This document summarizes a project to assess agricultural sensitivity to climate change and water resources interactions in California's San Joaquin Valley. The project will use modeling tools and data to analyze potential adaptation strategies, including augmenting water supplies through groundwater recharge and reservoir management, and adjusting cropping strategies. The economic impacts of different adaptation scenarios will also be evaluated. The goal is to identify sustainable solutions that mitigate climate change pressures on agriculture in the region.

1. Agricultural sensitivity
to climate change and water resources interactions
in the San Joaquin Valley, Calif. and
system resilience offered by adaptation strategies
Presenter:
Philip Bachand
Bachand & Associates
530-758-1336
philip@bachandassociates.com
12/22/2016 1

2. Critically
Overdrafted
Groundwater
Basins, 2016
12/22/2016 2

3. Management
Plan
Climate Change
Local
Adaptation
Regional
Adaptation
Reservoir
Management
Rain / Snow
Runoff
Temp / Precipitation / ET / CO2
Land UseGroundwater
Supplies
Surface
Water
Supplies
Water Transfers
Conjunctive Use
Recharge and
Withdrawals
ISNOBAL
CalSim
C2VSIM
WUE
NUE
CO2 fertilization
Ag Literature and Databases
Cultural
Practices
Crop Yield
Water
Resources
Water Quality
Outcomes
Anthropogenic Feedback
Mechanisms
Estimated NPV:
Total and by groups
and subwatersheds
Economic Model
WARMF
Land Use
Precip
SJV Stream
flow and
quality
Irrigation
Fertilization
Tetra Tech
Sujoy Roy, pH.D., Lead
TASK 3
Tetra Tech and UC Davis LAWR
Philip Bachand, pH.D., Lead
TASK 5
UC Davis LAWR and Tetra Tech
Dr. Lucas Silva, pH.D. Lead
TASK 1
Systech and
Tetra Tech
Joel Herr, Lead
TASK 3
UC Merced and Tetra Tech
Prof Rob Rice, pH.D. Lead
TASK 2
UCD ARE
Dr Leslie Butler, Lead
TASK 4

4. Key questions identified in the proposal
• What magnitude of change is required in water management to
address changes in precipitation timing, frequency and type, and in
snowpack water storage?
• What cropping strategies are likely to sustainably mitigate climate
change pressures and how will those affect crop distribution in the
SJV?
• How sensitive, robust and resilient are these cropping strategies to
the evolving climate change / water paradigm?
• What are the economics behind adaptation strategies at the local and
regional scale?
12/22/2016 4

5. Reservoir Operation - Today
Surface
Water
Supply Demand
Oct Nov Dec Jan Feb Mar Apr May Jun July Aug Sep
Reservoirs
• Surface Water Supply
• From Sierra runoff
• Demand
• Agricultural demand dominates
demand
• Reservoirs
• Managed to mitigate floods and
meet demand curve
12/22/2016 5

6. Reservoir Operation - Today
Surface
Water
Supply
Oct Nov Dec Jan Feb Mar Apr May Jun July Aug Sep
Reservoirs
• Surface Water Supply
• From Sierra runoff
• Demand
• Agricultural demand dominates
demand
• Reservoirs
• Managed to mitigate floods and
meet demand curve
12/22/2016 6
Groundwater
Demand

7. Watershed of the
Sacramento-San Joaquin
Delta and Regions that Use
Delta Water CVP Target--
• Serves 2M Ac Irr. Ag
• Delivers 7M Ac-ft
• 70% to Ag
• 9% to Urban
• 11% to wildlife
State Target --
• Serves 0.75M Ac Irr. Ag
• Delivers 3M Ac-ft
• 30% to Ag
• 70% to Urban
Total SWP Annual Delivery (1000 Ac-FT), DWR 2015
12/22/2016 7

8. 2014 Sustainable Groundwater Management Act
(SGMA)
Sustainable Yields & Undesirable Results
• “Sustainable yield,” according to the SGMA, means the maximum quantity
of water – calculated over a base period representative of long-term
conditions in the basin that can be withdrawn annually from a
groundwater supply without causing an undesirable result.
• Undesirable Results:
 Chronic lowering of groundwater levels (excluding reductions in groundwater
levels during drought if offset during other periods)
 Significant and unreasonable reductions in groundwater storage;
 …. seawater intrusion;
 …. degradation of water quality;
 …. land subsidence; and
 Surface water depletions that have significant and unreasonable adverse impacts
on beneficial uses.
12/22/2016 8

9. Conveyance and Exports in California’s Water Budget
1873 TODAY
Sacramento
River
Sacramento
River
San Joauqin
River
San Joauqin
River
CVP (Federal)
and SWP (State)
Diversions
12/22/2016 9

10. The San Joaquin
Water Budget
Surface Transports
Surface
Storage
Use
Loss
F=
• Precipitation(t)=
F(Climate = F(Climate
Change)
• Infiltration(t) = F(Soils,
Geology, etc…)
• Evapotranspiration(t) =
F(Climate = F(Climate
Change))
• Other(t)
• Delta Flows and Mgmt
• Capacity(t)
• Conveyance(t)
• Management(t)
• Inefficiencies(t)
• Costs(t)
F=
• Demand of
Sectors(t)= F[ ]
• Recycling(t)
• Reuse(t)
• Conservation
• Hard Needs
• Soft Needs =
F(Wealth, etc…)
• Costs(t)
F=
(t)(t)
(t)
Groundwater Supply
(? MAF Overdraft
Annually) (t)
Sierra Runoff
(t)
(t)
12/22/2016 10

11. Complying with the Biological
Opinions to comply with
Endangered Species Act
State and/or Federal Listing Status of Native Fish Species
Common Name Scientific Name Listing Status
Delta smelt Hypomesus transpacificus FT, SE
longfin smelt Spirinchus thaleichthys FC, ST
Chinook salmon, Central Valley
spring-run ESU
Onorhynchus tshawytscha FT, ST
Chinook salmon, Sacramento
River winter-run ESU
Onorhynchus tshawytscha FE, SE
steelhead, Central Valley DPS Onorhynchus mykiss FT
green sturgeon DPS Acipenser medirostris FT
F = Federally-listed under ESA | E = Endangered | C = Candidate Species for Listing|
ESU = Evolutionary Significant Unit | S = State-listed under CESA | T = Threatened |
DPS = Distinct Population Segment
12/22/2016 11
The CVP/SWP operations are informed
through a structured decision making
process designed to reduce the adverse
effects on federally and state listed fish
species.

12. SGMA Supply Augmentation – Water
Available
• Potential water sources
• Surface water
• Recycled water
• Conserved water
• Brackish or saline water, Desalination
• Transferred water
• Other
• Aquifer replenishment
• In lieu recharge
• Direct recharge
• Uncertainties
• Climate change
• Institutional / regulatory
constraints
• Regional and local challenges
and implementation strategies
• State Water Project and
Central Valley Project
• System reoperation
12/22/2016 12

13. Future Opportunities and Considerations towards Supply
Augmentation and Demand Reduction
• Sustainable Yield (SGMA)
• WUE and NUE (Demand; Agriculture; Horwath, et al)
• Estimating regional overdraft from cropping data (Demand; Agriculture; Bachand)
• Sierra Water Deliveries
• Sierra Nevada Runoff Timing and its Variance (Supply; Water; Rice et al)
• Sierra Nevada Runoff Annual Volume Reductions (Supply, Water; Rice et al)
• Augmenting Water Supplies
• On-Farm Recharge and Agricultural Water Banking (Supply; Water; Bachand et al)
• Reservoir and Water System Re-operation (Supply; Water, Bachand, Sujoy, et al)
• Within and Outside Water Transfers (Supply; Water; Roy, Herr et al)
• Delta Management under Climate Change (Supply; Water, Roy, Herr et al)
• Economics
• Land Fallowing and Retirement (Demand; Agriculture; Butler et al.)
• Water Markets (Supply; Water; Butler et al.)12/22/2016 13

14. NASS
Database
*5
*
*
*
*WARMF Estimates
*
*
Silva,
Maxwell,
Horwath et
al, 2016
12/22/201614

15. Task 1. Quantify relationships between crop yields,
farm practices, and possible environmental impacts.
Key Issue. Viability of agricultural efficiency depend upon
crop response to changes in climate and atmospheric
composition.
Specifically we want to know:
• What will be the net impact of climate change
and rising CO2 on crop WUE and NUE?
• How will these changes affect yield quantity and
quality of different crops?
• How will these impacts change water, carbon and
nutrient cycles at the regional level?
12/22/2016 15
Silva,
Maxwell,
Horwath et
al, 2016

16. Changes in irrigated land inputs from 2007 – 2012
(2012 USDA NASS Census Report)
Characteristics Units
2012 2007 2012:2007 2012 2007 2012:2007
Land in farms acres 16,039,761 16,231,930 99% 9,529,240 9,132,765 104%
Irrigated land acres 7,861,964 8,016,159 98% 167,332 0%
Market value of agricultural
products sold $1,000
37,327,971 29,586,599 126%
5,299,501 4,298,465
123%
Total farm production expenses $1,000 30,233,225 23,015,562 131% 5222442 3,947,079 132%
Fertilizer, lime, and soil
conditioners purchased $1,000
1,793,731 1,294,928 139%
12,331 19,247
64%
chemicals purchased $1,000 2,171,784 1,347,595 161% 18,889 21,537 88%
Gasoline, fuels, and oils purchased $1,000
1,402,954 998,021 141%
22,203 26,296
84%
Utilities $1,000 1,571,566 1,132,624 139% 112,777 98,923 114%
Irrigated Farms, Any land irrigated Nonirrigated Farms
Understanding current water
demand and trends based as
cultural practices are changing
12/22/201616

17. Task 1. Quantify relationships between crop yields,
farm practices, and possible environmental impacts.
Key Issue. Changing cultural and irrigation practices
have affected crop inputs, per acre efficiencies and per
acre yields.
Specifically we want to know:
• What effects do the changing practices have on
crop distribution and regional inputs, including
water demand?
• How are these factors affecting surface and
ground- water demand?
12/22/2016 17

18. Task 1 – Upcoming Steps
• Viability of agricultural efficiency depend upon crop response to
changes in climate and atmospheric composition.
• Silva, Maxwell, Horwath et al are assessing these effects.
• Assessing CO2 effects on WUE and NUE using available datasets and modeling
based upon plant physiology.
• Inputting data into water quality model (ie. WARMF)
• The effects of changing agricultural practices on local and
regional water use
• Bachand, Silva et al
• Using available NASS, DWR and other data sets to assess how changes in
agriculture have affects water use and groundwater pumping
12/22/2016 18

19. Future Opportunities and Considerations towards Supply
Augmentation and Demand Reduction
• Sustainable Yield (SGMA)
• WUE and NUE (Demand; Agriculture; Horwath, et al)
• Estimating regional overdraft from cropping data (Demand; Agriculture; Bachand)
• Sierra Water Deliveries
• Sierra Nevada Runoff Timing and its Variance (Supply; Water; Rice et al)
• Sierra Nevada Runoff Annual Volume Reductions (Supply, Water; Rice et al)
• Augmenting Water Supplies
• On-Farm Recharge and Agricultural Water Banking (Supply; Water; Bachand et al)
• Reservoir and Water System Re-operation (Supply; Water, Bachand, Sujoy, et al)
• Within and Outside Water Transfers (Supply; Water; Roy, Herr et al)
• Delta Management under Climate Change (Supply; Water, Roy, Herr et al)
• Economics
• Land Fallowing and Retirement (Demand; Agriculture; Butler et al.)
• Water Markets (Supply; Water; Butler et al.)12/22/2016 19

20. On-Farm Flood Capture
Definition and Vision
• Available = Physical, Legal
• Leveraging Private Lands
• Dual Use Farm and Flood
• Design into Farm Management
• Leveraging Community Resources
Capturing Available Flood Flows onto Farm
Lands for Groundwater Recharge and to
Mitigate Downstream Flood Risks
12/22/2016 20

21. 12/22/2016 21
Flood Flow Thru the James
Bypass
Winter Flooding of Row Crop
Fields

22. Acreage needed to offset 1M ac-ft overdraft
for different Periods and Rates of Infiltration
12/22/2016 22
0
200,000
400,000
600,000
800,000
1,000,000
1,200,000
1,400,000
1,600,000
2 4 6 8
4
8
12
Infiltration Rates (in/d)
Period (weeks)
AcresRequired

23. Regional Considerations for
On-Farm Flood Recharge
Opportunities for Recharge
due to high precipitation
Reservoir / Water System
Reoperation
Water Transfer Opportunities
12/22/2016 23
Dahlke et al, 2016
Yield Potential

24. Summary To Date
• Project ranges across water, agriculture, economics and climate change
• California’s regulatory climate (e.g. SGMA) is a main driver for potential solutions
• Modeling tools that are being used to assess opportunities and scenarios include CA hydrologic
models, agricultural datasets and public databases, runoff models and economic models including
the Statewide Agricultural Production Model.
• Collaborators from public and private groups
• Scenarios being defined in conversations with stakeholders and in consideration of climate
changes and California’s regulatory response:
• Augmenting water supplies (e.g. recharge, reservoir re-operation)
• Changing crops and cropping practices (e.g. specialty/high value crops, fallowing, dry land farming)
• Will assess economic effects on agricultural production using SWAP model.
12/22/2016 24