introduction - grand river conservation authority...river, water quality in the grand river...

Water Management Plan: TECHNICAL MEMORANDUM

1 | P a g e

Report No.: WMPSC-2010-12-01 Date: December 7, 2010

To: Grand River Water Management Plan Steering Committee

From: S. Cooke, GRCA

Subject: Summary of Watershed Trends in Water Quality: 2003 - 2008

REPORT:

Introduction

Water quality is described according to abiotic (e.g. chemical and physical attributes) and biotic (e.g.

organisms, communities) characteristics of freshwaters. To determine ‘state’ or ‘condition’, information

from routine monitoring, specific assessments/studies and research projects is synthesized and

presented to understand both spatial and temporal trends throughout the watershed. In the Grand

River watershed, data from the Provincial Water Quality Monitoring Program, the Grand River

Conservation Authority’s continuous monitoring network, as well as specific studies and research

projects were referenced and summarized to provide an overview of the state of the Grand River from

2003 to 2008. This report is based on a more detailed draft technical report by Loomer and Cooke (draft

2010). The technical report highlights information gaps and makes a number of recommendations to

improve the routine monitoring networks.

The primary focus of this overview is on abiotic factors - chemical and physical attributes of freshwaters;

however, biotic factors are referenced in the context of specific studies, research projects and general

assessment of specific ecologically significant areas in the watershed as there are no routine monitoring

programs for benthos or fish. For example, the biological state of the headwaters is described in a PhD

thesis (Yates, 2008), ecological integrity of fisheries in the Central Grand River region is described in two

recent Master’s theses (Loomer, 2008; Brown, 2010) and other ecologically significant areas of interest

are described by stakeholder groups working collaboratively toward evaluating specific reaches and/or

areas (e.g. Exceptional Waters, Tailwater Fisheries, southern Grand River walleye reserve). Information

gaps are highlighted and a series of recommendations are made.

The general state of water quality has historically been assessed by selecting key indicator parameters of

water quality. An indicator parameter is a specific attribute such as phosphorus or dissolved oxygen

that is deemed important in the complex interactions that occur within freshwater systems. For

example, phosphorus is generally the key limiting nutrient for freshwater aquatic plant growth, and as

such, is typically used to measure the degree of eutrophication (i.e. nutrient enrichment). Typically,

these indicators are used to describe key issues and/or use impairments in the watershed. Issues are

usually described in the context of an impaired use such as drinking water supplies, aquatic life,

assimilating wastewater discharges, or recreation to list a few. Given the multiple uses of the Grand

River, water quality in the Grand River watershed can best be described by using indicator parameters

that describe the most sensitive use. This, in most cases, is the use of the freshwater by aquatic life.


2 | P a g e

Indicator parameters are usually compared to thresholds or objectives that have been set to describe a

desired state. For example, dissolved oxygen levels below 4.0 mg/L do not provide for suitable

conditions that would support a healthy and diverse warmwater fish community.

Key indicator parameters in the Grand River watershed typically describe the complex processes of

eutrophication – the nutrient (nitrogen and phosphorus) enrichment of freshwaters that facilitates

increased aquatic plant growth that then impacts dissolved oxygen levels. Dissolved oxygen levels are a

crucial element required to support aquatic life. Figure 1 describes the generalized nutrient and

dissolved oxygen processes in the central Grand River region. Other indicator parameters are likely

more relevant in other river reaches. For example, total suspended solids and total phosphorus are

likely indicators of interest in the Nith and southern Grand River region while, temperature is likely a key

indicator parameter in the tailwater regions.

Figure 1. Conceptual diagram of the nutrient and dissolved oxygen processes in the central Grand River.

The state of the Grand River will be described by evaluating four key watershed regions: Grand River-

Lake Erie; Headwaters; Central Grand River; and Lower Grand River. The state of the river will be

described according to chemical or physical indicator parameters that are important to each specific

watershed region. Where possible, additional information on the biotic aspects of these particular

regions will be incorporated to understand the overall state of the river.

Grand River & Lake Erie

A key indicator parameter of importance to Lake Erie has historically been, and continues to be, total

phosphorus as it has been demonstrated as the limiting nutrient to the growth of pelagic (e.g. most

cyanobacteria) and benthic (e.g. Cladophora) algae (LENSTG, 2009). Recently, soluble reactive

phosphorus (SRP) - a estimated measure of biologically available phosphorus, is being debated as a

more relevant indicator parameter as it best describes the biological availability of the nutrient to

aquatic systems; however, scientists are debating the use of SRP as a more-widely used indicator as its

analytical measurement requires specific methods/handling times that may not be achievable in

current/existing monitoring programs. Currently, the Lake-wide Management Program is endorsing a

Nutrient Management Strategy that promotes the adoption of best practices throughout the Lake Erie


3 | P a g e

basin to reduce the overall loading of phosphorus (LELaMP 2010). Consequently, the concentrations

and loads of total phosphorus remain the indicator parameters at the mouth of the Grand River as it

helps to describe the river’s influence on Lake Erie.

Concentrations in the river at Dunnville almost always exceed the Provincial Water Quality Objective

(PWQO) of 0.03 mg/L with maximum concentrations occurring during the spring (April) and approaching

10 times the objective (Figure 2). The levels of total phosphorus being discharged into Lake Erie,

specifically during the active summer growing season, are significant locally and are thought to be a

driving factor behind the abundant Cladophora growth observed along the nearshore area (Howell,

2003).

The total annual load of total phosphorus from the Grand River to the eastern basin of Lake Erie was

estimated to be about 402 metric tonnes per year (MTA) in 2004 (D. Dolan, unpublished data). Although

it represents about four percent of the total loads to Lake Erie, the Grand River contributes about 40

percent of the total load to the eastern basin (Figure 3). The Grand River is the largest contributor of

phosphorus to the eastern Basin of Lake Erie; however, relative to all tributaries, it ranks 5th largest

among 30 US and Canadian tributaries.

Figure 2. Total phosphorus concentrations in the Grand River at Dunnville, 2003 - 2008. Data from the Ministry of the Environment's Provincial Water Quality Monitoring Network. LaMP tributary target for total phosphorus is 0.032 ug/L.


4 | P a g e

Figure 3. Total phosphorus loads to the eastern basin of Lake Erie (2004). The Grand River contributed approximately 398 metric tonnes per year (MTA). Data from David Dolan, University of Wisconsin, Green Bay.

Total phosphorus levels in the Grand River at Dunnville are reflective of the cumulative contributions

from the entire upstream watershed. Given the importance of total phosphorus to Lake Erie, total

phosphorus remains one of the key indicator parameters throughout the Grand River watershed.

Headwaters

The headwater region of the Grand River watershed encompasses the upper Grand, Conestogo, Nith

and Speed/Eramosa rivers. With the exception of the Nith and Eramosa rivers, these areas drain to

man-made, multi-purpose reservoirs. These reservoirs are operated for flood protection and low-flow

augmentation; yet they also provide local recreational opportunities. Although the upper Speed and

Eramosa rivers drain a physiographically unique region - the Guelph drumlin fields, the other rivers drain

similar physiographic features – till plains (e.g. Dundalk, Stratford, Tavistock) that are characterized by

high surface runoff and low soil infiltration. The upper Conestogo and Nith also have similar land cover

and land management practices as intensive agricultural production predominates while the upper

Grand, Speed and Eramosa river regions have notably greater wetland and forested areas. There are

few point source discharges servicing small, but growing communities, that generally discharge

seasonally. Streams and rivers in these areas are characterized as generally warm-water habitats which

are dominated by spring runoff; however; there are exceptions in the upper Grand (e.g. Butler Creek),

upper Speed (e.g. Lutteral Creek) and Eramosa River regions (e.g. Blue Springs creek) in which water

temperatures are mixed or even cold-water.

Given the importance of total phosphorus as a key limiting nutrient to aquatic plants and algae in

freshwater systems, and its importance to productivity in Lake Erie, it is important to understand the


5 | P a g e

total phosphorus levels throughout the watershed. In the headwater region, total phosphorus levels are

high, generally exceeding the provincial objective of 0.03 mg/L in the upper Nith, Conestogo and

Canagagigue Creeks (Figure 4). On the other hand, total phosphorus levels tend to be at or below the

PWQO in the upper Grand and upper Speed/Eramosa river watersheds.

Figure 4. Box and whisker plots showing the range of total phosphorus concentrations (mg/L) at sites located in the headwater region: upper Nith, Conestogo, Grand and Speed rivers.

Reservoir water quality reflects both the inputs (e.g. runoff collected from the upper watershed areas)

and internal nutrient cycling (e.g. release of phosphorus from the reservoir sediments). All of the

reservoirs are classified as eutrophic as phosphorus levels are high enough to support substantial algae

and cyanobacteria growth, particularly during the late summer/early fall when the lakes turn over and

release high levels of phosphorus from the bottom waters (Figure 5 (a) and (f)).

Figure 5. Monthly total phosphorus levels (ug/L) in the epilimnion (a) and hypolimnion (f) of Belwood (open circles), Conestogo (x) and Guelph (triangle) reservoirs. Data from Guildford (2006).

These reservoirs are important both as a sink of nutrients from the headwater regions as well as a source of nutrients downstream when the reservoirs are discharged to augment river flows during the


6 | P a g e

summer months. Consequently, the quality of these reservoirs and the rivers that drain to them become very important to downstream communities.

Central Grand River region

The Grand River flows through the central region from the Shand Dam to Brantford. It collects surface

water from three major tributaries: the Conestogo; the Speed; and the Nith River, as well as many

minor tributaries including the Irvine Creek, Canagagigue Creek, Laurel Creek, Schneiders Creek and Mill

Creek. In addition to surface water, groundwater is also discharged directly to the central Grand River

and into many smaller tributaries draining the Waterloo and Paris-Galt moraines.

Flows in the central Grand River are sustained by the discharge from Belwood Reservoir combined with

flows from the major tributaries including the Conestogo, Speed, and Nith Rivers. The Canagagigue

Creek and Irvine Creek also contribute to the flows in the Grand River, though their annualized

contributions are relatively minor compared to the other major tributaries. The discharge of the Shand

dam to the Grand River presents the opportunity for a thriving coldwater tailwater fishery for brown

trout – an introduced species.

Water quality is reflective of both the geology and land use in this sub-basin. Agricultural production

tends to be much more intense throughout this region while most of the urban land use is focused in

this region as well. Furthermore, the complex geology, such as the moraines, has a significant influence

on the general water quality of the river in specific reaches as many of the small tributaries in the

central Grand River region are cold water, a direct result of the groundwater discharge. Water quality

in the cold water creeks tend to have lower phosphorus levels but tend to have high nitrate levels (e.g.

Alder Creek).

Generally, levels of total phosphorus and total nitrates progressively increase as the Grand River flows

from the Shand Dam to Brantford (Figure 6 and Figure 7). Although non-point sources are largely

driving elevated nutrient levels seen in the Grand River above Bridgeport, especially during the spring,

point sources become a significant contributor of phosphorus and ammonia-nitrogen during the

summer. Of note, however, are the observed high nitrate concentrations in the Grand River upstream

of Bridgeport, especially in the winter months (Figure 8). Groundwater may have an important role in

the elevated nitrate concentrations seen in the upper central Grand River area.


7 | P a g e

Figure 6. Box and whisker plots showing the range of total phosphorus concentrations (mg/L) along the Grand River and the mouth of major tributaries from the Shand Dam to Paris (2003 -2008).


8 | P a g e

Figure 7. Box and whisker plots showing the range of total nitrate concentrations (mg/L) along the Grand River and the mouth of major tributaries from the Shand Dam to Paris (2003 -2008).

Figure 8. Total nitrate concentrations (mg/L), by month, in the Grand River at Bridgeport.

Chloride concentrations reflect the influence of urban point and non-point sources but levels in the

Grand River do not exceed the water quality benchmark of 150 mg/L (Figure 9). Levels in the smaller


9 | P a g e

urban tributaries such as Schneider’s Creek and Laurel Creek are routinely above the benchmark,

primarily due to the use of road salt.

Given the numerous point source discharges to the Grand River through the central Grand River, and

significant aquatic plant and algae growth through this region, dissolved oxygen in the river is a concern.

Although dissolved oxygen tends to be above the provincial objective of 4.0 mg/L in the Grand River at

Bridgeport, it tends to drop below the objective frequently in the Grand River at Blair (Figure 10).

Dissolved oxygen levels tend to recover and, for the most part, remain above the provincial objective at

Glen Morris which is likely due to the significant groundwater being discharged into the Grand River

below Galt.

Figure 9. Box and whisker plots showing the range of chloride concentrations (mg/L) along the Grand River and the mouth of major tributaries from the Shand Dam to Paris (2003 -2008).


10 | P a g e

Figure 10. Minimum daily dissolved oxygen (mg/L) in the Grand River at Blair, in the central Grand River region, 2003-2008. Data from GRCA Continuous Monitoring Network.

The water quality at the mouths of the Conestogo, Irvine and Canagagigue Creeks is highly variable

across seasons. Higher total phosphorus concentrations during spring runoff are obvious and are

characteristic of the strong influence of non-point sources such as runoff from rural land use activities.

Nitrate concentrations in the Canagagigue Creek and Conestogo and Irvine rivers tend to be 2 to 3 times

higher than those found in the Grand River suggesting that these areas contribute substantially to the

overall nitrate load to the Grand River above Bridgeport.

The Canagagigue Creek drains some of the most intensive agricultural lands in the watershed. Nutrient

levels in the Canagagigue Creek are among the highest in the watershed. The Woolwich reservoir, built

to protect the town of Elmira from flooding and to ensure flows during the summer, is highly eutrophic.

This is a result of the extremely high levels of both total phosphorus and nitrate in the creek that flows

into the reservoir. Canagagigue Creek below the town of Elmira is influenced by the wastewater

treatment plant discharge as is evident by the three-fold increase in chloride levels when compared to

upstream concentrations.

As the Grand River flows through the urban area of the central region, it accumulates both non-point

urban runoff and numerous point source discharges. The Speed River flows into the Grand in Cambridge

and, although the Speed River is a large tributary, it does not contribute significantly to the phosphorus

levels already in the Grand River. However, the Speed River does appear to contribute substantially to

the overall chloride levels found in the Grand River below the urban area at Glen Morris.

The Nith River drains mostly rural lands with very intensive agricultural production. Phosphorus levels

tend to be high and variable, especially during the spring. Nitrate levels at the mouth of the Nith River

are also high as the lower Nith River tends to be heavily influenced by groundwater discharges, which

are likely high in nitrate, from the Waterloo and Paris-Galt moraines. Chloride levels are generally low

and do not contribute substantially to the levels found in the Grand River at Brantford.

At the southern end of the central Grand River region is an area referred to as the Exceptional Waters

reach. The area of the Grand River between Paris and Brantford brings together biological, chemical


11 | P a g e

and physical attributes that allows for a thriving warm-water fish community yet seasonally, it can

support cold water and migratory fish. Cold water entering the river from upstream groundwater

discharges in the Grand and Nith rivers, as well as Whiteman's Creek, a cold water creek, plus the

characteristics of the river itself, make it a good habitat for a wide range of species including smallmouth

bass, walleye, northern pike and a unique resident population of rainbow trout. It is also home to

several fish species at risk, such as the black redhorse and river redhorse which are found in few

locations in Canada.

Lower Grand River Region

As the Grand River flows through Brantford toward York, Dunnville and Lake Erie, it becomes a large

seventh order river which flows through the Haldimand Clay plain. Consequently, the quality of the

lower Grand River sub-basin is reflective of the cumulative influence of numerous point source

discharges and runoff from both urban and rural land uses which are mostly located in the central Grand

River region. This is reflected in the very high phosphorus levels seen in the Grand River throughout the

lower reach from Brantford to Dunnville (Figure 11). However, the influence of the local geology in this

region is readily apparent as the river becomes more turbid, carrying a lot of suspended sediments and

clay particles, once it flows over the clay plain.

The effects of dams on the lower Grand River are evident. The river’s flow is slowed down and water

tends to be impounded behind both the Caledonia and Dunnville dams. Total phosphorus levels tend to

be elevated above the dams which suggests a build up of fine sediments and low oxygen conditions that

promote the cycling of phosphorus (Figure 12) (Cooke 2003). Furthermore, the impounded nature of

the lower Grand River causes the river to be lake-like and experiences similar nutrient processing

mechanisms that affect eutrophic lakes. Dissolved oxygen profiles of the river between Cayuga and

Dunnville show periods of anoxia (T. MacDougall, MNR) (Figure 13) and an assessment of the benthic

invertebrates downstream of Cayuga in 2003-2005 is dominated by species which are pollution tolerant

and thrive in low oxygen environments (MacDougall et al 2008).

The unique southern Grand River stock of walleye, which moves between the lake (summer foraging)

and river (spring spawning), serves an important role in the ecosystem (top predator) and fisheries

(commercial and sport) of both Lake Erie and the lower Grand River as it can survive in highly turbid, low

light conditions. The lower Grand River, characterized by highly turbid water, presents itself as a

particularly important area for walleye; however, restricted access to the river above Dunnville limits

the success of this species (MacDougall et al 2008).

Overall, high total phosphorus levels, periodic low dissolved oxygen levels and a pollution-tolerant

benthic invertebrate community combine to describe generally poor conditions in the lower Grand River

region.


12 | P a g e

Figure 11. Box and whisker plots showing the range of total phosphorus concentrations (mg/L) along the Grand River and the mouth of major tributaries from Brantford to Dunnville, near the mouth of the Grand River (2003 -2008).

Figure 12. Average total phosphorus levels (mg/L) (top) at sampling sites along the lower Grand River between Brantford and Dunnville. Total phosphorus levels appear to be influeced by the dams along the reach. Grand River


13 | P a g e

elevation profile (bottom) between Brantford and Dunnville illustrates the gentle slopes and lake-like character of the river.

Figure 13. Dissolved oxygen (mg/L) profiles at select locations between Cayuga and Dunnville in the lower Grand River in July 2005. Note periods of very low oxygen near the river bottom. Data from T. MacDougall, MNR.

References Brown, C.J.M. 2010. Fish communities near municipal wastewater discharges in the Grand River watershed. M.Sc. thesis, University of Waterloo. Cooke, S. 2004. Southern Grand River Rehabilitation Initiative: Water Quality Characterization. Grand River Conservation Authority, Cambridge, ON. 49p. Dolan, David. University of Wisconsin, Green Bay. Guildford, S. 2006. Factors controlling Cyanobacteria blooms in three Grand River Basin reservoirs during 2005. University of Waterloo, Waterloo, ON. 16p. Howell, T., A. Todd. 2003 Impacts of tributaries on nearshore eastern Lake Erie. Presentation to the

International Association of Great Lakes Research.

Lake Erie Nutrient Science Task Group. 2008. Status of Nutrients in the Lake Erie Basin. Lake Erie Lake-wide Management Plan. Lake Erie Lake-wide Management Plan. 2010. Lake Erie Binational Nutrient Management Strategy. Loomer, H.A. 2008. The dynamics of carbon and nitrogen stable isotope signatures of aquatic food webs in the Grand River watershed. M.Sc. thesis. University of Waterloo.


14 | P a g e

MacDougall, T. et al. 2008. Southern Grand River: State of the River Summary Report. Ministry of Natural Resources, Port Dover, ON. 39p. Yates, A.G. 2008. Development, testing and application of stressor gradients in rural, headwater streams in Southwestern Ontario. Ph.D. thesis, University of Western Ontario.

Prepared by: Approved by: __________________________________ __________________________________ Sandra Cooke Lorrie Minshall Senior Water Quality Supervisor Water Management Plan Director

introduction - grand river conservation authority...river, water quality in the grand river...

Documents