draft 2016 water inventory and analysis report · •april– pac review of initial draft wi&a...

Draft 2016Water Inventory and

Analysis Report

Prepared by

Davids Engineering, Inc.

June 1, 2016

June 1, 2016DRAFT Water Inventory and Analysis Report 1

Overview of Presentation

• Background and Analytical Approach

• Relationship to Sustainable Groundwater Management Act of 2014

• Inventory and Analysis Update Process, Timeline, and Document Structure

• Results• Conclusions and

Recommendations


2016 Draft Report

Background

• Update to 2001 Water Inventory and Analysis Report (WI&A)• Initiated in 2013• Accounting of Supplies

and Demands for 2000 to 2014• Substantial Updates to

Analytical Approach


2001 Report


Analytical Approach• Integration of Butte

Basin Groundwater Model (BBGM) to Develop Land Surface Water Budgets• Refinements to

BBGM inputs to better represent historical hydrologic conditions

• Development of multi-year water budgets (vs. typical year types)• Development of

potential demand and climate change scenarios for future analysis


Analytical Approach

Note on Uncertainty

• Updates to the BBGM and WI&A rely on the best available information• All data and estimates are subject to

uncertainty• Trends and differences are more reliable

than absolute numbers


Relationship to SGMA

• Sustainable Groundwater Management Act (SGMA)• Calls for establishment of Groundwater

Sustainability Agencies (GSAs)• Requires Groundwater Sustainability Plans

(GSPs) as defined by State regulations• Water budgets provide foundation to meet

GSP requirements• Potential demand and climate change

scenarios also support GSP development


WI&A Update Process

• Led by Department of Water and Resource Conservation staff• Technical support by Davids Engineering and

West-Yost Associates• Periodic review and input from Project

Advisory Committee (PAC) and Water Commission• Periodic updates:

• Public information sheets and Department newsletters• Water Advisory Committee meetings• Technical Advisory Committee meetings


Project Advisory Committee (PAC)

• Paul Gosselin and Vickie Newlin –Department of Water and Resource Conservation• Dan Breedon – Department of Development

Services• George Barber and David Skinner – Water

Commission• Joe Connell, Pete Bonacich, and Richard

Price – Technical Advisory Committee


WI&A Update Timeline

• 2013• 2 PAC meetings

• 1 Water Commission meeting

• 2014• Public information sheet

• Preparation of Feather River Regional Agricultural

Water Management Plan (FRRAWMP) and initial BBGM

datasets


WI&A Update Timeline (continued)

• 2015• Further development of BBGM input datasets and surface layer

water budget calibration

• Update FRRAWMP

• 2 PAC meetings

• 2016• February – Water Commission presentation on drought impacts

• April– PAC review of initial draft WI&A report update

• June 1 (Today) – Water Commission presentation on 2016 WI&A

• June 14 – Public workshop

• June 30 – Finalize 2016 WI&A


2016 WI&A Structure

Executive Summary1. Introduction2. Inventory and Analysis Methodology3. Land Use and Cropping Patterns4. Climate and Hydrology

• Climate• Surface Water Hydrology • Groundwater Hydrology


2016 WI&A Structure (continued)

5. Historical Water Demands and Supplies6. Future Water Demands and Supplies7. Conclusions and Recommendations8. References


2016 WI&A Structure (continued)

APPENDICES:A. Water Suppliers and ManagersB. Butte County Stream Gages and

Monitoring WellsC. Subinventory Unit Water BudgetsD. Assessment of Butte County Drought

Impacts, 2012-2015


2016 WI&A Results

• Land Use• Climate and Hydrology

• Precipitation• Surface water runoff and diversions• Groundwater conditions and pumping

• Water Budgets


Land Use


Land Use

• Land Use Data Sources• Department of Water Resources (DWR) land use

surveys• Agricultural Commissioner crop reports• Water supplier cropping records

• Valley Floor General Land Use• Irrigated Lands 234,000 acres• Non-Irrigated Lands 141,000 acres• Developed Lands 47,000 acres• Wetlands 30,000 acres• TOTAL 452,000 acres


DWR County-Wide Land Use

• Surveys from 1994, 1999, 2004, 2011

• Identifies land use, water source, and other attributes

• High spatial detail

• Annual changes estimated from ag. commissioner crop reports through 2014


262 240 233 240

741 740 734 704

23 28 31 3148 65 74 97

0

200

400

600

800

1000

1200

1994 1999 2004 2011

Acre

s (Th

ousa

nds)

Year

Irrigated Agriculture Non-Irrigated Wetlands Developed

County-Wide DWR General Land Use


236 234 234 235

148 144 141 137

26 29 30 3042 44 47 50

0

50

100

150

200

250

300

350

400

450

500

1995-1999 2000-2004 2005-2009 2010-2014

Acre

s (Th

ousa

nds)


Valley Floor General Land Use


105 101 106 101

85 89 94 97

30 29 20 1815 16 14 20

0

50

100

150

200

250

1995-1999 2000-2004 2005-2009 2010-2014

Acre

s (Th

ousa

nds)

Rice Orchards Other Cropland Idle Cropland

Valley Floor Irrigated Land Use


39 40 38 37

23 27 35 40

13 1311 109 99 10

0

20

40

60

80

100

120

1995-1999 2000-2004 2005-2009 2010-2014

Acre

s (Th

ousa

nds)

Almonds Walnuts Prunes Other Trees and Vines

Valley Floor Orchard Land Use


117

4 3

12

1413

11

78

43

0

5

10

15

20

25

30

35

1995-1999 2000-2004 2005-2009 2010-2014

Acre

s (Th

ousa

nds)

Grain Pasture and Alfalfa Field and Annual

Valley Floor Other Crop Land Use


Land Use Summary


• Land use relatively stable since 2000• County-wide, developed lands increased

between 2000 and 2014• Primarily in Foothill and Mountain areas, likely due to

change in DWR classification methodology• Some increase in valley floor

• Orchards have shifted from almonds and prunes to walnuts• Overall increase in orchards is offset by

decreases in other, non-rice crops

Land Use Summary


• Potential for expansion in the East Butte and North Yuba inventory units• Quantifying potential as part of demand scenario

development• Evaluate potential impacts as part of future analysis

• DWR preparing land use survey for 2015• Review results when available• Identify any recent expansion not identified by

available crop reports

Climate and Hydrology


Climate and Hydrology• Precipitation

• Surface Water Runoff and Diversions

• Groundwater Conditions and Pumping



Average Annual Precipitation

• Approx. 17 to 100 inches per year depending on location

• Influences irrigation requirements, surface water supply, groundwater recharge

Inter-Annual Precipitation


0

20

40

60

80

100

12019

8119

8219

8319

8419

8519

8619

8719

8819

8919

9019

9119

9219

9319

9419

9519

9619

9719

9819

9920

0020

0120

0220

0320

0420

0520

0620

0720

0820

0920

1020

1120

1220

1320

1420

15

Annu

al P

recip

itatio

n (in

ches

)Chico Univ. Farm Paradise

2000 – 2014 Update PeriodChico Univ. Farm Average: 26.5 inParadise Average: 52.1 in

Sacramento Valley Water Year Index


0

2

4

6

8

10

12

14

16

197119721973197419751976197719781979198019811982198319841985198619871988198919901991199219931994199519961997199819992000200120022003200420052006200720082009201020112012201320142015

Sacr

amen

to V

alle

y W

ater

Year

Inde

x

Water Year

Wet Above Normal Below Normal Dry Critical

Update Period

Only 5 Above Normal orWet years out of 15.

Surface Water Runoff


Surface Water Diversions by Source and Type


0

100,000

200,000

300,000

400,000

500,000

600,000

700,000

800,000

900,000

1,000,000

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014

Annu

al D

iver

sions

(af)

Water Year

Feather River Ag Butte Creek Ag Sacramento River Ag Other Ag Developed


Groundwater Elevations and Flow• Figure shows Spring 2012• Wells from unconfined to

uppermost semi-confined aquifer

• Generally southwesterly towards Sacramento River, with local variability

• Cone of depression near Durham

• Direction can vary from year to year.

• During drought, areas of groundwater depression exacerbated


Groundwater Elevation Change

• Figure shows Spring 2004-15 change

• Wells 100 to 450 feet deep from main pumping zone

• Greatest decline in Vinaand West Butte inventory units where groundwater demand is greatest

• Relatively stable groundwater conditions in southern portion of County

Valley Floor Groundwater Pumping


Wide range,depending largely

on year type.

Littlecorrelationwith time.

Climate and Hydrology Summary

• Annual precipitation and resulting runoff are highly variable• Surface water supplies are relatively steady

despite year-to-year differences in precipitation due to senior water rights and water supply agreements (settlement contracts) • Variability in precipitation is a driver of year

to year differences in groundwater pumping


Water Budgets


Water Budgets• Valley floor inventory units (and subinventory units)• Overall and by general land use

• Irrigated agriculture and wetlands• Developed lands• Non-irrigated lands

• Inflows – Outflows ± Change in Storage = 0


Land Surface

Precipitation Evapotranspiration

DeepPercolation

GroundwaterPumping

Surface Water

Deliveries

Runoff and Return Flow

Valley Floor Overall Water Budget


Precip-itation

914Applied Surface Water

715

Ground-water

Pumping411

Evapo-trans-

piration1,062Deep

Perc-olation

432

Runoff and

Return Flow546

Inflows Outflows

Average Annual Inflows and Outflows (thousands of acre-feet)

Precip-itation

504

Applied Surface Water

709

Ground-water

Pumping374 Evapo-

trans-piration

851Deep Perc-

olation283

Runoff and

Return Flow453

Inflows Outflows


Precip-itation

98


6

Ground-water

Pumping36

Evapo-trans-

piration58

Deep Perc-

olation28

Runoff and

Return Flow55

Inflows Outflows

Precip-itation

313

Evapo-trans-

piration153

Deep Perc-

olation121

Runoff and

Return Flow38

Inflows Outflows

Valley FloorAverage Annual Water Budgets

Total Inflow/ Outflow

2,038 taf

IrrigatedAg./Wetlands

(1,587 taf)

DevelopedLands

(140 taf)

Non-IrrigatedLands

(312 taf)



2000 – 2014 Annual Inflows and Outflows (thousands of acre-feet)

0 500 1,000 1,500 2,000 2,500 3,000

20…

20…

20…

20…

20…

20…

20…

20…

20…

20…

20…

20…

20…

20…

20…

Outflows (taf/year)

Evapotranspiration Deep Percolation Runoff and Return Flow

05001,0001,5002,0002,5003,000

2000 (AN)

2001 (D)

2002 (D)

2003 (AN)

2004 (BN)

2005 (AN)

2006 (W)

2007 (D)

2008 (C)

2009 (D)

2010 (BN)

2011 (W)

2012 (BN)

2013 (D)

2014 (C)

Inflows (taf/year)

Applied Surface Water Groundwater Pumping Precipitation



Average Annual Inflows and Outflows by Year Type(thousands of acre-feet)

Water Year

Inflows (taf) Outflows (taf)

Change in

Storage (taf)

Precipi-tation

Surface Water

Ground-water

Evapotrans-piration

Deep Percolation

Runoff and

Return Flow

Averages by Hydrologic Year TypeWet 1,295 715 346 1,043 591 726 2

Above Normal

1,069 705 372 1,049 493 613 14

Below Normal

908 721 412 1,033 433 572 -6

Dry 789 726 431 1,091 372 480 4Critical 624 691 479 1,070 328 388 -22

Precip-itation

504


709

Ground-water

Pumping374 Evapo-

trans-piration

851Deep Perc-

olation283

Runoff and

Return Flow453

Inflows Outflows


Precip-itation

98


6

Ground-water

Pumping36

Evapo-trans-

piration58

Deep Perc-

olation28

Runoff and

Return Flow55

Inflows Outflows

Precip-itation

313

Evapo-trans-

piration153

Deep Perc-

olation121

Runoff and

Return Flow38

Inflows Outflows

VinaAverage Annual Water Budgets

Total Inflow/ Outflow296 taf


(170 taf)

DevelopedLands

(48 taf)

Non-IrrigatedLands

(78 taf)

Precip-itation

74

Surface Water

8

Ground-water

Pumping88

Evapo-trans-

piration114

Deep Perco-lation

40

Runoff and

Return Flow17

Inflows Outflows

Precip-itation

28

Ground-water

Pumping20

Evapo-trans-

piration16

Deep Perco-lation

9

Runoff and

Return Flow24

Inflows Outflows

Precip-itation

78

Evapo-trans-

piration39

Deep Perco-lation

31

Runoff and

Return Flow

8

Inflows Outflows

Vina Overall Water Budget



Water Year


Change in

Storage (taf)

Precipi-tation

Surface Water

Ground-water

Evapotrans-piration

Deep Percolation

Runoff and

Return Flow

Averages by Hydrologic Year TypeWet 251 7 92 169 119 64 2

Above Normal

213 7 100 166 97 56 0

Below Normal

178 8 109 167 81 48 0

Dry 155 8 115 169 63 45 2Critical 127 8 122 172 55 30 -4

Precip-itation

504


709

Ground-water

Pumping374 Evapo-

trans-piration

851Deep Perc-

olation283

Runoff and

Return Flow453

Inflows Outflows


Precip-itation

98


6

Ground-water

Pumping36

Evapo-trans-

piration58

Deep Perc-

olation28

Runoff and

Return Flow55

Inflows Outflows

Precip-itation

313

Evapo-trans-

piration153

Deep Perc-

olation121

Runoff and

Return Flow38

Inflows Outflows

West ButteAverage Annual Water Budgets

Total Inflow/ Outflow 408 taf


(336 taf)

DevelopedLands

(29 taf)

Non-IrrigatedLands

(43 taf)Precip-itation

43

Evapo-trans-

piration22

Deep Perco-lation

16

Runoff and

Return Flow

5

Inflows Outflows

Precip-itation

19

Ground-water

Pumping10

Evapo-trans-

piration11

Deep Perco-lation

5

Runoff and

Return Flow12

Inflows Outflows

Precip-itation

126


94

Ground-water

Pumping116

Evapo-trans-

piration201

Deep Perco-lation

67

Runoff and

Return Flow68

Inflows Outflows

West Butte Overall Water Budget



Water Year


Change in

Storage (taf)

Precipi-tation

Surface Water

Ground-water

Evapotrans-piration

Deep Percolation

Runoff and

Return Flow

Averages by Hydrologic Year TypeWet 261 91 102 227 117 111 -1

Above Normal

222 96 113 230 103 99 2

Below Normal

185 97 126 232 89 87 -1

Dry 161 96 134 238 76 76 1Critical 132 89 150 241 69 58 -5

Precip-itation

504


709

Ground-water

Pumping374 Evapo-

trans-piration

851Deep Perc-

olation283

Runoff and

Return Flow453

Inflows Outflows


Precip-itation

98


6

Ground-water

Pumping36

Evapo-trans-

piration58

Deep Perc-

olation28

Runoff and

Return Flow55

Inflows Outflows

Precip-itation

313

Evapo-trans-

piration153

Deep Perc-

olation121

Runoff and

Return Flow38

Inflows Outflows

East ButteAverage Annual Water Budgets

Total Inflow/ Outflow

1,166 taf


(987 taf)

DevelopedLands

(38 taf)

Non-IrrigatedLands

(141 taf)

Precip-itation

269


598

Ground-water

Pumping120

Evapo-trans-

piration485

Deep Perco-lation147

Runoff and

Return Flow355Inflows Outflows

Precip-itation

31


2

Ground-water

Pumping5

Evapo-trans-

piration20

Deep Perco-lation

7

Runoff and

Return Flow12

Inflows Outflows

Precip-itation

141

Evapo-trans-

piration67

Deep Perco-lation

53

Runoff and

Return Flow22

Inflows Outflows

East Butte Overall Water Budget



Water Year


Change in

Storage (taf)

Precipi-tation

Surface Water

Ground-water

Evapotrans-piration

Deep Percolation

Runoff and

Return Flow


Above Normal

514 591 110 565 228 431 11

Below Normal

439 604 125 547 205 414 -4

Dry 381 611 129 594 185 338 1Critical 297 581 150 571 166 285 -11

Precip-itation

504


709

Ground-water

Pumping374 Evapo-

trans-piration

851Deep Perc-

olation283

Runoff and

Return Flow453

Inflows Outflows


Precip-itation

98


6

Ground-water

Pumping36

Evapo-trans-

piration58

Deep Perc-

olation28

Runoff and

Return Flow55

Inflows Outflows

Precip-itation

313

Evapo-trans-

piration153

Deep Perc-

olation121

Runoff and

Return Flow38

Inflows Outflows

North YubaAverage Annual Water Budgets

Total Inflow/ Outflow 170 taf


(94 taf)

DevelopedLands

(25 taf)

Non-IrrigatedLands

(51 taf) Precip-itation

51

Evapo-trans-

piration25

Deep Perco-lation

22

Runoff and

Return Flow

3

Inflows Outflows

Precip-itation

20


4

Ground-water

Pumping1

Evapo-trans-

piration11

Deep Perco-lation

7

Runoff and

Return Flow

7Inflows Outflows

Precip-itation

35


8

Ground-water

Pumping51

Evapo-trans-

piration51

Deep Perco-lation

28

Runoff and

Return Flow14

Inflows Outflows

North Yuba Overall Water Budget



Water Year


Change in

Storage (taf)

Precipi-tation

Surface Water

Ground-water

Evapotrans-piration

Deep Percolation

Runoff and

Return Flow


Above Normal

121 11 49 88 66 28 1

Below Normal

106 12 51 87 58 24 0

Dry 92 12 54 89 47 21 1Critical 68 12 58 85 38 16 -2

Water Budget Summary

• For the valley floor, groundwater pumping is approximately balanced by deep percolation in recent years• Irrigated agriculture and wetlands

represent the primary use of water and rely mainly on surface water for irrigation• Magnitude of inflows/outflows varies

widely by inventory unit (and subinventoryunit) and land use category


Dry Year Observations

• Decreases in deep percolation are greater than increases in pumping due to • Reduced recharge from precipitation• Reduced applied surface water

• Decreased recharge (deep percolation) and increased pumping likely contribute to observed groundwater level declines• Groundwater level declines in recent years

are likely primarily due to drought, rather than other factors (e.g. land use changes)


Recap/Wrap Up


Conclusions

• Land Use• Climate and Hydrology• Water Budgets


Land use as been relatively stable since 2000.


236 234 234 235

148 144 141 137

26 29 30 3042 44 47 50

0

50

100

150

200

250

300

350

400

450

500

1995-1999 2000-2004 2005-2009 2010-2014

Acre

s (Th

ousa

nds)


Annual precipitation and resulting runoff are highly variable.


0

2

4

6

8

10

12

14

16

197119721973197419751976197719781979198019811982198319841985198619871988198919901991199219931994199519961997199819992000200120022003200420052006200720082009201020112012201320142015

Sacr

amen

to V

alle

y W

ater

Year

Inde

x

Water Year

Wet Above Normal Below Normal Dry Critical

Update Period

Only 5 Above Normal orWet years out of 15.

Surface water supplies are relatively steady despite year-to-year differences in precipitation*.


0

100,000

200,000

300,000

400,000

500,000

600,000

700,000

800,000

900,000

1,000,000

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014

Annu

al D

iver

sions

(af)

Water Year

Feather River Ag Butte Creek Ag Sacramento River Ag Other Ag Developed

* Feather River ag supplies are reduced by approximately 300,000 af in curtailment years.

Variability in precipitation is a primary driver of groundwater pumping.


Wide range,depending largely

on year type.

Littlecorrelationwith time.

On the valley floor, groundwater pumping is approximately balanced by deep percolation*.


Precip-itation

914Applied Surface Water

715

Ground-water

Pumping411

Evapo-trans-

piration1,062Deep

Perc-olation

432

Runoff and

Return Flow546

Inflows Outflows

Average Annual Inflows and Outflows (thousands of acre-feet)

* Varies by inventory/subinventory unit. Includes only vertical fluxes.

Irrigated ag. and wetlands represent the primary developed use of water and rely mainly on surface water.


Precip-itation

504


709

Ground-water

Pumping374 Evapo-

trans-piration

851Deep Perc-

olation283

Runoff and

Return Flow453

Inflows Outflows

Precip-itation

98


6

Ground-water

Pumping36

Evapo-trans-

piration58

Deep Perc-

olation28

Runoff and

Return Flow55

Inflows Outflows

Precip-itation

313

Evapo-trans-

piration153

Deep Perc-

olation121

Runoff and

Return Flow38

Inflows Outflows


(1,587 taf)

DevelopedLands

(140 taf)

Non-IrrigatedLands

(312 taf)

Magnitude of inflows/outflows varies widely by inventory unit.

•Vina: 296,000 af•West Butte: 408,000 af•East Butte: 1,166,000 af•North Yuba: 170,000 af• Total: 2,038,000 af


Magnitude of inflows/ outflows varies widely by land use category.


Precip-itation

504


709

Ground-water

Pumping374 Evapo-

trans-piration

851Deep Perc-

olation283

Runoff and

Return Flow453

Inflows Outflows

Precip-itation

98


6

Ground-water

Pumping36

Evapo-trans-

piration58

Deep Perc-

olation28

Runoff and

Return Flow55

Inflows Outflows

Precip-itation

313

Evapo-trans-

piration153

Deep Perc-

olation121

Runoff and

Return Flow38

Inflows Outflows


(1,587 taf)

DevelopedLands

(140 taf)

Non-IrrigatedLands

(312 taf)

Dry Year Observations

• Decreases in deep percolation are greater than increases in pumping due to • Reduced recharge from precipitation• Reduced applied surface water

• Decreased recharge (deep percolation) and increased pumping both contribute to observed groundwater level declines• Groundwater level declines in recent years

are likely primarily due to drought, rather than other factors (e.g. land use changes)


Recommendations•Methodology

• Continue work with local stakeholders to document diversions, including riparian diversions and water supplies for managed wetlands.

• Verify and refine groundwater pumping estimates by obtaining pumping data from cooperative landowners.

• Further investigate the fate of deep percolation from agricultural lands.

• Refine water budgets for developed lands.


Recommendations (continued)• Continue outreach to educate and inform

the public regarding water resources in the County and to gather additional insights.• Continue process of updating and

calibrating the BBGM.• Continue to assess the use of WI&A

information to support development of GSPs under SGMA.


Recommendations (continued)

• Further evaluate BBGM water budgets from historical and current drought periods to better understand factors contributing to recent historic low water levels in some areas.• Identify and evaluate additional options to

adapt to future demands and climate change


Acknowledgements

•Department of Water and Resource Conservation staff•Project Advisory Committee• Local Water Suppliers and Managers•U.C. Cooperative Extension•California Department of Water

Resources•Butte County Water Commission


Questions/Discussion


draft 2016 water inventory and analysis report · •april– pac review of initial draft wi&a...

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