Central Valley Project Integrated Resource Plan

Home , American River, Central Valley Project, Red Bluff Diversion Dam

Summary Report Central Valley Project Integrated Resource Plan

U.S. Department of the Interior Bureau of Reclamation Mid-Pacific Region

TABLE OF CONTENTS

BACKGROUND...... 5 STUDY APPROACH...... 7 CLIMATE IMPACTS ON WATER SUPPLIES AND DEMANDS...... 11 COMPARISON OF PROJECTED WATER SUPPLIES AND DEMANDS...... 21 PERFORMANCE OF POTENTIAL FUTURE WATER MANAGEMENT ACTIONS...... 27 PORTFOLIO TRADEOFFS...... 37 CVP IRP STUDY LIMITATIONS...... 39 ACRONYMS AND ABBREVIATIONS USED IN FIGURES...... 41

Tables

Table 1. Simulation Suites and Assumptions Inlcuded in Each Portfolio...... 27

Figures

Figure 1a. Projected changes in Temperature in Ensemble-Informed Transient Climate Scenarios between 2012 and 2099 for a Representative Grid Cell in the American River Basin (Example). Q5 represents the central tendency. 10th – 90th percentile projections include Q1 (drier, less warming), Q2 (drier, more warming), Q3 (wetter, more warming) and Q4 (wetter, less warming). Note: Appendix I. explains the acronyms and abbreviations used in the figures...... 8 Figure 1b. Projected changes in Precipitation in Ensemble-Informed Transient Climate Scenarios between 2012 and 2099 for a Representative Grid Cell in the American River Basin (Example). Q5 represents the central tendency. 10th – 90th percentile projections include Q1 (drier, less warming), Q2 (drier, more warming), Q3 (wetter, more warming) and Q4 (wetter, less warming). Note: Appendix I. explains the acronyms and abbreviations used in the figures...... 9 Figure 2a. Annual Time Series from 2012 to 2099 of Surface Water Flows in TAF/yr for the Sacramento River for each Climate Scenario under Current Trends (CT) socioeconomic scenario...... 12 Figure 2b. Annual Time Series from 2012 to 2099 of Surface Water Flows in TAF/yr for the San Joaquin River for each Climate Scenario under Current Trends (CT) socioeconomic scenario...... 13 Figure 3a. Projected Changes in Annual Surface Water Flows in TAF/yr between 2012 and 2099 in the Sacramento River for each Climate Scenario Relative to the Historic Period Simulation (1915-2003)...... 14 Figure 3b. Projected Changes in Annual Surface Water Flows in TAF/yr between 2012 and 2099 in the San Joaquin River for each Climate Scenario Relative to the Historic Period Simulation (1915-2003)...... 15 Figure 4a. Simulated Period Average Monthly Runoff in the Sacramento River Basin for each Climate Scenario...... 16 Figure 4b. Simulated Period Average Monthly Runoff in the San Joaquin River Basin for each Climate Scenario...... 17 Figure 5. Annual Applied CVP Agricultural Water Demand in TAF/yr for each Socioeconomic-Climate Scenario...... 18 Figure 6. Annual Time Series of Urban Water Demands from 2012 to 2099 in the CVP Service Area in Each of the Socioeconomic (CT,SG, EG) and Climate projections (noCC, Q1, Q2, Q3, Q4, Q5) scenario combinations...... 20 Figure 7a. Annual Time Series of Unmet Water Demands from 2012 to 2099 in the CVP Service Area for Selected Socioeconomic-Climate Scenarios - Current Trends – No Climate Change (CT-noCC) - Average Unmet Demand – 4.2 MAF...... 22 Figure 7b. Annual Time Series of Unmet Water Demands from 2012 to 2099 in the CVP Service Area for Selected Socioeconomic-Climate Scenarios - Current Trends – Central Tendency (CT-Q5) - Average Unmet Demand – 5.1 MAF...... 23 Figure 7c. Annual Time Series of Unmet Water Demands from 2012 to 2099 in the CVP Service Area for Selected Socioeconomic-Climate Scenarios - Expansive Growth – More Warming, Drier (EG-Q2) - Average Unmet Demand – 7.9 MAF...... 24

Central Valley Project Integrated Resource Plan Summary Report 3 TABLE OF CONTENTS

Table of Contents - Continued

Figure 7d. Annual Time Series of Unmet Water Demands from 2012 to 2099 in the CVP Service Area for Selected Socioeconomic-Climate Scenarios - Slow Growth – Less Warming, Wetter (SG-Q4) - Average Unmet Demand – 3.2 MAF...... 25 Figure 8. Average Annual Unmet CVP Demands for each Portfolio and Scenario...... 30 Figure 9. Average Annual Total Delta Exports (TAF/yr) for each Portfolio and Scenario...... 30 Figure 10. Average Annual Delta Outflows (TAF/yr) for each Portfolio and Scenario...... 31 Figure 11. Average Annual February-to-June X2 Locations for each Portfolio and Scenario...... 31 Figure 12. Change in Mean Daily Temperature on Sacramento River at Jelly’s Ferry from July to September for each Portfolio and Scenario Relative to their Baselines...... 33 Figure 13. Change in Net Hydropower Generation in CVP and SWP systems for each Portfolio and Scenario Relative to their Baselines...... 33 Figure 14. Change in Net GHG emissions in CVP and SWP systems for each Portfolio and Scenario Relative to their Baselines...... 34 Figure 15. Changes in Average Annual Agricultural and Urban Economic Benefits in the CVP Service Area for each Portfolio and Scenario Relative to their Baselines...... 35

4 Central Valley Project Integrated Resource Plan Summary Report BACKGROUND

BACKGROUND

The Central Valley Project Integrated Resource twenty-first century challenges. These strategies Plan (CVP IRP) study continues and expands on are evaluated against key CVP performance the long-range planning activities of the Central criteria to compare their potential effectiveness Valley Project Yield Feasibility Investigation under a broad range of future socioeconomic- by addressing future uncertainties in climate climate uncertainties, and to identify tradeoffs as well as changing socioeconomic conditions. among various delivery reliability, water quality, To better understand future challenges, the environmental, hydropower, and urban and CVP IRP study focuses on providing more agricultural economic performance characteristics. comprehensive assessments of potential climatic Finally, it is envisioned that the CVP IRP will and socioeconomic uncertainties for the entire serve as an important background document for CVP Service Area and each of the CVP Divisions. the Sacramento-San Joaquin River Basins Study The study explores various portfolios of system- (SSJRBS), which received funding under the wide and local water management actions WaterSMART grant program. that might be employed to adapt to potential

Central Valley Project Integrated Resource Plan Summary Report 5

STUDY APPROACH

The CVP IRP study employed a scenario-based through Q4 projections each include the 10 analytical approach. Existing operational, ensemble members closest to the 10th and 90th hydrologic, water quality, hydropower, urban and percentile of changes to capture a significant range agricultural economic models were integrated of the uncertainty in the 112 member ensemble. into a suite of decision support tools for assessing the effects of future socioeconomic-climate In addition to assessing the impacts of future uncertainties on CVP and its Divisions. Future climate change on water supply, an important socioeconomic-climate uncertainties were objective of CVP IRP study was to evaluate the characterized by combining three potential corresponding effects of climate change on water socioeconomic and six representative climate demands. For this purpose, projections of changes futures to form 18 future scenarios. Each scenario in solar radiation, atmospheric humidity and wind was simulated with conditions continuously speed were developed to evaluate changes in crop changing from present day to the end of the 21st evapotranspiration (ET). These meteorological century. conditions were not readily available from GCM simulations. Consequently, an analysis of long- The current trends, slow and expansive growth term historic observations at four representative socio-economic scenarios based on population California Irrigation Management System and land use changes developed for the California meteorological stations was performed to develop Water Plan through year 2050 were extended to the information necessary to estimate solar year 2100 using other North American population radiation, atmospheric humidity and wind speed projections. Transient future climate projections from the projections of future temperature and were developed from an ensemble of 112 bias precipitation. Carbon dioxide (CO2) also has corrected spatially downscaled global climate significant effects on both crop ET and yield. model (GCM) simulations. One historical and Projected changes in CO2 were obtained directly five statistically representative future temperature from the proportion of individual projections and precipitation projections were developed to included in each of the statistically representative characterize the central tendency and the range climate projections. of the ensemble uncertainty including projections representing drier, less warming; drier, more The modeling approach involved first simulating warming; wetter, more warming; and wetter, less the effects from projected climate change on warming conditions than the median projection. the evapotranspiration (ET) and yields of the The observed natural variability in the historic major agricultural crops grown in Central Valley climate between 1915 and 2003 was used to create of California. For each socioeconomic-climate the same inter-annual variability in the projected scenario, these projected crop ETs along with climates. Transient sea level rise projections urban and environmental demands were used corresponding with projected climate change were as inputs to an integrated hydro-climate model also developed for the Sacramento-San Joaquin (WEAP-CV) to simulate snowpack accumulation Delta. and runoff; reservoir operations and river flows; surface water diversions and return flows; and Figure 1 shows an example of the five transient groundwater recharge and pumping. These temperature and precipitation projections used in hydrological responses to socioeconomic-climate the CVP IRP study to represent climate uncertainty scenarios were then used as inputs to the CVP IRP in the 21st century. The central tendency (Q5) CalLite model. This model was used to simulate includes ensemble members between the 25th to the coordinated operations of the CVP and State 75th percentiles of temperature and precipitation Water Project (SWP) as well as other Central change relative to the historic climate. The Q1 Valley non-project water management systems Central Valley Project Integrated Resource Plan Summary Report 7 STUDY APPROACH

8 Central Valley Project Integrated Resource Plan Summary Report STUDY APPROACH

Figure 1b. Projected changes in Precipitation in Ensemble-Informed Transient Climate Scenarios between 2012 and 2099 for a Representative Grid Cell in the American River Basin (Example). Q5 represents the central tendency. 10th – 90th percentile projections include Q1 (drier, less warming), Q2 (drier, more warming), Q3 (wetter, more warming) and Q4 (wetter, less warming). Note: Appendix I. explains the acronyms and abbreviations used in the figures.

Central Valley Project Integrated Resource Plan Summary Report 9 STUDY APPROACH under current regulatory requirements. The CVP (Sacramento and San Joaquin) and Delta water IRP CalLite model is a screening tool, which quality (salinity), hydropower (CVP and SWP) was specially developed to quantify the impacts and municipal (Central Valley and South Bay) of changes in hydro-climate on water supplies and agricultural economics (SWAP) models to and demands in the CVP Service Area and its evaluate key CVP-SWP performance metrics. Divisions. By design, it also facilitates analyses A new greenhouse gas (GHG) model was also of the effectiveness of a wide variety of potential developed to evaluate the effects of potential changes in management and infrastructure on changes in hydropower generation on CVP-SWP imbalances between future surface and ground GHG emissions. water supplies and CVP-SWP water demands. The CVP IRP CalLite model was also designed to interface with existing river water temperature

10 Central Valley Project Integrated Resource Plan Summary Report CLIMATE IMPACTS ON WATER SUPPLIES AND DEMANDS

CLIMATE IMPACTS ON WATER SUPPLIES AND DEMANDS Model runs were performed to estimate the tendency (Q5) projected flows are only slightly projected annual time series of surface water different than historic flows, the wetter projections runoff in the Sacramento River system upstream (Q3, Q4) result in increased river flows in both the of Hood and in the San Joaquin River system Sacramento and San Joaquin rivers whereas flows upstream of Vernalis for each of the 18 transient in the drier projections (Q1, Q2) are less than in socioeconomic-climate scenarios from 2012 to historic period. 2099. Figure 2 shows projected runoff for each of the 5 climate change scenarios under current Figure 4 shows the simulated monthly period trends growth (CT) as well as a no climate change average flows in the Sacramento River and (noCC) condition. The 10-year moving average San Joaquin River basins for each projected for the central tendency (Q5) climate projection is climate from 2012 through 2099 assuming also shown. the CT socioeconomic scenario. Each basin has a different monthly pattern reflecting their Figure 2, does not show surface water flow differences in hydro-climate, topography projections for the slow growth (SG) and and terrestrial conditions. In both basins, expansive growth (EP) scenarios to allow the the magnitude of flows reflects the projected graph to be readable. In general, differences in precipitation. The wetter projections (Q3,Q4) river flows among the different socioeconomic have flows greater than historic conditions scenarios associated with the same climate especially in the Fall and Winter months whereas projection are small because the flow impact is the drier projections (Q1,Q2) have less. The limited to the overall impact of changed water central tendency projection (Q5) is similar to the demands under the various socioeconomic historic (CT No CC) but with increased early scenarios. As explained in more detail in the water year flows. In the generally lower elevation, demand discussion starting on page 10, the rainfall dominated Sacramento River basin, the more robust growth scenarios result in increased climate projections have a similar pattern to the demands for urban water supplies. However, no climate change scenario. In higher elevation, urban growth is assumed to be accompanied more snowpack affected San Joaquin basin, a by conversion of some agricultural to urban projected shift in runoff from the spring months land resulting in a corresponding decrease in to the winter months occurs. This projected shift agricultural water demands. The offsetting nature occurs because higher future temperatures during of urban and agricultural demands coupled with the winter season result in more precipitation the fact that urban demands are a relatively small occurring as rainfall along with earlier snowmelt component of total water demands explains the runoff. This shift in timing becomes more negligible overall impact of the socioeconomic pronounced during the 21st century as temperature scenarios on river flows. However, there are increases become larger (not shown). substantial differences in flows among the different climate projections. A general trend Figure 5 shows the annual time series of projected toward increasing high flow magnitude occurs in applied agricultural water demands within the both river systems during the twenty-first century. CVP Service Area for each the 18 socioeconomic- These projected time series reflect the inter- climate scenarios. Unlike water supplies, annual variability of the historical period because demands are significantly affected by both the of the methodology used in developing the socioeconomic scenarios and projected climate projections. Figure 3 shows the changes in annual change. In all the socioeconomic scenarios, there flow for the 5 representative climate projections is an assumption that some agricultural land is relative to the historic climate assuming the converted to urban uses. The magnitude of these CT socioeconomic scenario. While the central assumed land use changes increase over time with Central Valley Project Integrated Resource Plan Summary Report 11 CLIMATE IMPACTS ON WATER SUPPLIES AND DEMANDS

Sacramento River

Figure 2a. Annual Time Series from 2012 to 2099 of Surface Water Flows in TAF/yr for the Sacramento River for each Climate Scenario under Current Trends (CT) socioeconomic scenario

12 Central Valley Project Integrated Resource Plan Summary Report CLIMATE IMPACTS ON WATER SUPPLIES AND DEMANDS

San Joaquin River

Figure 2b. Annual Time Series from 2012 to 2099 of Surface Water Flows in TAF/yr for the San Joaquin River for each Climate Scenario under Current Trends (CT) socioeconomic scenario

Central Valley Project Integrated Resource Plan Summary Report 13 CLIMATE IMPACTS ON WATER SUPPLIES AND DEMANDS

Sacramento River

Figure 3a. Projected Changes in Annual Surface Water Flows in TAF/yr between 2012 and 2099 in the Sacramento River for each Climate Scenario Relative to the Historic Period Simulation (1915-2003).

14 Central Valley Project Integrated Resource Plan Summary Report CLIMATE IMPACTS ON WATER SUPPLIES AND DEMANDS

San Joaquin River

Figure 3b. Projected Changes in Annual Surface Water Flows in TAF/yr between 2012 and 2099 in the San Joaquin River for each Climate Scenario Relative to the Historic Period Simulation (1915-2003).

Central Valley Project Integrated Resource Plan Summary Report 15 CLIMATE IMPACTS ON WATER SUPPLIES AND DEMANDS

Sacramento River

Figure 4a. Simulated Period Average Monthly Runoff in the Sacramento River Basin for each Climate Scenario

16 Central Valley Project Integrated Resource Plan Summary Report CLIMATE IMPACTS ON WATER SUPPLIES AND DEMANDS

San Joaquin River

Figure 4b. Simulated Period Average Monthly Runoff in the San Joaquin River Basin for each Climate Scenario

Central Valley Project Integrated Resource Plan Summary Report 17 CLIMATE IMPACTS ON WATER SUPPLIES AND DEMANDS

Figure 5. Annual Applied CVP Agricultural Water Demand in TAF/yr for each Socioeconomic-Climate Scenario.

18 Central Valley Project Integrated Resource Plan Summary Report CLIMATE IMPACTS ON WATER SUPPLIES AND DEMANDS the least change occurring in the Slow Growth In general, the applied agricultural water demands (SG) scenario and the most in the Expansive decrease during the 21st century because of both (EG) scenario. Projected climate change also the assumed reductions in irrigated land area affects agricultural water demands. Changes in and the effects of climate change on crop growth temperature, solar radiation, atmospheric humidity, and ET. Both of these factors contribute to the wind speed and carbon dioxide have different overall decrease in agricultural water demands crop-specific effects on the water needs of the by the end of the 21st century. Because the major crops grown in the Central Valley. agricultural applied water demands reflect the objective of maintaining optimum soil moisture For example, increased temperature may result conditions throughout the growing season by in increased crop ET until a crop’s optimum irrigating whenever precipitation is not sufficient temperature range is exceeded resulting in reduced to meet optimum crop water requirements, the growth and a corresponding decline in water use. drier climate projections (Q1,Q2) result in higher However, increasing carbon dioxide can both agricultural water demands. It is important to stimulate crop growth and reduce transpiration note that the rapid increase in agricultural water thereby increasing a crop’s water use efficiency. demands in the early 21st century shown on Figure Furthermore, climate change can also affect 5 is an artifact of several factors including the the rate of crop growth as well as planting and use of the 20th century historical climate (1930’s harvest dates. For annual crops, a shorter growing drought period) to characterize inter-annual season due to more rapid growth may result in climate variability in developing the transient 21st less water use whereas for perennial crops a century projections, higher agricultural land use longer growing season due to increased early in the early 21st century and the limited amount and late season temperatures may result in more of climate change that has occurred prior to and water use. In the CVP IRP study, these complex during this period. If a similar drought in the late relationships were simulated to determine the net 21st century had been simulated, the magnitude of effect of the socioeconomic-climate scenarios applied water demands would have been reduced. on agricultural water demands by assuming that there would be no changes in the current mixture Figure 6 presents the annual time series of of crops and cultivars as well as planting dates projected total urban demands within the CVP and management practices. However, as irrigated Service Area for the 18 socioeconomic-climate acreage declines during the 21st century due scenarios. In contrast to agricultural demands, to urban growth, results from the State Wide urban demands in the CVP Service Area are Agricultural Production (SWAP) model were used strongly correlated with the socioeconomic to simulate which crops farmers would continue scenarios and show only slight variations with to irrigate assuming future crop selections are projected climate change. Because the urban made to obtain optimum economic benefits. demands are driven largely by population, they Consequently, the CVP IRP study results may be tend to change steadily over time with the growth interpreted as an assessment of the need for the in population and expansion in commercial development of effective strategies to adapt for activities. Urban demand is only slightly changed current crop characteristics, management practices under Slow Growth (SG) conditions but increases and technologies. significantly under the Current Trends (CT) and Expansive Growth (EG) scenarios.

Central Valley Project Integrated Resource Plan Summary Report 19 CLIMATE IMPACTS ON WATER SUPPLIES AND DEMANDS

Figure 6. Annual Time Series of Urban Water Demands from 2012 to 2099 in the CVP Service Area in Each of the Socioeconomic (CT,SG, EG) and Climate projections (noCC, Q1, Q2, Q3, Q4, Q5) scenario combinations.

20 Central Valley Project Integrated Resource Plan Summary Report COMPARISON OF PROJECTED WATER SUPPLIES AND DEMANDS

COMPARISON OF PROJECTED WATER SUPPLIES AND DEMANDS A comparison of projected water supplies and tendency (CT-Q5), upper (EG-Q2), and lower demands in the CVP Service Area was performed (SG Q4) range of potential future unmet demands. to characterize the occurrence and potential range The no climate change simulation (CT-noCC) is of unmet demands in the CVP Service Area. The also included for comparative purposes. Over assumptions used in these Baseline simulations the twenty-first century, average annual unmet included the 2008 Fish and Wildlife Service and demands ranged from 2.7 to 8.2 MAF/year 2009 National Marine Fisheries Service Biological across the range of the 18 socioeconomic-climate Opinions, State Water Resources Control Board scenarios. These unmet demands occurred Water Quality Control Plan (D-1641) and other predominantly in the South-of-Delta Divisions criteria associated with the coordinated operations (San Felipe, West San Joaquin, and Friant). In of the CVP and SWP. general, unmet demands decrease as the rate of growth and climate warming are reduced and Figure 7 shows annual time series of groundwater, when precipitation is wetter than historic. Such surface water, local project supplies, and unmet conditions contribute to both reduced overall demands for four socioeconomic-climate demands and increased supplies of both surface scenarios, selected to represent the central and groundwater.

Central Valley Project Integrated Resource Plan Summary Report 21 COMPARISON OF PROJECTED WATER SUPPLIES AND DEMANDS

Figure 7a. Annual Time Series of Unmet Water Demands from 2012 to 2099 in the CVP Service Area for Selected Socioeconomic-Climate Scenarios - Current Trends – No Climate Change (CT-noCC) - Average Unmet Demand – 4.2 MAF

22 Central Valley Project Integrated Resource Plan Summary Report COMPARISON OF PROJECTED WATER SUPPLIES AND DEMANDS

Figure 7b. Annual Time Series of Unmet Water Demands from 2012 to 2099 in the CVP Service Area for Selected Socioeconomic-Climate Scenarios - Current Trends – Central Tendency (CT-Q5) - Average Unmet Demand – 5.1 MAF

Central Valley Project Integrated Resource Plan Summary Report 23 COMPARISON OF PROJECTED WATER SUPPLIES AND DEMANDS

Figure 7c. Annual Time Series of Unmet Water Demands from 2012 to 2099 in the CVP Service Area for Selected Socioeconomic-Climate Scenarios - Expansive Growth – More Warming, Drier (EG-Q2) - Average Unmet Demand – 7.9 MAF

24 Central Valley Project Integrated Resource Plan Summary Report COMPARISON OF PROJECTED WATER SUPPLIES AND DEMANDS

Central Valley Project Integrated Resource Plan Summary Report 25

PERFORMANCE OF POTENTIAL FUTURE WATER MANAGEMENT ACTIONS

PERFORMANCE OF POTENTIAL FUTURE WATER MANAGEMENT ACTIONS The CVP IRP study included the analysis of a Table 1. Simulation Suites and Assumptions Inlcuded in variety of potential water management actions Each Portfolio that were grouped into thematic portfolios Portfolio designed to achieve particular objectives. These Assumption A C D E portfolios were analyzed by simulating each one Baseline assumptions X X X X using the 18 socioeconomic-climate scenarios to characterize the range of their potential Local actions Modest Ag and M&I X X X X effectiveness relative to future socioeconomic- Conservation climate uncertainties and to assess what tradeoffs Municipal Recycling and X X relative to key CVP performance metrics might Desalination occur. In the CVP IRP study, no attempt was Aggressive Ag and M&I X X made to find an optimum combination of actions Conservation nor to make recommendations relative to future Systemwide Actions implementation. In addition, the CVP IRP Delta Conveyance X X modeling tools were developed and applied Shasta Lake Enlargement X X with intent of characterizing the effects of North-of-Delta Offstream X X Storage socioeconomic-climate uncertainties on the CVP South-of-Delta SW or GW X Service Area. As such, the results presented below Storage are for informational purposes only. Enhanced Environmental X Flows Four thematic portfolios of water management Notes: GW = groundwater | M&I = municipal and industrial | actions were analyzed including: SW = surface water

• Portfolio A: Aggressive Local Actions The Local Water Management Actions included • Portfolio C: Delta Conveyance and North- additional conservation measures above the of-Delta Storage Baseline conservation conditions. However, it is important to note that no assessment was made • Portfolio D: Delta Conveyance and South- of whether or not such actions could actually be of-Delta Storage achieved. The Modest Demand Reduction actions • Portfolio E: Aggressive Local Actions, included full implementation of a 20-percent Enhanced Environmental Flows, and North- reduction in urban applied water demand with a of-Delta Storage 5-percent reduction in agricultural applied water (An additional portfolio, Portfolio B focusing on demand to be achieved by 2020 and continue at North-of-Delta Storage was also developed but the same level through 2100. The Aggressive is not included in this summary because those Demand Reduction actions included these actions are included in the composite Portfolios C reductions plus additional water use efficiency and E). The actions that are included in each of measures to achieve a 40-percent reduction in the portfolios are shown in Table 1. urban demand and a 10-percent reduction in agricultural demand by 2050, and a 60-percent

Central Valley Project Integrated Resource Plan Summary Report 27 PERFORMANCE OF POTENTIAL FUTURE WATER MANAGEMENT ACTIONS reduction in urban demand and a 15-percent and water quality benefits to the Delta through reduction in agricultural demand by 2100. outflow augmentation and (3) water supply Municipal Water Recycling was also included in reliability benefits to local users, CVP-SWP water the Local Actions. These supply enhance¬ments contractors and wildlife refuges. were applied only in the San Felipe and Friant Divisions because these are the only Divisions The South-of-Delta Storage Action was simulated that have significant unmet urban demands in to represent potential options for additional surface the Baseline. In the Sacramento River Division, storage, groundwater storage, or conjunctive use 65 TAF of additional municipal recycling and management opportunities within the South- 35 TAF of desalination were assumed to be of-Delta CVP and SWP Service Areas. It was implemented by 2100. In the Friant Division, assumed that new storage would only be filled 100 TAF of municipal recycling was assumed to after existing SWP-CVP San Luis accounts were be implemented by 2100. In both cases, linear full, and that water would be released from this increases were assumed to occur throughout the new South-of-Delta storage prior to releasing 21st century. storage from existing San Luis Reservoir accounts. The assumed maximum simulated storage The System-wide Water Management Actions increases were 972 TAF for the CVP and 1,067 included both changes in infrastructure and TAF for the SWP water contractors. operations. The Enhanced Delta Conveyance Action includes assumptions that were The Enhanced Environmental Flow Action developed solely for the purpose of the CVP IRP provides additional flows beyond existing socioeconomic-climate scenario effects analysis regulatory requirements for improving and do not reflect Reclamation’s policy regarding environmental conditions in the Sacramento the Bay Delta Conservation Plan (BDCP) planning Valley and Delta by requiring additional upstream program. reservoir releases and operational changes including: The Enhanced Delta Conveyance Action assumptions include the following: • Unimpaired flows below Shasta Lake, Lake Oroville, and Folsom Lake are used as • 9,000-cfs capacity Division facility at Hood minimum instream flow requirements. • No minimum South Delta pumping • A Delta outflow requirement of 60 percent • 10,300-cfs Banks PP capacity of total unimpaired flow in each month • Bypass flow controlled by Rio Vista flow from February through June was applied by requirements reducing Delta exports. • Shared SWP and CVP beneficiaries • Offramps based on monthly reservoir storage can be applied to limit the required The Shasta Lake Enlargement Action assumed reservoir releases. a 634 TAF increase in reservoir storage with the primary objectives being to (1) increase survival In the sections below, the results for each of anadromous fish populations in the Sacramento portfolio are compared. To give an overview River upstream of the Red Bluff Diversion Dam; of the range of results associated with the and (2) increase water supply reliability for different socioeconomic-climate scenarios, the agricultural, M&I, and environmental purposes in performance analysis results are shown for the the CVP Service Area. same four socioeconomic-climate scenarios for which unmet demand results were shown above. The North-of-Delta Offstream Storage Action The “Baseline” simulations represent current assumed a 1.8 MAF increase in offstream conditions without any additional management storage in the Sacramento Valley with the actions. primary objectives being (1) provide ecological benefits to the Sacramento River, (2) ecological

28 Central Valley Project Integrated Resource Plan Summary Report PERFORMANCE OF POTENTIAL FUTURE WATER MANAGEMENT ACTIONS

Unmet Demands in the CVP Service conservation with increased storage and enhanced Area Delta conveyance result in significant increases in Delta exports and some reductions in Delta Figure 8 shows the average annual unmet demands outflows whereas the enhanced environmental in thousands of acre-feet per year (TAF/yr) for flows in Portfolio E result in reductions in exports the Baseline and each of four Portfolios using on and increases in outflows. four socioeconomic-climate scenarios selected to characterize the reasonable range of potential For the Baseline and all portfolios, Delta exports future uncertainties during the 21st century. All and outflows in projected central tendency (CT_ four portfolios show significant reductions in Q5) scenario were slightly reduced relative to the unmet demands relative to the Baseline. The no climate change (CT_noCC) scenario. In the largest reductions in unmet demands occur with Baseline as well as all the portfolios, both Delta implementation of the Portfolio “Aggressive” exports and outflow were greatest in the wettest urban and agricultural local water conservation scenario (SG_Q4) and least in the driest scenario and recycling actions. When aggressive (EG_Q2). conservation actions are combined with increased North of Delta storage and enhanced environmental flows (Portfolio E) unmet demand Delta Salinity reductions are slightly less reduced because of The X2 metric is used as a measure of the effect of increased Delta outflows. Although not as large, ocean salinity on Delta water quality. It indicates Portfolios C and D which include only “modest” the location of the 2 parts per thousand salinity demand-reduction actions combined with concentration measured in kilometers (km) from increased storage and enhanced Delta conveyance the Golden Gate Bridge. Larger values indicate also show reductions in unmet demands. increased Delta salinity. Figure 11 shows the The Delta Conveyance - South of Delta storage average simulated X2 positions from February portfolio (D) results in slightly increased unmet to June for the Baseline and portfolios. In all the demands relative to the Delta Conveyance - North socioeconomic-climate change scenarios, the local of Delta storage portfolio (C) largely due to the water demand reductions actions in Portfolio A lessor amount of total storage capacity represented result in very little change in X2 relative to the in the Portfolio D. Baseline conditions. Both of the portfolios with increased storage and enhanced conveyance in (C For all portfolios and the Baseline, projected and D) result in increases in X2 location whereas unmet demands increase under the current trends the enhanced environmental flows in Portfolio E central tendency climate scenario (CT_Q5) decrease the X2 location. relative to the no climate change (CT_noCC) scenario. Even larger increases occur in the For the Baseline and all the portfolios, X2 Expansive Growth and drier climate scenario location increased under the central tendency (EG_Q2) scenario whereas in the Slow Growth socioeconomic-climate scenario (CT_Q5). Even wetter climate scenario (SG_Q4) unmet demands larger X2 increases occur under the drier climate are less than in the no climate change scenario. projection (EG_Q2) whereas in the wetter climate projection (SG_Q4) the X2 position is similar to the no climate change location despite the effects Delta Exports and Outflows of sea level rise in SG_Q4.

Figures 9 and 10 show the average annual Delta exports and outflows in TAF/yr for the Baseline Water Temperature and each portfolio. In all the socioeconomic- climate scenarios, the aggressive local demand- Water temperatures in the Sacramento and San reduction and supply-enhancement actions Joaquin River were simulated for each of the (Portfolio A) result in little change in either portfolios and socioeconomic scenarios. Water exports or outflows relative to Baseline conditions. temperatures in the San Joaquin River were Both Portfolios C and D which combine modest essentially unaffected by any of the Portfolio

Central Valley Project Integrated Resource Plan Summary Report 29 PERFORMANCE OF POTENTIAL FUTURE WATER MANAGEMENT ACTIONS

Figure 8. Average Annual Unmet CVP Demands for each Portfolio and Scenario

Figure 9. Average Annual Total Delta Exports (TAF/yr) for each Portfolio and Scenario.

30 Central Valley Project Integrated Resource Plan Summary Report PERFORMANCE OF POTENTIAL FUTURE WATER MANAGEMENT ACTIONS

Figure 10. Average Annual Delta Outflows (TAF/yr) for each Portfolio and Scenario.

Figure 11. Average Annual February-to-June X2 Locations for each Portfolio and Scenario.

Central Valley Project Integrated Resource Plan Summary Report 31 PERFORMANCE OF POTENTIAL FUTURE WATER MANAGEMENT ACTIONS actions. Changes in mean daily July through are only very slight reductions in hydropower September water temperatures in the Sacramento generation associated with the aggressive local River at Jelly’s Ferry are shown on Figure 12 for demand reduction actions in Portfolio A. The each of the Portfolios. Relative to their Baselines, increased storage and enhanced Delta conveyance the increased North of Delta storage actions in portfolios (C and D) both result in reduced Portfolio C provide the largest reductions in water net hydropower generation and corresponding temperatures. Both the aggressive local demand increases in GHG emissions due to increased reductions actions (Portfolio A) and South of Delta export pumping. Portfolio D has the greatest storage increases (Portfolio D) do provide some net power reductions because of the additional reductions in water temperature at this location. pumping required to store water in the south of Despite including increased North of Delta Delta region. Overall changes are not as large storage, the enhanced environmental flows result for the CVP as for the SWP system because it is in some slight increases in water temperatures. already a net consumer of power in the Baseline. Across the range of socioeconomic-climate The largest decreases in water temperature scenarios, larger increases in generation and occur in the drier climate (EG_Q2) because the reductions in emissions occur in the wetter SG_Q4 additional storage in Portfolio C results in greater scenario than in the drier EG_Q2 scenario with the increases cold water pool relative to the Baseline central tendency (CT_Q5) being intermediate in under drier conditions. The largest increases in magnitude. water temperature occur under the wetter SG_Q5 scenario because increased releases for enhanced environmental flows (Portfolio E) reduce the Economic Benefits cold water pool relative to the Baseline more significantly under these conditions. Urban water supply and salinity costs as well as agricultural economic benefits throughout the CVP Service Area were evaluated to compare Hydropower Generation and the potential effects of changing socioeconomic- Greenhouse Gas Emissions climate conditions on each of portfolios during the early (2025), mid (2055) and late (2085) Figure 13 shows the average annual change in 21st century. It should be clearly noted that net hydropower generation in Gigawatthours the economic benefits reported here are not a per year (GWh/yr) for each portfolio relative to thorough analysis of benefits nor are the costs of their respective Baseline condition. Figure 14 implementing the actions included in the analysis. shows the corresponding changes in mean annual GHG emissions expressed as metric tons of Figure 15 shows the change in average annual carbon dioxide equivalents per year (mtCO2e/yr). benefits in each portfolio relative to their Because hydropower generation essentially occurs Baselines. The largest increases in benefits occur without significant GHG emissions, reductions with the increased storage and enhanced Delta in hydropower may increase the use of fossil fuel conveyance portfolios (C and D). The Portfolio A based power generation resulting in potential aggressive local demand reduction actions show increases in GHG emissions. Since SWP system little effect on economic benefits whereas the produces less power than it uses, any further enhance environmental flows (Portfolio E) results reduction in its power generation is accompanied in decreased benefits. Depending on the portfolio by increased GHG emissions. actions, benefits either increase or decrease continuously during the century. The largest For all the socioeconomic-climate scenarios, changes (both positive or negative) occur in the Portfolio E is the only portfolio that results in Expansive Growth drier climate (EG_Q2) scenario a net increase in hydropower generation. This and the least change occurs in the wetter scenario net increase occurs primarily because there are (SGQ4) reflecting the increased value of water reduced Delta export and conveyance pumping in high growth conditions and reduced supply associated with the enhanced environmental flows availability. for both CVP and SWP systems. This export reduction also reduces GHG emissions. There

32 Central Valley Project Integrated Resource Plan Summary Report PERFORMANCE OF POTENTIAL FUTURE WATER MANAGEMENT ACTIONS

Figure 12. Change in Mean Daily Temperature on Sacramento River at Jelly’s Ferry from July to September for each Portfolio and Scenario Relative to their Baselines.

Figure 13. Change in Net Hydropower Generation in CVP and SWP systems for each Portfolio and Scenario Relative to their Baselines. Central Valley Project Integrated Resource Plan Summary Report 33 PERFORMANCE OF POTENTIAL FUTURE WATER MANAGEMENT ACTIONS

Figure 14. Change in Net GHG emissions in CVP and SWP systems for each Portfolio and Scenario Relative to their Baselines.

34 Central Valley Project Integrated Resource Plan Summary Report PERFORMANCE OF POTENTIAL FUTURE WATER MANAGEMENT ACTIONS

Figure 15. Changes in Average Annual Agricultural and Urban Economic Benefits in the CVP Service Area for each Portfolio and Scenario Relative to their Baselines.

Central Valley Project Integrated Resource Plan Summary Report 35

PORTFOLIO TRADEOFFS

The results of portfolio performance assessments outflow, increased salinity in the Delta, above were compared to evaluate tradeoffs among reduced net hydropower generation, and the portfolios. However, it should be noted that increased GHG emissions. other potentially significant parameters such as • Portfolio D: Delta Conveyance and South- the costs and feasibility of implementing these of-Delta Storage portfolios were not evaluated. ○○ Portfolio D would provide similar benefits and impacts to Portfolio C, • Portfolio A: Aggressive Local Reduction with the exception that smaller water and Supply Enhancements temperature benefits on the upper ○○ Portfolio A would provide reductions Sacramento River would be realized. in unmet demands in the CVP Service Area, with little change in the other • Portfolio E: Aggressive Local Actions, performance metrics as compared to the Enhanced Environmental Flows, and North- Baseline. of-Delta Storage ○○ Portfolio E would provide increases in • Portfolio C: Delta Conveyance and North- Delta outflow, improvements in Delta of-Delta Storage salinity, reductions in unmet demands ○○ Portfolio C would provide increases in the CVP Service Area (though less in Delta exports, reductions in unmet than in Portfolio A), increased net demands in the CVP Service Area hydropower generation, and reduced (though less than in Portfolio A), GHG emissions. These benefits would increased economic benefits, and modest come with reduced Delta exports and improvement in upper Sacramento River reduced economic benefits. water temperatures. However, these benefits would come with reduced Delta

Central Valley Project Integrated Resource Plan Summary Report 37

CVP IRP STUDY LIMITATIONS

The CVP IRP study provides new valuable Cross Valley Canal deliveries or Central information for long-range planning purposes Valley Project Improvement Act (b)(2) regarding the impacts of future climatic and operations. In addition, the model included socioeconomic uncertainties on the CVP Service simplified representations of some of the Area and its Divisions. The CVP IRP study also water management actions as compared to examines the potential benefits and tradeoffs CALSIM II. among several portfolios of water management • Although the analytical approach actions, addressing some identified challenges addressed a broad range of performance confronting the CVP in the 21st century. metrics related to the Central Valley water However, there are limitations that should be kept management system, it did not address some in mind when considering the results of these aspects of California water management that analyses. could be considered important metrics for assessment of impacts and development of • The CVP IRP study is a screening-level robust adaptation strategies. In particular, analysis that simulated the most important the costs of implementing each action were components of the CVP water management not considered in the CVP IRP analysis. system by using simplified representations • The CVP IRP study was only able to of the CVP, SWP, and local project analyze a limited number of potential water operations within the Central Valley. In management actions. This allowed for addition, although the scope of the analysis only a limited assessment of tradeoffs to covered supplies and demands within the be performed among different portfolios of CVP Service Area, the effects of potential actions. Furthermore, no attempt was made actions on SWP and non-project contractor’s to determine which combinations of actions unmet demands were not analyzed. might be optimum with regard to various • The analyses used the WEAP-CV and CVP performance metrics. IRP CalLite models, which are simplified models in which much of the complexity of Despite these limitations, the CVP IRP study the system has been aggregated as compared does provide a solid foundation for future to more complex models such as CALSIM reconnaissance-level analyses of the Central II. CVP IRP CalLite model captured the Valley water management system. The limitations most prominent aspects of the Central described above are intended to identify what Valley hydrology and system operations, but additional improvements in the analytical simulated hydrology and water management approach and modeling tools would benefit within specific sub-basins has limited detail. the Mid Pacific Region’s long range planning Therefore, the model did not simulate activities. some aspects of CVP operations such as

Central Valley Project Integrated Resource Plan Summary Report 39

ACRONYMS AND ABBREVIATIONS USED IN FIGURES

ACRONYMS AND ABBREVIATIONS USED IN FIGURES ∆°C change in temperature in min minimum degrees Centigrade MJ/m2 mega-joules per square meter ∆%P percent change in precipitation mtCO2e/year metric tons of CO2 equivalents Avg average noCC no climate change CT Current Trends CVP Central Valley Project Q1 drier, less warming Q2 drier, more warming EG Expansive Growth Q3 wetter, more warming Q4 wetter, less warming GHG greenhouse gas Q5 ensemble median GW Groundwater GWH/yr Annual Electric Generation in SG Slow Growth Gigawatthours SW surface water SWP State Water Project IRP Integrated Resource Plan TAF thousand acre-feet km kilometer taf/mo thousand acre-feet per month TAF/year thousand acre-feet per year M&I municipal and industrial max maximum

Central Valley Project Integrated Resource Plan Summary Report 41 On the Front Cover: Generic photo of fish with a photo strip showing agriculture, an energy transmission tower, and the Shasta Dam; On the Back Cover: Generic photograph of riparian habitat