 2.9 1.1 201 0.98 0.153 0.142 0.688 0.308 2 0.305 0.023 2.8 26 113 0.2 15.1 4.7 NA 6.6 3Count 38 45 44 21 45 45 45 45 45 45 45 42 42 42 43 7 41 NA 5 4Min 1.2 0.2 32 0.5 0.021 0.018 0.14 0.009 0 0.001 0.002 7.3 69 16 7.1 67 10.6 NA 65.3 0.15%'ile 1.3 0.8 60 0.76 0.025 0.02 0.18 0.079 2 0.069 0.003 8 78 128 7.3 67 12.5 NA 65.3 0.125%'ile 1.8 1.4 210 1.32 0.03 0.023 0.32 0.214 7 0.18 0.008 9.6 92 178 7.6 67.5 14 NA 68.1 0.2Median 2.4 2 320 1.8 0.036 0.026 0.405 0.274 10 0.26 0.016 10.3 103 191 7.9 69 15.2 NA 72.9 0.275%'ile 3.9 5.3 500 2.48 0.044 0.03 0.49 0.369 15 0.33 0.031 12.3 116 206 8.1 69.8 16.7 NA 80.5 0.495%'ile 7.4 13.6 900 3.44 0.054 0.038 0.697 0.572 25 0.533 0.046 13.2 140 229 8.3 74 18.7 NA 84.4 0.6Max 44 45 2,700 4.32 0.091 0.044 1.05 0.87 46 0.83 0.067 176 188 298 9.2 75 21.8 NA 86.2 0.6Mean 4 5.4 471 2.03 0.039 0.027 0.436 0.315 13 0.288 0.021 14 107 191 7.9 69.4 15.4 NA 74.2 0.3Std_Dev 6.3 8.2 517 0.98 0.013 0.006 0.204 0.187 9 0.178 0.016 23.5 23 42 0.4 2.7 2.2 NA 7.2 0.2Count 48 54 50 43 54 54 54 54 54 54 54 50 50 49 48 7 51 NA 9 4Min 1.4 0.2 2 0.06 0.16 0.094 0.27 0.007 0 0 0.002 1.2 0 30 6.5 26 8.6 NA 56.4 05%'ile 1.4 1.2 38 0.07 0.201 0.121 0.328 0.007 0 0 0.002 2.2 22 123 7.1 26 9.4 NA 56.4 025%'ile 4.3 9.4 165 0.24 0.305 0.22 0.65 0.063 0 0.032 0.005 4.7 46 450 7.4 97.2 11.4 NA 63.7 0Median 11.8 20.2 1,300 0.4 0.37 0.255 0.93 0.298 1 0.131 0.084 6.6 66 562 7.6 125 15.9 NA 67.7 2.175%'ile 21 32.5 2,525 0.76 0.555 0.405 1.3 0.576 3 0.415 0.166 9.3 89 633 7.8 171 19 NA 68.7 3.895%'ile 30.9 64.3 4,320 2.53 0.673 0.599 1.662 0.84 4 0.578 0.255 12.2 117 669 8.2 186 21.3 NA 70.8 6.1Max 115 145 26,000 3.65 1.12 1.08 1.92 1.15 10 0.85 1 16.5 198 721 9.1 186 25.8 NA 70.8 6.1Mean 16.5 27.7 2,062 0.76 0.436 0.325 0.99 0.362 2 0.234 0.113 7.2 71 510 7.7 124.8 15.6 NA 65.8 2.2Std_Dev 18.8 28.7 3,826 0.99 0.203 0.187 0.428 0.314 2 0.24 0.16 3.5 37 169 0.5 61.7 4.3 NA 5.5 2.5Count 48 52 49 17 52 52 52 52 52 52 52 51 52 52 51 5 51 NA 5 5

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< median flows






Min 0.9 1 110 0.96 0.143 0.121 0.52 0.007 0 0 0.002 0.2 2 476 7.4 220 10.8 NA 66.3 05%'ile 0.9 1.1 115 0.97 0.144 0.124 0.55 0.012 0 0 0.002 0.5 5 493 7.4 220 11.8 NA 66.3 025%'ile 1.5 1.5 225 1.18 0.19 0.154 0.895 0.266 1 0.03 0.008 4.4 47 614 7.6 257.5 15.9 NA 67.3 0Median 1.8 1.8 335 1.62 0.295 0.265 1.275 0.458 2 0.39 0.047 6.9 68 672 7.7 280 18.9 NA 70.4 075%'ile 2.3 2.9 950 2 0.43 0.395 1.76 0.934 6 0.83 0.196 7.7 83 721 7.8 315 21.1 NA 74.2 2.395%'ile 3.2 3.7 1,250 2.39 0.535 0.44 2.7 1.791 12 1.64 0.365 8.8 104 816 7.9 360 22.6 NA 75.6 8.3Max 3.7 4.5 1,500 2.4 0.56 0.47 4.3 3.014 16 2.8 0.41 10.6 124 849 8.1 360 23.8 NA 75.8 8.3Mean 1.9 2.2 575 1.62 0.323 0.275 1.495 0.728 4 0.58 0.113 5.9 64 670 7.7 286 18.4 NA 70.7 1.7Std_Dev 0.8 1 443 0.5 0.144 0.123 0.916 0.761 5 0.744 0.14 3 34 102 0.2 50.8 3.5 NA 3.7 3.7Count 17 20 20 16 20 20 20 20 20 20 20 17 17 18 19 5 18 NA 8 5Min 0.7 0.7 22 0.54 0.06 0.04 0.15 0.007 0 0 0.002 4.3 46 177 7.4 75 9.9 NA 68.3 1.85%'ile 0.9 0.7 29 0.54 0.073 0.044 0.159 0.007 0 0 0.002 4.6 50 197 7.4 75 12.3 NA 68.3 1.825%'ile 1.7 1.5 120 0.57 0.094 0.069 0.33 0.023 0 0.01 0.004 6.7 65 258 7.6 92.2 17.4 NA 68.6 4Median 2.4 2 260 1.6 0.122 0.101 0.46 0.155 1 0.128 0.01 7.4 80 285 7.8 100 18.6 NA 69.5 4.975%'ile 3.4 4.2 800 2.3 0.148 0.119 0.595 0.338 4 0.295 0.048 9.9 103 336 8.2 109.5 20.4 NA 74.9 9.495%'ile 7.2 7 4,000 2.88 0.172 0.147 0.814 0.451 8 0.367 0.073 10.5 117 384 8.4 135 22.2 NA 78.8 12.6Max 18.1 10.3 24,000 2.9 0.24 0.21 1.09 0.708 9 0.43 0.25 11.2 132 494 8.9 135 24.3 NA 78.8 12.6Mean 3.4 3.2 1,692 1.56 0.126 0.102 0.48 0.199 3 0.156 0.031 7.9 83 299 7.9 101.8 18.6 NA 71.8 6.5Std_Dev 3.7 2.5 4,764 0.97 0.043 0.043 0.234 0.186 3 0.143 0.052 2 23 73 0.4 21.4 3.2 NA 4.4 4.1Count 23 28 27 10 28 28 28 28 28 28 28 25 25 25 25 5 25 NA 5 5Min 0.4 0.2 190 0.6 0.028 0.018 0.19 0.012 0 0.001 0.002 6.3 67 163 7.8 84 11.8 NA 65.3 05%'ile 0.5 0.4 250 0.64 0.04 0.03 0.207 0.013 0 0.001 0.002 6.4 68 206 7.8 84 12.4 NA 65.3 025%'ile 0.8 0.8 515 1.23 0.06 0.05 0.272 0.018 0 0.011 0.004 8.1 84 478 7.9 220 15.8 NA 66.7 0.1Median 1.2 0.9 1,100 2.27 0.083 0.073 0.36 0.055 1 0.044 0.005 9.6 104 510 8.2 240 18.4 NA 69.7 0.175%'ile 1.9 1.6 3,425 3.03 0.098 0.086 0.492 0.117 1 0.071 0.013 11.1 118 611 8.4 260 20.6 NA 73.3 7.895%'ile 3.7 2.5 5,360 3.61 0.126 0.107 0.608 0.22 3 0.189 0.032 14.2 172 635 8.5 269 24.2 NA 75.2 15.4Max 6.5 7.2 120,000 4.1 0.144 0.119 1.72 0.236 3 0.22 0.043 14.8 175 714 9.1 270 25.7 NA 75.4 15.4Mean 1.7 1.5 7,535 2.22 0.082 0.071 0.429 0.077 1 0.061 0.011 9.9 108 516 8.2 219 18.4 NA 70 3.9Std_Dev 1.5 1.5 25,832 1.08 0.03 0.027 0.321 0.075 1 0.07 0.012 2.6 34 131 0.3 68.4 3.8 NA 4.2 7.7Count 19 21 21 12 21 21 21 21 21 21 21 20 20 20 20 6 20 NA 6 4Min 0.6 0.2 40 0.65 0.101 0.074 0.4 0.009 0 0 0.002 0.2 2 409 7 188 10 NA 67.1 05%'ile 0.7 0.2 64 0.69 0.119 0.084 0.436 0.012 0 0.001 0.002 0.5 6 447 7.1 188 11.3 NA 67.1 025%'ile 1.2 1.5 270 1.11 0.146 0.124 0.78 0.11 1 0.007 0.006 1.6 16 584 7.4 210 16.2 NA 67.6 0Median 1.5 2 330 2.1 0.21 0.152 1.34 0.487 3 0.124 0.044 4.4 48 675 7.6 285 18.4 NA 69.3 2.175%'ile 2.9 4.1 450 2.68 0.31 0.25 1.93 1.074 7 0.79 0.2 5.4 58 722 7.7 340 21.2 NA 71.8 7.795%'ile 5.4 6.3 715 3 0.5 0.353 4.44 3.143 26 2.885 0.424 8.9 101 742 8 376 23.4 NA 78.8 11.1Max 14 15.1 900 3 0.59 0.37 8.5 7.109 68 6.9 0.87 9.8 119 831 8.5 380 25.9 NA 78.8 11.1Mean 2.7 3.3 370 1.88 0.258 0.188 1.932 1.115 9 0.921 0.144 4.3 47 648 7.6 281.3 18.4 NA 70.5 3.8Std_Dev 3.1 3.2 207 0.85 0.142 0.088 2.213 1.968 18 1.944 0.213 2.8 33 103 0.3 75.2 4 NA 4.8 5.2Count 19 22 22 13 22 22 22 22 22 22 22 21 21 20 21 6 21 NA 5 4

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< median flows






Min 0.4 0.2 15 1 0.04 0.038 0.22 0.007 0 0 0.002 0.1 1 461 7 260 10.9 NA 63.8 0.15%'ile 0.5 0.2 18 1.03 0.06 0.041 0.292 0.007 0 0 0.002 0.1 1 502 7.1 260 11.1 NA 63.8 0.125%'ile 0.9 0.8 80 1.38 0.1 0.088 0.398 0.014 0 0.001 0.002 1.5 18 598 7.5 260 14.5 NA 64.7 0.2Median 1.3 1.3 200 1.97 0.182 0.174 0.86 0.048 0 0.006 0.005 3.8 36 650 7.6 275 17.3 NA 71.4 2.175%'ile 1.8 1.5 322 3.5 0.318 0.272 1.472 0.132 1 0.088 0.017 5.1 52 738 7.7 290 19.3 NA 77.2 5.195%'ile 2.7 2.9 412 3.68 0.532 0.452 1.684 0.293 4 0.278 0.044 6.7 66 810 7.8 299 22 NA 78 6.3Max 18.5 3.6 1,100 4.4 0.6 0.59 2.2 0.65 11 0.62 0.135 10.9 114 855 8.1 300 24.2 NA 78 6.3Mean 2 1.3 234 2.27 0.229 0.203 0.922 0.103 1 0.08 0.015 3.7 38 661 7.6 276.7 17.1 NA 71 2.6Std_Dev 3.4 0.9 215 1.11 0.166 0.153 0.566 0.142 2 0.14 0.026 2.5 25 102 0.2 16.3 3.7 NA 6.6 3Count 26 33 33 14 33 33 33 33 33 33 33 30 30 30 31 6 29 NA 5 4Min 1.2 0.2 32 0.5 0.025 0.02 0.14 0.009 0 0.001 0.002 7.7 77 16 7.1 67 13.6 NA 65.3 0.15%'ile 1.2 0.6 60 0.71 0.025 0.02 0.171 0.02 1 0.009 0.002 8 77 92 7.2 67 14 NA 65.3 0.125%'ile 1.5 1.2 230 1.34 0.031 0.024 0.25 0.151 4 0.131 0.005 9.7 96 169 7.7 67 15 NA 67.3 0.2Median 2 1.6 320 1.86 0.038 0.027 0.36 0.23 8 0.205 0.01 10.4 104 180 8 69 16 NA 73.7 0.275%'ile 2.6 3.3 500 2.5 0.05 0.032 0.41 0.3 12 0.28 0.019 12.4 119 188 8.2 70 17.9 NA 80.9 0.495%'ile 5.8 15.2 1,000 3.31 0.057 0.039 0.536 0.355 15 0.333 0.04 13.2 139 192 8.4 74.5 19.2 NA 84.9 0.6Max 9.8 45 2,700 3.8 0.091 0.044 0.58 0.497 24 0.48 0.05 176 159 206 9.2 75 21.8 NA 86.2 0.6Mean 2.7 5 517 1.98 0.041 0.029 0.344 0.229 9 0.209 0.015 16.4 108 169 8 69.5 16.4 NA 74.4 0.3Std_Dev 2.1 9.2 616 0.91 0.015 0.007 0.119 0.113 6 0.111 0.013 31.3 21 37 0.4 2.9 2 NA 7.7 0.2Count 27 32 30 24 32 32 32 32 32 32 32 28 28 27 27 6 29 NA 8 4Min 1.4 0.2 2 0.1 0.16 0.094 0.27 0.007 0 0 0.002 1.2 13 30 6.5 26 11 NA 56.4 05%'ile 1.6 1.5 36 0.1 0.24 0.119 0.28 0.007 0 0 0.002 2.5 24 73 6.8 26 11.4 NA 56.4 025%'ile 9.1 14 650 0.25 0.35 0.24 0.61 0.019 0 0.003 0.005 3.9 41 380 7.4 97.2 14.7 NA 63.7 0Median 18.1 24.5 1,600 0.38 0.455 0.335 0.78 0.165 0 0.065 0.052 5.7 59 505 7.8 125 17.7 NA 67.7 2.175%'ile 26.9 34 3,375 0.65 0.62 0.48 1.28 0.377 2 0.131 0.161 8.5 88 597 8 171 20.2 NA 68.7 3.895%'ile 42.2 60.5 4,920 2.2 0.805 0.64 1.78 0.582 3 0.31 0.31 12.9 119 654 8.5 186 21.7 NA 70.8 6.1Max 115 145 26,000 3.65 1.12 1.08 1.92 1.15 10 0.5 1 16.5 198 721 9.1 186 23.7 NA 70.8 6.1Mean 21.2 30.5 2,838 0.7 0.508 0.38 0.929 0.242 1 0.106 0.123 6.7 70 461 7.8 124.8 17.3 NA 65.8 2.2Std_Dev 22.5 28.8 4,796 1.06 0.226 0.213 0.479 0.269 2 0.128 0.2 3.8 40 187 0.6 61.7 3.6 NA 5.5 2.5Count 29 30 29 10 30 30 30 30 30 30 30 29 30 30 29 5 30 NA 5 5

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LQ flows






Min 0.9 1 110 0.96 0.143 0.121 0.58 0.007 0 0 0.002 0.2 2 519 7.4 220 10.8 NA 66.3 05%'ile 1 1 114 0.97 0.143 0.123 0.654 0.011 0 0 0.002 0.5 4 541 7.4 220 11.5 NA 66.3 025%'ile 1.5 1.4 212 1.3 0.191 0.14 0.902 0.329 1 0.011 0.01 3.7 37 641 7.6 257.5 15.9 NA 67 0Median 1.9 1.8 300 1.64 0.31 0.29 1.23 0.436 2 0.36 0.063 6.9 68 682 7.7 280 18.6 NA 69.5 075%'ile 2.2 3.3 700 1.9 0.458 0.402 1.552 0.992 7 0.908 0.26 7.4 82 716 7.8 315 20.6 NA 72.8 2.395%'ile 3 3.7 1,220 2.32 0.538 0.452 3.036 2.065 13 1.856 0.38 8.9 103 810 7.9 360 22.4 NA 75.3 8.3Max 3.7 4.5 1,500 2.4 0.56 0.47 4.3 3.014 16 2.8 0.41 10.6 124 849 8.1 360 22.6 NA 75.8 8.3Mean 1.9 2.2 482 1.65 0.332 0.282 1.509 0.771 4 0.608 0.126 5.8 62 683 7.7 286 18 NA 70.1 1.7Std_Dev 0.7 1.1 413 0.45 0.151 0.13 0.955 0.81 5 0.799 0.148 3.1 34 82 0.2 50.8 3.4 NA 3.5 3.7Count 14 17 17 13 17 17 17 17 17 17 17 15 15 15 16 5 16 NA 7 5Min 1.1 0.7 22 0.55 0.06 0.04 0.15 0.007 0 0 0.002 4.7 52 177 7.5 75 15 NA 68.3 1.85%'ile 1.2 0.7 29 0.55 0.064 0.041 0.152 0.007 0 0 0.002 4.8 52 182 7.5 75 15.5 NA 68.3 1.825%'ile 1.6 1.3 90 1.56 0.094 0.07 0.198 0.011 0 0.003 0.002 6.8 77 232 7.7 86.5 18.4 NA 68.6 4Median 2.3 2.3 160 2.1 0.127 0.107 0.37 0.024 0 0.011 0.005 9.2 97 276 7.9 99.5 19.8 NA 69.5 4.975%'ile 3.4 4.3 440 2.44 0.137 0.118 0.465 0.254 2 0.173 0.045 10.1 112 303 8.2 118 20.9 NA 74.9 9.495%'ile 3.6 7.7 1,300 2.85 0.162 0.138 0.58 0.426 8 0.31 0.078 10.9 120 327 8.4 135 22.1 NA 78.8 12.6Max 3.6 10.3 2,000 2.85 0.17 0.146 0.94 0.459 9 0.37 0.119 11.2 132 358 8.6 135 24.3 NA 78.8 12.6Mean 2.4 3.4 419 1.94 0.12 0.096 0.373 0.13 2 0.094 0.025 8.6 93 272 8 102.2 19.6 NA 71.8 6.5Std_Dev 0.9 2.8 563 0.85 0.032 0.033 0.212 0.171 3 0.134 0.036 2.1 25 50 0.3 24.7 2.3 NA 4.4 4.1Count 14 15 15 5 15 15 15 15 15 15 15 14 14 14 14 4 14 NA 5 5Min 0.7 0.2 190 0.6 0.028 0.018 0.19 0.012 0 0.001 0.002 6.3 67 163 7.8 84 11.8 NA 65.3 05%'ile 0.7 0.4 240 0.62 0.038 0.027 0.204 0.013 0 0.001 0.002 6.4 67 197 7.8 84 12.2 NA 65.3 025%'ile 0.8 0.8 505 1.26 0.059 0.048 0.258 0.019 0 0.01 0.003 7.8 80 470 7.9 220 15.6 NA 66.7 0.1Median 1.2 0.9 1,100 2.4 0.068 0.066 0.37 0.055 1 0.044 0.005 9.3 98 503 8.2 240 18.2 NA 69.7 0.175%'ile 2.1 1.7 4,075 3.06 0.098 0.084 0.498 0.124 1 0.096 0.012 10.5 115 613 8.3 260 20.6 NA 73.3 7.895%'ile 3.8 2.7 5,440 3.68 0.132 0.111 0.612 0.223 3 0.199 0.026 13.8 164 637 8.5 269 24.1 NA 75.2 15.4Max 6.5 7.2 120,000 4.1 0.144 0.119 1.72 0.236 3 0.22 0.038 14.4 175 714 9.1 270 25.7 NA 75.4 15.4Mean 1.8 1.5 8,133 2.3 0.081 0.069 0.439 0.079 1 0.063 0.01 9.6 104 507 8.2 219 18.1 NA 70 3.9Std_Dev 1.5 1.5 27,155 1.09 0.031 0.028 0.336 0.077 1 0.073 0.01 2.4 32 135 0.3 68.4 3.9 NA 4.2 7.7Count 17 19 19 11 19 19 19 19 19 19 19 18 18 18 18 6 18 NA 6 4Min 0.6 0.2 40 0.65 0.101 0.074 0.4 0.009 0 0 0.002 0.2 2 484 7 188 10 NA 67.1 05%'ile 0.7 0.2 58 0.65 0.115 0.081 0.472 0.011 0 0.001 0.002 0.4 5 510 7.1 188 11 NA 67.1 025%'ile 1.2 1.6 255 1.13 0.172 0.124 0.792 0.12 1 0.004 0.008 1.6 15 597 7.3 210 15.8 NA 67.6 0Median 1.5 2 320 1.8 0.22 0.16 1.3 0.403 3 0.11 0.044 4.2 43 676 7.5 285 18.1 NA 69.3 2.175%'ile 3 4.2 432 2.6 0.378 0.258 1.89 0.921 5 0.712 0.223 5 56 726 7.7 340 20.8 NA 71.8 7.795%'ile 6.1 6.9 730 2.95 0.53 0.356 6.18 4.776 39 4.384 0.448 7.8 88 748 8.1 376 23 NA 78.8 11.1Max 14 15.1 900 3 0.59 0.37 8.5 7.109 68 6.9 0.87 9.8 110 831 8.5 380 23.8 NA 78.8 11.1Mean 2.8 3.4 359 1.82 0.274 0.196 2.01 1.157 9 0.938 0.163 3.8 41 665 7.6 281.3 18 NA 70.5 3.8Std_Dev 3.3 3.4 222 0.85 0.147 0.092 2.364 2.112 19 2.088 0.224 2.7 30 85 0.4 75.2 3.9 NA 4.8 5.2Count 16 19 19 10 19 19 19 19 19 19 19 18 18 17 18 6 18 NA 5 4

Awan

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LQ flows






Min 0.4 0.2 15 1 0.04 0.038 0.22 0.007 0 0 0.002 0.1 1 461 7 260 10.9 NA 63.8 0.15%'ile 0.5 0.2 15 1.03 0.057 0.041 0.279 0.007 0 0 0.002 0.1 1 491 7 260 11 NA 63.8 0.125%'ile 0.8 0.6 80 1.34 0.096 0.077 0.368 0.014 0 0.001 0.002 1.5 15 591 7.5 260 14.1 NA 64.7 0.2Median 1.3 1.3 150 1.64 0.148 0.12 0.65 0.025 0 0.005 0.005 3 34 640 7.6 275 17.9 NA 71.4 2.175%'ile 2 1.8 322 2.83 0.305 0.258 1.042 0.147 1 0.102 0.017 4.8 46 704 7.7 290 19.4 NA 77.2 5.195%'ile 2.8 3 448 3.76 0.528 0.444 1.54 0.311 4 0.302 0.046 5.6 60 828 7.8 299 22.1 NA 78 6.3Max 18.5 3.6 1,100 4.4 0.6 0.59 2.2 0.65 11 0.62 0.135 10.9 114 855 8.1 300 24.2 NA 78 6.3Mean 2.2 1.4 232 2.17 0.214 0.187 0.775 0.109 1 0.084 0.017 3.3 34 645 7.6 276.7 17.3 NA 71 2.6Std_Dev 3.8 1 234 1.08 0.166 0.151 0.509 0.155 3 0.155 0.029 2.4 25 103 0.2 16.3 3.9 NA 6.6 3Count 21 27 27 13 27 27 27 27 27 27 27 25 25 25 26 6 24 NA 5 4Min 1.2 0.6 32 0.5 0.028 0.02 0.14 0.009 0 0.001 0.002 8 77 16 7.3 67 13.6 NA 65.3 0.15%'ile 1.2 0.7 40 0.58 0.029 0.021 0.149 0.011 0 0.002 0.002 8 78 52 7.4 67 13.7 NA 65.3 0.125%'ile 1.4 1.1 240 1.42 0.035 0.026 0.19 0.093 3 0.084 0.005 9 91 174 7.9 67.5 15.2 NA 67.9 0.1Median 2.1 1.4 315 2.05 0.04 0.028 0.28 0.151 4 0.131 0.007 10.3 104 180 8 69 16.9 NA 72.9 0.275%'ile 2.6 2.5 475 2.75 0.05 0.038 0.375 0.233 8 0.206 0.012 12.9 122 184 8.3 69.8 19.1 NA 82.9 0.295%'ile 3.8 3.6 790 3.52 0.057 0.039 0.39 0.298 11 0.278 0.023 14.7 149 188 8.7 70 19.3 NA 86.2 0.2Max 9.8 26 2,700 3.8 0.091 0.044 0.43 0.302 13 0.29 0.042 176 159 192 9.2 70 21.8 NA 86.2 0.2Mean 2.6 3.1 484 2.13 0.044 0.032 0.283 0.161 5 0.145 0.01 21.6 109 169 8.1 68.7 17 NA 75 0.2Std_Dev 2.1 6.2 626 0.96 0.015 0.007 0.099 0.093 4 0.09 0.01 42.8 25 43 0.4 1.5 2.4 NA 8.8 0.1Count 16 16 16 12 16 16 16 16 16 16 16 15 15 15 15 3 16 NA 5 3Min 2.8 7.3 2 0.1 0.25 0.094 0.28 0.007 0 0 0.002 1.2 13 73 7.2 26 13.9 NA 67.7 05%'ile 2.8 7.8 4 0.1 0.253 0.099 0.293 0.007 0 0 0.002 1.3 14 75 7.2 26 13.9 NA 67.7 025%'ile 6.7 26 800 0.11 0.385 0.242 0.66 0.009 0 0.001 0.002 3.6 39 350 7.5 50.8 17.5 NA 67.8 0.5Median 19.1 32 1,400 0.12 0.62 0.46 0.82 0.035 0 0.006 0.005 4.4 47 419 7.7 125 19.8 NA 68 2.175%'ile 29.6 54.5 3,525 0.22 0.845 0.64 1.392 0.211 1 0.069 0.098 6 61 542 8 155.8 21.3 NA 70.1 2.895%'ile 81.5 107.8 13,160 0.25 1.054 0.888 1.86 0.541 4 0.386 0.181 11.2 121 716 8.6 166 22.7 NA 70.8 3.1Max 115 145 26,000 0.25 1.12 1.08 1.86 0.544 6 0.5 0.21 16.5 198 721 9.1 166 23.7 NA 70.8 3.1Mean 27.8 46.7 3,950 0.16 0.631 0.465 1.007 0.145 1 0.088 0.05 5.5 60 429 7.8 105.7 19.1 NA 68.8 1.7Std_Dev 33.5 38.4 7,461 0.08 0.285 0.291 0.526 0.208 2 0.164 0.076 4 48 206 0.5 72 3 NA 1.7 1.6Count 10 11 11 3 11 11 11 11 11 11 11 11 11 11 11 3 11 NA 3 3

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Appendix C Trend analysis results for water quality variables 6-year trend analysis

Site Variable Sample period n Min Median Max Trend p

Trend PAC

Awanui Strm

TN (mg⁄l) 17⁄7⁄12-7⁄6⁄18 66 0.39 1.985 8.6 0.76 -1.255 TP (mg⁄l) 17⁄7⁄12-7⁄6⁄18 65 0.086 0.2 0.82 0.90 -0.671 DIN (mg/l) 17⁄7⁄12-7⁄6⁄18 65 0.014 1.09 4.98 0.71 -2.332 DRP (mg/l) 17⁄7⁄12-7⁄6⁄18 65 0.06 0.169 0.62 0.58 -3.039 NO3-N (mg/l) 17⁄7⁄12-7⁄6⁄18 66 0.001 0.995 4.9 1.00 0 Black Disc 17⁄7⁄12-7⁄6⁄18 49 0.05 1.25 2.4 0.72 -4.212 Turbidity (NTU) 17⁄7⁄12-7⁄6⁄18 54 0.81 2.495 185 0.31 -4.63 E. coli (cfu ⁄ 100mL) 17⁄7⁄12-7⁄6⁄18 64 5 250 25000 0.85 2.996 NH4-N (mg/l) 17⁄7⁄12-7⁄6⁄18 66 0.005 0.04 0.57 0.00 -20.845 SS (mg/l) 17⁄7⁄12-7⁄6⁄18 66 1.5 3.5 188 0.95 0

Clive Rv

TN (mg⁄l) 17⁄7⁄12-7⁄6⁄18 68 0.15 0.755 7.4 0.22 4.327 TP (mg⁄l) 17⁄7⁄12-7⁄6⁄18 68 0.06 0.117 0.54 0.29 1.669 DIN (mg/l) 17⁄7⁄12-7⁄6⁄18 68 0.014 0.43 5.89 0.72 0.051 DRP (mg/l) 17⁄7⁄12-7⁄6⁄18 68 0.04 0.095 0.23 0.52 1.946 NO3-N (mg/l) 17⁄7⁄12-7⁄6⁄18 68 0.001 0.365 5.6 0.72 0.29 Black Disc 29⁄11⁄12-7⁄6⁄18 31 0.06 1.125 2.95 0.77 -2.133 Turbidity (NTU) 17⁄7⁄12-7⁄6⁄18 59 0.68 3.09 132 0.25 -3.28 E. coli (cfu ⁄ 100mL) 17⁄7⁄12-7⁄6⁄18 66 30 230 24000 0.16 8.586 NH4-N (mg/l) 17⁄7⁄12-7⁄6⁄18 68 0.005 0.027 0.25 0.66 0 SS (mg/l) 17⁄7⁄12-7⁄6⁄18 68 1.5 1.5 154 0.18 0

Herehere Strm

TN (mg⁄l) 17⁄7⁄12-7⁄6⁄18 68 0.16 0.485 7.2 0.24 3.63 TP (mg⁄l) 17⁄7⁄12-7⁄6⁄18 68 0.027 0.074 0.52 0.20 4.883 DIN (mg/l) 17⁄7⁄12-7⁄6⁄18 68 0.014 0.127 4.454 1.00 -0.099 DRP (mg/l) 17⁄7⁄12-7⁄6⁄18 68 0.017 0.062 0.26 0.05 6.643 NO3-N (mg/l) 17⁄7⁄12-7⁄6⁄18 68 0.001 0.105 4.3 0.60 1.419 Black Disc 17⁄7⁄12-7⁄6⁄18 47 0.1 2.3 4.15 0.10 5.818 Turbidity (NTU) 17⁄7⁄12-7⁄6⁄18 60 0.39 1.835 306.7 0.12 -8.151 E. coli (cfu ⁄ 100mL) 17⁄7⁄12-7⁄6⁄18 64 50 600 120000 0.53 5.395 NH4-N (mg/l) 17⁄7⁄12-7⁄6⁄18 68 0.005 0.005 0.117 0.08 0 SS (mg/l) 13⁄8⁄12-7⁄6⁄18 66 1.5 1.5 250 0.01 0

Karewarewa Strm

TN (mg⁄l) 17⁄7⁄12-7⁄6⁄18 68 0.4 1.983 8.5 0.16 -6.83 TP (mg⁄l) 17⁄7⁄12-7⁄6⁄18 68 0.071 0.159 1.21 0.07 -5.936 DIN (mg/l) 17⁄7⁄12-7⁄6⁄18 68 0.014 1.349 7.109 0.52 -3.299 DRP (mg/l) 17⁄7⁄12-7⁄6⁄18 68 0.047 0.125 1.29 0.06 -6.289 NO3-N (mg/l) 17⁄7⁄12-7⁄6⁄18 68 0.001 1.27 6.9 0.77 -0.239 Black Disc 17⁄7⁄12-7⁄6⁄18 51 0.04 1.6 3.55 0.32 5.853 Turbidity (NTU) 17⁄7⁄12-7⁄6⁄18 57 0.6 2.56 706 0.25 -6.22 E. coli (cfu ⁄ 100mL) 17⁄7⁄12-7⁄6⁄18 67 40 300 38000 0.19 -7.302 NH4-N (mg/l) 17⁄7⁄12-7⁄6⁄18 68 0.005 0.043 0.98 0.00 -23.933



Trend PAC

SS (mg/l) 17⁄7⁄12-7⁄6⁄18 68 1.5 3.4 320 0.66 0

Mangaone Rv at Rissington

TN (mg⁄l) 19⁄7⁄12-12⁄6⁄18 67 0.11 0.46 13.1 0.00 7.737 TP (mg⁄l) 19⁄7⁄12-12⁄6⁄18 67 0.013 0.033 3.2 0.07 3.079 DIN (mg/l) 19⁄7⁄12-12⁄6⁄18 67 0.014 0.338 0.906 0.09 6.674 DRP (mg/l) 19⁄7⁄12-12⁄6⁄18 67 0.002 0.026 0.068 0.10 3.907 NO3-N (mg/l) 19⁄7⁄12-12⁄6⁄18 67 0.001 0.33 0.89 0.11 6.292 Black Disc 19⁄7⁄12-12⁄6⁄18 65 0.01 2.1 4.3 0.95 0.791 Turbidity (NTU) 19⁄7⁄12-12⁄6⁄18 64 0.66 2.49 3200 0.15 6.737 E. coli (cfu ⁄ 100mL) 19⁄7⁄12-12⁄6⁄18 66 2 50 12000 0.31 6.677 NH4-N (mg/l) 19⁄7⁄12-12⁄6⁄18 67 0.005 0.005 0.075 0.12 0 SS (mg/l) 19⁄7⁄12-12⁄6⁄18 67 1.5 1.5 4600 0.20 0

Mangatutu Strm

TN (mg⁄l) 20⁄11⁄12-12⁄6⁄18 65 0.24 0.56 7.1 0.00 8.79 TP (mg⁄l) 20⁄11⁄12-12⁄6⁄18 65 0.014 0.025 3.8 0.12 3.008 DIN (mg/l) 20⁄11⁄12-12⁄6⁄18 62 0.127 0.389 0.907 0.02 9.427 DRP (mg/l) 20⁄11⁄12-12⁄6⁄18 65 0.002 0.02 0.042 0.24 1.657 NO3-N (mg/l) 20⁄11⁄12-12⁄6⁄18 65 0.12 0.38 0.9 0.01 10.59 Black Disc 20⁄11⁄12-12⁄6⁄18 62 0.01 1.525 4.65 0.51 -3.459 Turbidity (NTU) 20⁄11⁄12-12⁄6⁄18 63 0.78 3.21 3500 0.52 3.112 E. coli (cfu ⁄ 100mL) 20⁄11⁄12-12⁄6⁄18 64 1 43.5 24000 0.38 6.288 NH4-N (mg/l) 20⁄11⁄12-12⁄6⁄18 65 0.005 0.005 0.064 0.58 0 SS (mg/l) 20⁄11⁄12-12⁄6⁄18 65 1.5 4 5700 0.19 0

Maraekakaho Strm

TN (mg⁄l) 15⁄11⁄12-5⁄6⁄18 64 0.14 0.465 3.4 0.90 -0.592 TP (mg⁄l) 15⁄11⁄12-5⁄6⁄18 64 0.004 0.026 0.22 0.65 0.988 DIN (mg/l) 15⁄11⁄12-5⁄6⁄18 58 0.023 0.224 2.72 0.05 -8.807 DRP (mg/l) 15⁄11⁄12-5⁄6⁄18 64 0.002 0.023 0.143 0.66 3.244 NO3-N (mg/l) 15⁄11⁄12-5⁄6⁄18 64 0.017 0.215 2.7 0.05 -9.456 Black Disc 4⁄12⁄12-5⁄6⁄18 53 0.12 3.2 9.25 0.94 -0.913 Turbidity (NTU) 15⁄11⁄12-2⁄5⁄18 58 0.34 0.905 56.1 1.00 0 E. coli (cfu ⁄ 100mL) 15⁄11⁄12-5⁄6⁄18 61 3 68 7000 0.32 8.026 NH4-N (mg/l) 15⁄11⁄12-5⁄6⁄18 64 0.005 0.005 0.03 0.39 0 SS (mg/l) 15⁄11⁄12-5⁄6⁄18 64 1.5 1.5 59 0.27 0

Ngaruroro Rv at

Chesterhope NIWA

TN (mg⁄l) 3⁄7⁄12-11⁄6⁄18 67 0 0.143 0.753 0.087 -7.818 TP (mg⁄l) 3⁄7⁄12-11⁄6⁄18 66 0.003 0.02 0.2 0.485 -3.077 DIN (mg⁄l) 3⁄7⁄12-11⁄6⁄18 67 0.004 0.082 0.61 0.171 -9.249 DRP (mg⁄l) 3⁄7⁄12-11⁄6⁄18 67 0.002 0.007 0.017 0.286 -3.581 NO3-N (mg/l) Black Disc 3⁄7⁄12-11⁄6⁄18 67 0.08 0.95 5.25 0.263 6.81 Turbidity (NTU) 3⁄7⁄12-11⁄6⁄18 67 0.56 4.48 136 0.585 -3.872 E. coli (cfu ⁄ 100mL) 3⁄7⁄12-11⁄6⁄18 67 2 20.1 1986.3 0.961 0 NH4-N (mg/l) 3⁄7⁄12-11⁄6⁄18 67 0 0.004 0.008 0.318 0 SS (mg/l)



Trend PAC

Ngaruroro Rv at Fernhill

TN (mg⁄l) 3⁄7⁄12-5⁄6⁄18 70 0.052 0.175 5.7 0.18 3.314 TP (mg⁄l) 3⁄7⁄12-5⁄6⁄18 70 0.002 0.012 1.83 0.16 6.468 DIN (mg/l) 3⁄7⁄12-5⁄6⁄18 65 0.014 0.11 0.622 0.49 2.685 DRP (mg/l) 3⁄7⁄12-5⁄6⁄18 70 0.002 0.008 0.091 0.17 7.513 NO3-N (mg/l) 3⁄7⁄12-5⁄6⁄18 71 0.001 0.091 0.56 0.29 3.245 Black Disc 3⁄7⁄12-13⁄4⁄18 62 0 0.845 6.4 0.05 -6.408 Turbidity (NTU) 3⁄7⁄12-2⁄5⁄18 64 0.36 6.505 562 0.19 5.443 E. coli (cfu ⁄ 100mL) 3⁄7⁄12-5⁄6⁄18 67 3 37 8000 0.01 15.983 NH4-N (mg/l) 3⁄7⁄12-5⁄6⁄18 71 0.005 0.005 0.048 0.22 0 SS (mg/l) 3⁄7⁄12-5⁄6⁄18 70 1.5 5 1690 0.12 0

Ngaruroro Rv at

Kuripapango NIWA

TN (mg⁄l) 3⁄7⁄12-7⁄5⁄18 65 0 0.046 0.229 0.411 2.432 TP (mg⁄l) 3⁄7⁄12-7⁄5⁄18 64 0.002 0.004 0.067 0.375 0 DIN (mg⁄l) 3⁄7⁄12-7⁄5⁄18 65 0.002 0.01 0.042 0.087 10.087 DRP (mg⁄l) 3⁄7⁄12-7⁄5⁄18 65 0 0.002 0.004 0.646 1.374 NO3-N (mg/l) Black Disc 3⁄7⁄12-7⁄5⁄18 64 0.17 5.9 11.1 0.817 0.475 Turbidity (NTU) 3⁄7⁄12-7⁄5⁄18 65 0.28 1.01 49.2 0.679 -1.792 E. coli (cfu ⁄ 100mL) 3⁄7⁄12-7⁄5⁄18 65 0 3.1 341 0.305 2.038 NH4-N (mg/l) 3⁄7⁄12-7⁄5⁄18 65 0 0.002 0.009 0.059 0 SS (mg/l)

Ngaruroro Rv at

Whanawhana

TN (mg⁄l) 3⁄7⁄12-5⁄6⁄18 71 0.054 0.055 3 0.34 0 TP (mg⁄l) 3⁄7⁄12-5⁄6⁄18 71 0.002 0.002 0.87 0.10 0 DIN (mg/l) 3⁄7⁄12-5⁄6⁄18 67 0.014 0.027 0.956 0.81 0 DRP (mg/l) 3⁄7⁄12-5⁄6⁄18 70 0.002 0.002 0.012 0.66 0 NO3-N (mg/l) 3⁄7⁄12-5⁄6⁄18 71 0.001 0.018 0.95 0.29 4.836 Black Disc 3⁄7⁄12-5⁄6⁄18 68 0.03 1.945 10.3 0.32 -5.078 Turbidity (NTU) 3⁄7⁄12-5⁄6⁄18 68 0.22 3.13 920 0.24 5.763 E. coli (cfu ⁄ 100mL) 3⁄7⁄12-5⁄6⁄18 68 0.5 4 1200 0.06 17.555 NH4-N (mg/l) 3⁄7⁄12-5⁄6⁄18 71 0.005 0.005 0.028 0.86 0 SS (mg/l) 3⁄7⁄12-5⁄6⁄18 70 1.5 1.5 1270 0.15 0

Ngaruroro Rv D/S HB Dairies

TN (mg⁄l) 3⁄7⁄12-5⁄6⁄18 70 0.055 0.13 2.5 0.32 0.849 TP (mg⁄l) 3⁄7⁄12-5⁄6⁄18 71 0.002 0.009 0.85 0.05 10.883 DIN (mg/l) 3⁄7⁄12-5⁄6⁄18 66 0.027 0.086 0.385 0.23 4.129 DRP (mg/l) 3⁄7⁄12-5⁄6⁄18 71 0.002 0.005 0.026 0.00 7.865 NO3-N (mg/l) 3⁄7⁄12-5⁄6⁄18 70 0.019 0.076 0.34 0.24 5.368 Black Disc 3⁄7⁄12-5⁄6⁄18 68 0.02 1.05 7.1 0.10 -9.628 Turbidity (NTU) 3⁄7⁄12-5⁄6⁄18 68 0.38 6.985 910 0.02 8.995 E. coli (cfu ⁄ 100mL) 3⁄7⁄12-5⁄6⁄18 68 0.5 11 2100 0.09 16.823 NH4-N (mg/l) 3⁄7⁄12-5⁄6⁄18 71 0.005 0.005 0.04 0.59 0 SS (mg/l) 3⁄7⁄12-5⁄6⁄18 71 1.5 6 1240 0.17 0

Ohiwia Strm TN (mg⁄l) 15⁄11⁄12-5⁄6⁄18 62 0.17 0.665 4.4 0.26 6.028 TP (mg⁄l) 15⁄11⁄12-5⁄6⁄18 62 0.057 0.123 0.8 0.28 3.683



Trend PAC

DIN (mg/l) 15⁄11⁄12-5⁄6⁄18 59 0.014 0.468 1.576 0.19 2.236 DRP (mg/l) 15⁄11⁄12-5⁄6⁄18 62 0.052 0.113 0.4 0.11 6.621 NO3-N (mg/l) 15⁄11⁄12-5⁄6⁄18 62 0.001 0.395 1.51 0.18 3.007 Black Disc 15⁄11⁄12-5⁄6⁄18 54 0.07 3.15 7.8 0.58 3.393 Turbidity (NTU) 15⁄11⁄12-2⁄5⁄18 54 0.28 1.2 190 0.58 -6.329 E. coli (cfu ⁄ 100mL) 10⁄1⁄13-5⁄6⁄18 60 3 100 21000 0.40 12.853 NH4-N (mg/l) 15⁄11⁄12-5⁄6⁄18 62 0.005 0.005 0.104 0.80 0 SS (mg/l) 15⁄11⁄12-5⁄6⁄18 61 1.5 1.5 300 0.00 0

Poporangi

TN (mg⁄l) 15⁄11⁄12-10⁄4⁄19 75 0.26 0.7 2.5 0.243 2.884 TP (mg⁄l) 15⁄11⁄12-10⁄4⁄19 75 0.008 0.032 0.64 0.063 3.469 DIN (mg⁄l) 15⁄11⁄12-10⁄4⁄19 70 0.13 0.531 1.077 0.723 0.99 DRP (mg⁄l) 15⁄11⁄12-10⁄4⁄19 75 0.009 0.026 0.045 0.09 2.425 NO3-N (mg/l) 15⁄11⁄12-10⁄4⁄19 75 0.118 0.53 1.07 0.773 0.787 Black Disc 4⁄12⁄12-10⁄4⁄19 64 0.02 1.625 8.9 0.949 -0.329 Turbidity (NTU) 4⁄12⁄12-7⁄3⁄19 63 0.84 2.68 934 0.194 8.168 E. coli (cfu ⁄ 100mL) 15⁄11⁄12-10⁄4⁄19 73 4 46 4000 0.174 7.335 NH4-N (mg/l) 15⁄11⁄12-10⁄4⁄19 75 0.003 0.003 0.019 0 0 SS (mg/l) 15⁄11⁄12-10⁄4⁄19 75 0.25 3 930 0.436 3.802

Poukawa Strm

TN (mg⁄l) 17⁄7⁄12-7⁄6⁄18 68 0.22 1.435 5.4 1.00 0.26 TP (mg⁄l) 17⁄7⁄12-7⁄6⁄18 67 0.04 0.172 0.6 0.01 8.136 DIN (mg/l) 17⁄7⁄12-7⁄6⁄18 65 0.014 0.117 3.58 0.10 -8.682 DRP (mg/l) 17⁄7⁄12-7⁄6⁄18 67 0.021 0.143 0.59 0.01 10.08 NO3-N (mg/l) 17⁄7⁄12-7⁄6⁄18 67 0.001 0.078 3.5 0.07 -2.579 Black Disc 17⁄7⁄12-7⁄6⁄18 42 0.34 1.88 3.6 0.12 12.561 Turbidity (NTU) 17⁄7⁄12-7⁄6⁄18 59 0.43 1.46 25.8 0.49 -3.106 E. coli (cfu ⁄ 100mL) 17⁄7⁄12-7⁄6⁄18 67 9 130 3100 0.06 8.004 NH4-N (mg/l) 17⁄7⁄12-7⁄6⁄18 68 0.005 0.005 0.135 0.01 0 SS (mg/l) 17⁄7⁄12-7⁄6⁄18 67 1.5 1.5 30 0.01 0

Raupare Drain

TN (mg⁄l) 26⁄11⁄13-7⁄6⁄18 53 0.14 0.41 8.5 0.00 11.419 TP (mg⁄l) 26⁄11⁄13-7⁄6⁄18 53 0.021 0.038 0.22 0.25 5.281 DIN (mg/l) 26⁄11⁄13-7⁄6⁄18 51 0.014 0.293 7.704 0.01 12.622 DRP (mg/l) 26⁄11⁄13-7⁄6⁄18 53 0.018 0.027 0.045 0.28 -3.468 NO3-N (mg/l) 26⁄11⁄13-7⁄6⁄18 53 0.001 0.26 7.6 0.02 11.908 Black Disc 26⁄11⁄13-7⁄6⁄18 42 0.1 1.86 4.32 0.18 9.078 Turbidity (NTU) 26⁄11⁄13-7⁄6⁄18 45 1.16 2.44 57.2 0.61 -4.224 E. coli (cfu ⁄ 100mL) 26⁄11⁄13-7⁄6⁄18 49 32 320 2700 0.15 14.487 NH4-N (mg/l) 26⁄11⁄13-7⁄6⁄18 53 0.005 0.016 0.093 0.16 0 SS (mg/l) 26⁄11⁄13-7⁄6⁄18 53 1.5 1.5 138 1.00 0

Taipo Strm

TN (mg⁄l) 17⁄7⁄12-7⁄6⁄18 63 0.27 0.94 10.57 0.16 5.725 TP (mg⁄l) 17⁄7⁄12-7⁄6⁄18 62 0.161 0.38 1.12 0.43 3.625 DIN (mg/l) 17⁄7⁄12-7⁄6⁄18 63 0.014 0.356 10.013 0.90 -0.188 DRP (mg/l) 17⁄7⁄12-7⁄6⁄18 62 0.094 0.25 1.08 0.59 1.542



Trend PAC

NO3-N (mg/l) 17⁄7⁄12-7⁄6⁄18 63 0.001 0.132 10 0.90 0 Black Disc 17⁄7⁄12-7⁄6⁄18 24 0.06 0.4 3.65 0.27 -24.06 Turbidity (NTU) 17⁄7⁄12-7⁄6⁄18 57 1.38 12 115 0.67 9.368 E. coli (cfu ⁄ 100mL) 17⁄7⁄12-7⁄6⁄18 60 2 1050 26000 0.06 9.789 NH4-N (mg/l) 17⁄7⁄12-7⁄6⁄18 63 0.005 0.082 0.502 0.38 0 SS (mg/l) 17⁄7⁄12-7⁄6⁄18 63 1.5 23 145 1.00 0

Tūtaekurī Rv by Brookfields

Br

TN (mg⁄l) 19⁄7⁄12-12⁄6⁄18 68 0.055 0.276 4.6 0.00 8.815 TP (mg⁄l) 19⁄7⁄12-12⁄6⁄18 68 0.002 0.026 1.62 0.09 5.223 DIN (mg/l) 19⁄7⁄12-12⁄6⁄18 66 0.014 0.168 0.609 0.35 0.302 DRP (mg/l) 19⁄7⁄12-12⁄6⁄18 68 0.002 0.02 0.062 0.11 4.969 NO3-N (mg/l) 19⁄7⁄12-12⁄6⁄18 68 0.001 0.157 0.6 0.34 0.846 Black Disc 19⁄7⁄12-12⁄6⁄18 65 0.02 2 8.1 0.67 3.353 Turbidity (NTU) 19⁄7⁄12-12⁄6⁄18 62 0.27 2.47 2500 1.00 2.225 E. coli (cfu ⁄ 100mL) 19⁄7⁄12-12⁄6⁄18 67 0.5 21 17000 0.22 10.19 NH4-N (mg/l) 19⁄7⁄12-12⁄6⁄18 68 0.005 0.005 0.063 0.25 0 SS (mg/l) 19⁄7⁄12-12⁄6⁄18 68 1.5 3 1950 0.75 0

Tūtaekurī Rv at Lawrence

Hut

TN (mg⁄l) 19⁄7⁄12-28⁄5⁄18 67 0.053 0.055 0.31 0.12 0 TP (mg⁄l) 19⁄7⁄12-28⁄5⁄18 68 0.002 0.005 0.053 0.16 5.014 DIN (mg/l) 19⁄7⁄12-28⁄5⁄18 66 0.014 0.016 0.075 0.02 -3.081 DRP (mg/l) 19⁄7⁄12-28⁄5⁄18 68 0.002 0.004 0.006 0.17 0 NO3-N (mg/l) 19⁄7⁄12-28⁄5⁄18 67 0.001 0.006 0.069 0.86 -0.828 Black Disc 19⁄7⁄12-28⁄5⁄18 66 0.12 7.25 14.2 0.16 -4.233 Turbidity (NTU) 19⁄7⁄12-28⁄5⁄18 67 0.16 0.78 48.9 0.68 2.098 E. coli (cfu ⁄ 100mL) 19⁄7⁄12-28⁄5⁄18 67 0.5 14 180 0.08 5.341 NH4-N (mg/l) 19⁄7⁄12-28⁄5⁄18 68 0.005 0.005 0.005 1.00 - SS (mg/l) 19⁄7⁄12-28⁄5⁄18 68 1.5 1.5 67 0.86 0

Tūtaekurī River U⁄S

Mangaone

TN (mg⁄l) 19⁄7⁄12-12⁄6⁄18 69 0.055 0.24 3.1 0.00 9.566 TP (mg⁄l) 19⁄7⁄12-12⁄6⁄18 69 0.002 0.017 0.59 0.06 5.694 DIN (mg/l) 19⁄7⁄12-12⁄6⁄18 67 0.014 0.159 0.486 0.29 0.62 DRP (mg/l) 19⁄7⁄12-12⁄6⁄18 69 0.002 0.014 0.036 0.05 4.042 NO3-N (mg/l) 19⁄7⁄12-12⁄6⁄18 69 0.001 0.163 0.48 0.07 2.132 Black Disc 19⁄7⁄12-12⁄6⁄18 63 0.02 2.3 6.1 0.53 -4.215 Turbidity (NTU) 19⁄7⁄12-28⁄5⁄18 64 0.4 2.58 241 0.53 3.27 E. coli (cfu ⁄ 100mL) 19⁄7⁄12-12⁄6⁄18 68 0.5 16 6200 0.03 18.485 NH4-N (mg/l) 19⁄7⁄12-12⁄6⁄18 69 0.005 0.005 0.077 0.74 0 SS (mg/l) 19⁄7⁄12-12⁄6⁄18 69 1.5 1.5 1130 0.55 0

Tūtaekurī -Waimate Strm

TN (mg⁄l) 3⁄7⁄12-5⁄6⁄18 71 0.055 0.372 5.5 0.34 3.283 TP (mg⁄l) 3⁄7⁄12-5⁄6⁄18 71 0.025 0.04 0.134 0.54 1.872 DIN (mg/l) 3⁄7⁄12-5⁄6⁄18 67 0.014 0.243 4.513 1.00 0 DRP (mg/l) 3⁄7⁄12-5⁄6⁄18 71 0.021 0.031 0.074 0.66 1.071 NO3-N (mg/l) 3⁄7⁄12-5⁄6⁄18 71 0.001 0.22 4.3 0.83 0.513 Black Disc 3⁄7⁄12-8⁄3⁄18 45 0.44 1.55 3.6 0.62 5.465



Trend PAC

Turbidity (NTU) 3⁄7⁄12-2⁄5⁄18 61 0.83 3.42 14.1 1.00 -2.044 E. coli (cfu ⁄ 100mL) 3⁄7⁄12-5⁄6⁄18 68 5 75 4400 0.60 -5.009 NH4-N (mg/l) 3⁄7⁄12-5⁄6⁄18 71 0.005 0.005 0.118 0.25 0 SS (mg/l) 3⁄7⁄12-5⁄6⁄18 71 1.5 4.6 31 0.39 0

Waitio Strm

TN (mg⁄l) 3⁄7⁄12-5⁄6⁄18 71 0.18 0.3 1.701 0.27 2.214 TP (mg⁄l) 3⁄7⁄12-5⁄6⁄18 68 0.014 0.03 0.39 0.56 -2.155 DIN (mg/l) 3⁄7⁄12-5⁄6⁄18 68 0.112 0.212 0.782 0.13 4.12 DRP (mg/l) 3⁄7⁄12-5⁄6⁄18 69 0.011 0.023 0.29 0.91 0.325 NO3-N (mg/l) 3⁄7⁄12-5⁄6⁄18 71 0.095 0.21 0.77 0.23 4.756 Black Disc 3⁄7⁄12-5⁄6⁄18 63 0.1 4 8.1 0.02 9.985 Turbidity (NTU) 3⁄7⁄12-5⁄6⁄18 66 0.35 1.23 77.3 0.28 -6.021 E. coli (cfu ⁄ 100mL) 3⁄7⁄12-5⁄6⁄18 67 3 30 12000 0.86 0 NH4-N (mg/l) 3⁄7⁄12-5⁄6⁄18 71 0.005 0.005 0.085 0.34 0 SS (mg/l) 3⁄7⁄12-5⁄6⁄18 71 1.5 1.5 98 0.64 0


Appendix D Regional ranking tables for select water quality variables Tables in the following pages are coloured and coded in line with the major regional water management zones identified below. Letters relate to:

o (A) Porangahau River/Southern Coastal o (B) Tukituki River o (C) TANK (Tūtaekurī River, Ahuriri Estuary, Ngaruroro River, Karamū Stream) o (D) Mohaka River (bordered in black) o (E) Waikari River/Esk River/Aropaoanui River o (F) Wairoa River/Northern Coastal


Sites ranked by median Total Nitrogen (TN, mg/L), 2013-2018, with colours signifying reporting zone. Lower ranks are ‘better’. Medians generated from sample sizes of at least 30 are considered robust (Snelder pers. comm. 2014). Medians generated from sample sizes less than 30 should be treated with caution.


Sites ranked by median Total Phosphorus (TP, mg/L), 2013-2018, with colours signifying reporting zone. Lower ranks are ‘better’. Medians generated from sample sizes of at least 30 are considered robust (Snelder pers. comm. 2014). Medians generated from sample sizes less than 30 should be treated with caution.


Sites ranked by median Dissolved Inorganic Nitrogen (DIN, mg/L), 2013-2018, with colours signifying reporting zone. Lower ranks are ‘better’. Medians generated from sample sizes of at least 30 are considered robust (Snelder pers. comm. 2014). Medians generated from sample sizes less than 30 should be treated with caution.


Sites ranked by median Dissolved Reactive Phosphorus (DRP, mg/L), 2013-2018, with colours signifying reporting zone. Lower ranks are ‘better’. Medians generated from sample sizes of at least 30 are considered robust (Snelder pers. comm. 2014). Medians generated from sample sizes less than 30 should be treated with caution.


Sites ranked by median Nitrate-Nitrogen (NO3-N, mg/L), 2013-2018, with colours signifying reporting zone. Lower ranks are ‘better’. Medians generated from sample sizes of at least 30 are considered robust (Snelder pers. comm. 2014). Medians generated from sample sizes less than 30 should be treated with caution.


Sites ranked by median Black Disc (m), 2013-2018, with colours signifying reporting zone. Lower ranks are ‘better’. Medians generated from sample sizes of at least 30 are considered robust (Snelder pers. comm. 2014). Medians generated from sample sizes less than 30 should be treated with caution.


Sites ranked by median Turbidity (NTU), 2013-2018, with colours signifying reporting zone. Lower ranks are ‘better’. Medians generated from sample sizes of at least 30 are considered robust (Snelder pers. comm. 2014). Medians generated from sample sizes less than 30 should be treated with caution.


Sites ranked by median E. coli (CFU/100ml), 2013-2018, with colours signifying reporting zone. Lower ranks are ‘better’. Medians generated from sample sizes of at least 30 are considered robust (Snelder pers. comm. 2014). Medians generated from sample sizes less than 30 should be treated with caution.


Sites ranked by median Macroinvertebrate Community Index (MCI), 2013-2018, with colours signifying reporting zone. Lower ranks are ‘better’. Medians generated from sample sizes of at least 30 are considered robust (Snelder pers. comm. 2014). Medians generated from sample sizes less than 30 should be treated with caution.


Sites ranked by median Total Suspended Solids (TSS, mg/L), 2013-2018, with colours signifying reporting zone. Lower ranks are ‘better’. Medians generated from sample sizes of at least 30 are considered robust (Snelder pers. comm. 2014). Medians generated from sample sizes less than 30 should be treated with caution.


Appendix E NPS-FW (2014) NOF attribute tables

Nitrate NOF attribute table


Ammonia NOF attribute table


Escherichia coli NOF attribute table


Appendix F Summary of NOF bands for E.coli, Nitrate-nitrogen and Ammonia-nitrogen.

NPS-FM (2014) NOF bands for the nitrate-nitrogen toxicity attribute for Ngaruroro and Tūtaekurī catchment monitoring sites. . Cells are coloured as per the attribute state grading shown.

A B C D

2014 2015 2016 2017 2018 2014 2015 2016 2017 2018Ngaruroro Rv at Kuripapango (NIWA) NA NA NA NA NA NA NA NA NA NANgaruroro Rv at Whanawhana 0.017 0.015 0.008 0.02 0.044 0.106 0.061 0.037 0.92 0.227Ohara Strm NA 0.012 0.033 0.072 0.161 NA 0.016 0.147 0.455 0.449Poporangi Strm NA NA NA NA NA NA NA NA NA NANgaruroro Rv D/S HB Dairies 0.134 0.046 0.051 0.072 0.134 0.26 0.076 0.117 0.322 0.338Maraekakaho Strm 0.55 0.38 0.128 0.335 0.057 2.7 1.19 0.593 1.86 1.431Waitio Strem 0.24 0.179 0.145 0.23 0.27 0.54 0.344 0.307 0.744 0.762Ohiwa Strm 0.665 0.375 0.22 0.76 0.66 0.92 0.77 0.589 1.477 1.115Ngaruroro Rv at Fernhill 0.194 0.069 0.059 0.094 0.167 0.35 0.253 0.175 0.443 0.551Tutaekuri‐Waimate Strm 0.27 0.204 0.21 0.26 0.25 0.52 0.407 0.3 2.3 4.225Ngaruroro Rv at Chesterhope (NIWA) NA NA NA NA NA NA NA NA NA NATutaekuri Rv at Lawrence Hut 0.009 0.005 0.003 0.008 0.016 0.022 0.01 0.025 0.066 0.034Mangatutu Strm 0.4 0.32 0.315 0.5 0.51 0.851 0.66 0.857 0.728 0.848Tutaekuri Rv U/S Mangaone Rv 0.21 0.11 0.057 0.227 0.18 0.432 0.347 0.397 0.396 0.48Mangaone Rv at Rissington 0.345 0.315 0.203 0.425 0.34 0.767 0.6 0.728 0.774 0.89Tutaekuri Rv at Brookfields Br 0.21 0.059 0.009 0.305 0.25 0.539 0.42 0.458 0.536 0.598

Nitrate toxicity

SiteMedians 95th Percentiles


2014 2015 2016 2017 2018 2014 2015 2016 2017 2018Ngaruroro Rv at Kuripapango (NIWA) NA NA NA NA NA NA NA NA NA NANgaruroro Rv at Whanawhana 0.003 0.003 0.002 0.001 0.001 0.024 0.01 0.008 0.004 0.03Ohara Strm NA 0.001 0.003 0.002 0.001 NA 0.001 0.006 0.005 0.005Poporangi Strm NA NA NA NA NA NA NA NA NA NANgaruroro Rv D/S HB Dairies 0.002 0.004 0.002 0.001 0.001 0.009 0.017 0.018 0.002 0.049Maraekakaho Strm 0.007 0.003 0.002 0.003 0.006 0.014 0.017 0.017 0.015 0.019Waitio Strm 0.003 0.004 0.002 0.002 0.002 0.02 0.026 0.009 0.008 0.017Ohiwa Strm 0.019 0.006 0.005 0.004 0.008 0.035 0.017 0.034 0.018 0.066Ngaruroro Rv at Fernhill 0.004 0.002 0.004 0.001 0.003 0.043 0.018 0.036 0.009 0.046Tutaekuri‐Waimate Strm 0.016 0.008 0.008 0.015 0.003 0.026 0.018 0.028 0.045 0.029Ngaruroro Rv at Chesterhope (NIWA) NA NA NA NA NA NA NA NA NA NATutaekuri Rv at Lawrence Hut 0.002 0.003 0.003 0.001 0.001 0.006 0.005 0.008 0.003 0.006Mangatutu Strm 0.011 0.011 0.005 0.003 0.003 0.052 0.037 0.06 0.043 0.018Tutaekuri Rv U/S Mangaone Rv 0.007 0.007 0.007 0.002 0.002 0.777 0.025 0.016 0.012 0.017Mangaone Rv at Rissington 0.011 0.01 0.006 0.006 0.005 0.302 0.037 0.043 0.032 0.026Tutaekuri Rv at Brookfields Br 0.029 0.012 0.012 0.005 0.005 0.039 0.027 0.022 0.016 0.024

Ammonium toxicity

SiteMedians Maxima


NPS-FM (2014) NOF bands (5-yearly) for E. coli (swimmability) showing all four assessments. Cells are coloured as per the attribute state grading shown (‘A’ - ‘E’).

Band A B C D E

E. coli swimmability attribute

Site Samples 5 Year Median

Percent above

260

Percent above

540

95th Percentile

Overall Grade

Ngaruroro River at Whanawhana 59 4 3 2 111 A Ngaruroro River D/S Hawkes Bay Dairies 59 10 5 3 337 A Maraekakaho Stream at Maraekakaho 56 69 14 7 1400 D Waitio Stream at Ohiti Road 57 29 5 5 432 B Ohiwia Stream at Broughtons Br. 57 90 19 9 5215 D Ngaruroro River at Fernhill 58 40 9 5 740 B Tutaekuri Waimate Stm at Chesterhope 59 70 10 8 1265 D Tutaekuri River at Lawrence Hut 58 14 0 0 70 A Mangatutu Stream at Mangatutu Stn Br 59 45 14 14 4500 D Mangaone River at Rissington 57 50 12 11 1330 D

E. coli swimmability attribute

Site Samples 5 Year Median

Percent above

260

Percent above

540

95th Percentile

Overall Grade

Karewarewa Stream at Paki Paki 59 280 58 20 2640 E Awanui Stream at Flume 56 245 48 32 2560 E Poukawa Stream at Stock Road 59 130 24 7 700 B Herehere Stream at Te Aute Road 56 600 77 52 12880 E Raupare Drain at Ormond Road 52 320 67 27 1480 E Clive River U/S Whakatu Rail Bridge 58 230 40 19 7540 D Taipo Stream at Church Road 52 1250 73 67 4980 E

ngaruroro, tūtaekurī, karamū river and ahuriri estuary catchments · 2020-03-09 · n) levels at...

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