CONTRA COSTA WATER DISTRICT. Yield Study Report. for the Refinery Recycled Water Project. May Prepared by: In association with MBK Engineers

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1 CONTRA COSTA WATER DISTRICT Yield Study Report for the Refinery Recycled Water Project Prepared by: In association with MBK Engineers

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3 Yield Study Report for the Refinery Recycled Water Project Prepared by: In association with MBK Engineers May 9, 213

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5 Table of Contents Table of Contents Executive Summary... ES-1 Chapter 1 Introduction... 1 Chapter 2 Background Description of Refinery Project Yield Study Background Delta Conditions... 3 Chapter 3 Modeling Approach Modeling Tools Modeling Methodology and Assumptions... 6 Chapter 4 Project Yield Description of Yield Variability of Yield with Project Size Variability of Yield over Time Chapter 5 Local Benefits Reduction in Third-Party Transfers Increased Storage in Los Vaqueros Reservoir Drought Reliability for Industrial Customers Other Local Benefits Chapter 6 Additional Considerations List of Tables Table 1: Key Modeling Assumptions... 6 Table 2: Water Supply Yield for Refinery Recycled Water Project...11 Table 3: Emergency Storage Benefit from Refinery Recycled Water Project...15 List of Figures Figure 1: Map of Facilities associated with Refinery Project... 2 Figure 2: Frequency of Balanced and Surplus Conditions... 4 Figure 3: Changes in Delta Water Balance for 2-MGD project...1 Figure 4: Water Balance for 5-MGD Project...12 Figure 5: Water Balance for 2-MGD Project...12 Figure 6: Annual Variability in Project Yield...14 Appendices Appendix A: CalSim II Assumptions Appendix B: Yield Study Modeling Results i

6 Table of Contents List of Abbreviations CCCSD CCWD CVP DSM2 mg/l MGD OMR Reclamation SWP TAF/yr Central Contra Costa Sanitary District Contra Costa Water District Central Valley Project Delta Simulation Model II Milligrams/liter Million gallons per day Old and Middle River United States Bureau of Reclamation State Water Project Thousand acre-feet ii

7 Executive Summary Executive Summary Central Contra Costa Sanitary District (CCCSD) is committed to making beneficial use of its water resources through water recycling projects. Towards that end, CCCSD has partnered with the Contra Costa Water District (CCWD) to evaluate the water supply benefit of providing up to 22 thousand acre-feet per year (TAF/yr) or 2 million gallons per day (MGD) of recycled water to two refineries in Martinez for use in cooling towers and as boiler feed water. The Refinery Recycled Water Project (Refinery Project) would replace untreated Delta water, currently provided to the refineries by CCWD via the Contra Costa Canal, with recycled water provided by CCCSD, either directly or through CCWD. In August 211, CCCSD secured a planning grant from the U.S. Bureau of Reclamation (Reclamation) for the preparation of a Title XVI Recycled Water Feasibility Study. A critical piece of information needed for assessing project feasibility is the project s water supply yield, which for this project is defined as the net water supply benefit to CCWD or other users of water in the State. The potential yield for the project was estimated by evaluating the reduction in CCWD Delta diversions that could be used by other customers of exported Delta water, or that provides a direct benefit to CCWD in the form of decreased need for water transfers. This yield depends on a combination of conditions in the Delta, Central Valley Project (CVP) and State Water Project (SWP) operations, and CCWD operations, all of which were simulated with computer modeling to estimate the yield. The modeling approach used to determine Refinery Project yield uses a CalSim II baseline model run provided by Reclamation to provide input to a Delta Simulation Model 2 (DSM2) Delta water quality model; both CalSim II and DSM2 inputs are then input to a model of CCWD s operations called the Los Vaqueros Operations Module. Output from these models was post-processed using a spreadsheet model to determine the size and timing of potential project yield based on Delta conditions, CVP/SWP operations, and export customer demand. Potential Refinery Project yield for Delta exports is limited to periods when the Delta is in balance or when Old and Middle River (OMR) flow criteria are controlling Delta exports. When the Delta is in balance, outflow and exports are operationally managed to meet water quality and flow objectives for the Delta set in State Water Resources Control Board Decision At other times of year, when the Delta is in surplus, excess water is available in the Delta beyond that needed to meet these water quality and flow objectives. Under surplus conditions, the SWP and CVP are exporting as much water as possible, so the project cannot create a water supply benefit for the exporters. When OMR criteria control Delta exports, the SWP and CVP are limiting exports to comply with requirements imposed under the Endangered Species Act for the protection of listed fish species. This yield study finds that the maximum potential Refinery Project yield for SWP and CVP exports is equal to about 5% of recycled water production for both of the project sizes that were considered. For a project size of 5.6 TAF/yr (5 MGD), this is equal to a long-term average yield ES-1

8 Executive Summary of 2.8 TAF/yr. For a project size of 22 TAF/yr (2 MGD), the yield is 11 TAF/yr. The actual project yield will vary between wet years and dry years, with larger yields during dry years. However, project yield will occur in both wet and dry water years, and recycled water production is expected to occur at a constant rate in all water year types. CCWD has sufficient water supply to meet all current and future customer demands. However, the Refinery Project could provide yield to CCWD in the form of reduced reliance on transfers, and in the form of increased storage in Los Vaqueros Reservoir that would be available for local or regional emergency use. Although not a part of the calculated project yield, this emergency drought benefit is equal to an average increase in storage of 4.5 TAF for a project size of 2 MGD. Through this storage, the Refinery Project contributes to the region s emergency storage reliability. The project will also help CCWD meet a mandated 2% reduction in per-capita water use by 22, and benefit receiving water quality by reducing nutrient mass loading from CCCSD s outfall. ES-2

9 Chapter 1 Introduction Chapter 1 Introduction This report summarizes the results of a modeling study conducted to estimate the water supply yield of a project that would deliver up to 22 thousand acre-feet per year (TAF/yr) or 2 million gallons per day (MGD) of recycled water from Central Contra Costa Sanitary District (CCCSD) to refineries in Martinez, California. The modeling studies were conducted by Contra Costa Water District (CCWD) based on a CalSim II baseline model provided by the United States Bureau of Reclamation (Reclamation). The yield estimate is intended to inform discussions about the feasibility of the project and potential funding sources and beneficiaries. 1

10 Chapter 2 Background Chapter 2 Background 2.1 Description of Refinery Project For many years, CCCSD and CCWD have been evaluating the potential for a recycled water project to deliver water to the Tesoro and Shell refineries in Martinez (Refinery Project). In fact, during past severe droughts, tertiary-treated and nitrified effluent has been used by the refineries to conserve Delta water. The Refinery Project deliveries would replace untreated Delta water currently delivered to the refineries by CCWD via the Contra Costa Canal, which is predominantly sourced from the Reclamation s Central Valley Project. The recycled water would be used as cooling tower make-up water and boiler feed water. Key facilities associated with the Refinery Project are shown below in Figure 1. Figure 1: Map of Facilities associated with Refinery Project The Tesoro and Shell refineries are currently served by individual service connections from the CCWD untreated water system. The existing service connection for the Shell refinery is from Martinez Reservoir, while the existing service connection for the Tesoro refinery is from a lateral pipeline connecting eastward to the Contra Costa Canal (blue, Figure 1). Under the Refinery Project, these service connections would be replaced by connections to an existing CCWD pipeline and two existing CCWD tanks, which in turn connect to a recycled water distribution 2

11 Chapter 2 Background pipeline owned by CCCSD (purple, Figure 1). The Refinery Project would also involve construction of new recycled water treatment facilities at CCCSD s existing wastewater treatment plant site, including ammonia removal, filtration, and disinfection. 2.2 Yield Study Background In August 211, CCCSD secured a planning grant from Reclamation for the preparation of a Title XVI Recycled Water Feasibility Study. A critical piece of information needed for this feasibility study is the project s water supply yield. CCCSD and CCWD have partnered in this Refinery Recycled Water Project Yield Study effort to estimate the potential water supply yield and the resulting benefits to the recycled water supply portfolio. Because of CCWD s location and how it withdraws, stores, and delivers water from the Delta, the water supply yield of the Refinery Project is not simply equal to the amount of water delivered to the refineries. Instead, the yield depends on a combination of conditions in the Delta, Central Valley Project (CVP) and State Water Project (SWP) operations, and CCWD operations. This entire system can be simulated with computer modeling to estimate the yield. 2.3 Delta Conditions The Refinery Project s ability to create water supply benefits for CCWD or other Delta water users depends on conditions in the Delta when CCWD operations are proposed to be changed. Delta conditions fall into one of two categories: balanced and surplus, as described below. Also, Delta exports can be restricted by Old and Middle River (OMR) flow criteria from December to June while the Delta is in either balanced or surplus conditions Yield under Balanced Conditions Delta balanced conditions exist when upstream reservoir releases plus unregulated flows are approximately equal to the sum of exports, Sacramento Valley in-basin uses (including Delta consumptive uses), and water needed to meet Delta salinity and flow standards. The resulting Delta outflow is equal to the required outflow. Delta Outflow Required Delta Outflow Delta balanced conditions typically occur June through November, as shown below in Figure 2. 3

12 Chapter 2 Background Figure 2: Frequency of Balanced and Surplus Conditions Balanced Delta Condition Surplus Delta Condition 1% Average Frequency by Month 8% 6% 4% 2% % Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep The occurrence of Delta balanced and surplus conditions shown above is based on the 82-year hydrology from the CalSim II baseline study used in this yield study, and described in greater detail in Chapters 3 and 4. Reductions in CCWD diversions due to the Refinery Project that were to occur during Delta balanced conditions could potentially create a water supply benefit for CCWD or other Delta water users, as discussed in Chapter 4. This yield is limited to periods when there is a reduction in CCWD diversions AND there is either export capacity to export that water immediately, or available upstream storage for water that can subsequently be delivered, not spilled The use of upstream storage is discussed in greater detail in Chapter Yield under Delta Surplus Conditions Delta surplus conditions exist when excess water is available in the Delta beyond what is needed to meet the D1641 Delta water quality and flow standards and what is being diverted by in-basin users, the CVP, and State Water Project (SWP). Delta Outflow Required Delta Outflow Under surplus conditions, there is either no unmet water demand, or insufficient pumping and conveyance capacity to deliver the water to Delta export customers. Therefore, there cannot be 4

13 Chapter 3 Modeling Approach any project yield to exporters during Delta surplus conditions, except under the distinct scenario described below. There is also no yield to CCWD under Delta surplus conditions Old and Middle River Flow Criteria When OMR flow criteria are controlling Delta exports and the recycled water project output allows for CCWD Delta diversion reductions at its Old River or Victoria Canal Intakes, there is a potential for project yield. (When CCWD is meeting demand by direct diversion from the Rock Slough Intake, diversion reductions do not affect OMR.) This scenario can occur under either balanced or surplus conditions. As currently formulated in CalSim II, the reduction in diversions at the Old River or Victoria Canal intakes will result in an increase in OMR flow, which, in turn, relaxes the OMR control on Banks and Jones Pumping Plants, thereby allowing greater Delta exports. This water supply benefit was included in the calculation of total project yield. Note that if the current proposal by Reclamation and CCWD to change OMR compliance to be measured by an index that does not include CCWD diversions 1 is adopted by the regulatory agencies, this scenario will no longer provide an opportunity for project yield. Also, the beneficiary of project yield whether CCWD or other Delta exporters could vary based on possible changes to the SWP-CVP or Reclamation-CCWD Coordinated Operations Agreements. Chapter 3 Modeling Approach 3.1 Modeling Tools The yield study utilized CalSim II in combination with CCWD s Los Vaqueros Module to simulate CCWD operations. Output from these models was post-processed using a spreadsheet model to determine the size and timing of project yield. Calsim II Baseline Los Vaqueros Operations Module Exports and Storage Postprocessor Project Yield Each of these tools is described below in greater detail. CalSim II - CalSim II is a planning model used to simulate CVP and SWP operations. The model has a monthly time-step and uses an 82-yr historical hydrologic record. The model includes the Delta and the CVP and SWP systems, including upstream reservoirs and Delta export facilities. The CalSim II baseline simulation results were input to the Delta Simulation Model II (DSM2) to provide Delta water quality inputs for the Los Vaqueros Module described below. 1 For details, see 5

14 Chapter 3 Modeling Approach Los Vaqueros Module The Los Vaqueros Module simulates CCWD operations, including Delta intake and Los Vaqueros storage operations. CCWD uses Los Vaqueros Reservoir as a water quality reservoir, storing water when Delta salinity is low (often during Delta surplus conditions) and releasing water for customer delivery when Delta salinity is above CCWD s delivery goals. The Module includes algorithms for meeting CCWD water supply and water quality targets. For the yield study, the Module was run as a stand-alone model using output from CalSim II and DSM2 to define conditions affecting CCWD Delta diversions. Post-processor The post-processor is a custom spreadsheet model that combines the results of the Los Vaqueros Operations Module output with the CalSim II baseline operations to simulate with-project operations. The post-processor tool produces results that are more realistic and easier to interpret than a CalSim II run. This is because the changes in flows associated with the Refinery Project are small relative to overall Delta flows, and CalSim is not well-suited to simulating operational changes resulting from such small changes. Any potential effects on Delta conditions caused by reductions in CCCSD treated water discharges (in particular, those due to a corresponding reduction in Delta outflow) were not analyzed in the yield study. 3.2 Modeling Methodology and Assumptions The approach used to model project yield was to post-process an existing CalSim II baseline run based on simulated changes in CCWD operations resulting from reducing CCWD raw water demands consistent with recycled water production from the Refinery Project. A key assumption of the yield study modeling is that project yield is equal to the difference in CVP/SWP Delta exports between a with-project scenario and the no-project scenario. The no-project scenario comes directly from the CalSim II baseline run and Los Vaqueros module only, while the with-project scenario was quantified using the post-processor. No other changes to infrastructure, water rights, or water demands were incorporated into the modeled scenarios. This assumption precludes the possibility of CCWD storing and/or delivering water outside of its existing service area to produce project yield, since such transfers are not possible under existing infrastructure and water rights. Other key assumptions are documented below in Table 1. Table 1: Key Modeling Assumptions Parameter Refinery Recycled Water Deliveries Modeling Assumption 5 MGD / 5.6 TAF/yr, or 2 MGD / 22 TAF/yr Demand is constant year-round CCWD Demand Current (211) CalSim II Baseline January 212 Baseline, Existing Condition, Provided by Reclamation 6

15 Chapter 3 Modeling Approach CalSim II Baseline Assumptions The CalSim II baseline run selected for use in this project was provided by Reclamation 2 as the current best available tool for CVP and SWP planning studies. A detailed list of model assumptions about hydrology, demands, facilities, regulatory standards, operations criteria, and water transfers used in the baseline run are listed in Appendix A. The selected baseline run was produced by Reclamation in January 212 and was based on CalSim II model runs originally created in support of the Bay Delta Conservation Plan. Notable assumptions in the baseline run include the following: Demands in the San Joaquin River Basin reflect the full amount of 155 TAF/year for Stockton East Water District. A 4-cfs intertie between the Delta-Mendota Canal and California Aqueduct is included. The storage capacity of Los Vaqueros Reservoir is 16 TAF. Implementation of CCWD s Alternative Intake Project at Victoria Canal (now called the Middle River Intake) is included. Export restrictions from the experimental flow program referred to as the Vernalis Adaptive Management Plan (VAMP) are not included. The model includes Interim San Joaquin River Restoration flows. OMR flow criteria reflect the NMFS Biological Opinion for salmon and U.S. Fish and Wildlife Service Biological Opinions for smelt. Current level of development and Delta operations were simulated, as listed in Appendix A. There are future changes in the Delta that could affect the project yield and costs of the Refinery Project for example, Delta balanced conditions could become more frequent but these possible changes were not included in the modeled scenarios. These factors include climate change, future regulations and changes in interpretation of the biological opinions for the SWP/CVP Operations Criteria and Plan, changes to the SWP-CVP or Reclamation-CCWD Coordinated Operations Agreements, minimum flow requirements in the Delta, and implementation of the Bay Delta Conservation Plan. Likewise, implementation of the Bay Area Regional Desalination Project was not included in the simulation. Delta Salinity Included with the baseline output is Delta salinity data at CCWD s Rock Slough, Old River, and Victoria Canal intakes. This salinity data affects the Delta diversion decisions in the Los Vaqueros Module, and is therefore necessary input to that module. The Delta salinity data is output from DSM2, which uses the CalSim II baseline for boundary condition input. 2 CalSim II Baseline provided by Tom FitzHugh, Water Resources Modeler, U.S. Bureau of Reclamation Mid- Pacific Region, on August 23,

16 Chapter 3 Modeling Approach Los Vaqueros Module Using the baseline Delta hydrology and salinity from CalSim II and DSM2, the stand-alone Los Vaqueros Module was run for without-project conditions, for a 5-MGD reduction in CCWD demands year round, and for a 2-MGD reduction in CCWD demands year round. The Module predicts CCWD diversions from the Delta on a monthly time step, as well as determining when third-party transfers would be required to meet CCWD customer demand. Current (211) CCWD demands were used. The Los Vaqueros Operations Module simulates higher customer demands and lower CVP contract allocation in dry years, resulting in an infrequent need for a small volume of third-party transfers to CCWD under these conditions. Post-Processor to Determine Yield Finally, the post-processor tool was used to determine potential changes in CVP / SWP and Delta operations due to changes in CCWD operations. Reductions in CCWD diversions can create project yield only under either (a) balanced Delta conditions or (b) surplus Delta conditions with OMR flow criteria controlling exports. Also, the post-processor counts the reduced diversions as project yield only if there is export capacity available based on a review of the CalSim II output, or if there is available upstream storage in Shasta Reservoir or Folsom Reservoir that can subsequently be delivered to downstream users. This determination was made using CalSim II output. Availability of export capacity was quantified by comparing baseline exports at the Banks and Jones Pumping Plants to physical pumping capacity constraints, permit constraints, and regulatory constraints. Examples of regulatory constraints on exports include the maximum allowable export-to-inflow ratios listed in State Water Resources Control Board Decision 1641 (D-1641), the minimum allowable San Joaquin River inflow-to-export ratio specified in the National Marine Fisheries Service (NMFS) Biological Opinion for salmon, and the OMR flow criteria specified in both the NMFS Biological Opinion for salmon and U.S. Fish and Wildlife Service Biological Opinions for smelt. Capacity to distribute additional yield South-of-Delta was further limited by available storage capacity in San Luis Reservoir. The ability to store undiverted water in Shasta or Folsom Reservoirs for subsequent export was dependent on the particular constraints to releases from each reservoir. If the reservoir was releasing for flood control purposes, or to maintain downstream minimum flow requirements, water could not be backed into that reservoir. However, if the reservoir was releasing specifically to support exports above the needs of public health and safety, then a window of opportunity to back recycled water output into Shasta or Folsom exists. The post-processor uses these opportunities to moderately increase project yield. 8

17 Chapter 4 Project Yield Chapter 4 Project Yield 4.1 Description of Yield With the refineries served by CCCSD recycled water rather than CCWD untreated water, CCWD could reduce its diversions from the Delta. Project yield is defined as the reduction in diversions by CCWD that reduces CCWD s need for transfer water or that can subsequently be re-routed to other CVP/SWP export customers. This re-routing can only occur when there is sufficient demand AND export capacity. If there is not sufficient export capacity at the time of reduced CCWD diversions, the water can sometimes be stored in Shasta or Folsom Reservoirs until the next available export opportunity; only water that is eventually exported, not spilled, contributes to project yield. Reclamation noted during initial discussions for the yield study that other operational constraints (such as releases for temperature control and the Coordinated Operations Agreement) may limit the ability of Reclamation to back water up in storage, and the small volumes involved in this project would further limit Reclamation s ability to alter operations in response to changed flows. Therefore, the yield analysis presented in this study represents the maximum potential yield the project could provide from a Reclamation operations perspective. The reduction in total CCWD diversions is approximately equal to the recycled water production rate, but not all of the reduced CCWD diversions are CVP water. A small portion of the modeled reduction is 3 rd party transfer water rather than CVP contract water. This reduction in transfer water to CCWD is a component of project yield, as noted above. A similarly small portion of the modeled reduction falls under CCWD s Los Vaqueros water right, which is only diverted under Delta surplus conditions. Changes in this diversion do not contribute to project yield. Changes in the Delta water balance related to project yield are illustrated below in Figure 3. 9

18 Chapter 4 Project Yield Figure 3: Changes in Delta Water Balance for 2-MGD project Over the long term, the 2-MGD (22 TAF/yr) project is anticipated to reduce CCWD s CVP diversions by 21 TAF/yr, and reduce predicted third-party transfers to CCWD by.7 TAF/yr. The project yield is expected to be about 51% of recycled water production for the 5-MGD (5.6 TAF/yr) project, or 49% of recycled water production for the 2 MGD (22 TAF/yr) project. This is equal to a long-term average yield of 2.8 TAF/yr for the 5-MGD project, or 11 TAF/yr for the 2-MGD project, as shown below in Table 2. 1

19 Chapter 4 Project Yield Table 2: Water Supply Yield for Refinery Recycled Water Project 5 MGD Project 2 MGD Project Percent of Longrecycled Term water Average production (TAF/year) Long- Term Average (TAF/year) Percent of recycled water production CCCSD Recycled Water Production Reduction in Total CCWD Diversions % 22 99% Reduction in CCWD CVP Diversions % 21 94% Yield from Reduction in Third-party Transfers to CCWD.3 6%.7 3% Yield from Increase in Direct Exports % % Yield from Reoperation of Shasta.5 9% 2. 9% Yield from Reoperation of Folsom.1 2%.6 2% Total Yield % 11 49% Increased outflow % 11 51% Notes: 1. Increased outflow is calculated as the (Reduction in Total CCWD Diversions) less the (Total Yield). All volumes are rounded two significant figures. The long-term average of 21 TAF/yr in reduced CVP diversions for the 2-MGD project changes the Delta water balance in two main ways: Delta outflows increase by 11 TAF/yr, primarily during surplus conditions, and exports to other CVP/SWP customers increase by 1 TAF. Out of this 1 TAF/yr of increased exports, 2.6 TAF/yr are dependent on use of storage in Shasta or Folsom Reservoirs to optimize exports. Similar trends apply to the 5-MGD project, but on a smaller scale. This anticipated water balance for the 5-MGD project, including the contributions to project yield increased Delta outflows, is shown below in Figure 4. A similar water balance for the 2-MGD project is shown in Figure 5. 11

20 Chapter 4 Project Yield Figure 4: Water Balance for 5-MGD Project Figure 5: Water Balance for 2-MGD Project 4.2 Variability of Yield with Project Size As shown above in Table 2, the changes in the Delta water balance scale directly in proportion to the size of the project. For a 5-MGD (5.6 TAF/yr) recycled water production rate, the project yield is 51% of the recycled water production. This proportion of project yield to recycled water production rate is nearly identical to the 49% yield projected for the 2-MGD project. 4.3 Variability of Yield over Time The project yield discussed above is a long-term average, but there will also be significant variability between wet and dry years. In wet years, there tends to be very little capacity available at the export pumps or in Shasta Reservoir, so wet years contribute less towards the project yield. In fact, project yield is expected to be about 5% greater in dry or critically dry water years. Nonetheless, recycled water production was assumed to occur at a constant rate in 12

21 Chapter 4 Project Yield all water year types, since operating only in dry years would substantially decrease the overall project yield. For the 2-MGD project, the variation of project yield over 1 of the 82 years of historical hydrology available in CalSim II is shown on the next page in Figure 6. As indicated in the figure, there is very little yield in a wet periods such as water years By contrast, project yield reaches a peak value in a critically dry period like water year Appendix B contains figures showing model output for the 2-MGD project for all 82 years of historical hydrology available in CalSim II. 13

22 Chapter 4 Project Yield Figure 6: Annual Variability in Project Yield Flow (1, AF) Available Export Capacity Change in CCWD CVP Diversion Increase in Delta Exports Reduced Transfers to CCWD Recycled Water -2 1/1974 1/1975 1/1976 1/1977 1/ Available Export Capacity Increase in Delta Exports Recycled Water Flow (1, AF) Change in CCWD CVP Diversion -2 1/1979 1/198 1/1981 1/1982 1/1983 Direct Increased Exports Increased Exports from Folsom Release Increased Exports from Shasta Release Reduced Transfers to CCWD Change in CCWD CVP Diversion Available Export Capacity Recycled Water Production 14

23 Chapter 5 Local Benefits Chapter 5 Local Benefits Local benefits to CCWD and its customers include those that are quantified as part of project yield, like the reduction in third-party transfers, as well as other related benefits. This section describes these benefits in greater detail. 5.1 Reduction in Third-Party Transfers The Refinery Recycled Water Project would reduce CCWD s need to obtain water via thirdparty transfers under drought conditions. The average reduction in third-party transfers to CCWD is.7 TAF/year for the 2-MGD project, as shown above in Table 2. These reductions are expected to occur towards the end or immediately following drought periods for example, in early 1978, following the critically dry year of 1977 (see purple bars in Figure 6, above). Reductions in third-party transfers represent a potential cost savings for CCWD. Modeled reductions in third-party transfers to CCWD over the entire 82 years of historical hydrology available in CalSim II are shown in Figure B-2 of Appendix B. 5.2 Increased Storage in Los Vaqueros Reservoir The Refinery Recycled Water Project is anticipated to produce a small increase in the average annual storage in Los Vaqueros Reservoir. This increase in storage is not a component of project yield, since CCWD is not supply-limited and the primary purpose of Los Vaqueros Reservoir is improving water quality rather than water supply. However, it does provide a benefit to the region s emergency water storage. This benefit would occur under both the 5-MGD and 2- MGD projects, as shown below in Table 3. Table 3: Emergency Storage Benefit from Refinery Recycled Water Project Baseline 5 MGD Project 2 MGD Project Annual Average Storage in Los Vaqueros Reservoir 12.2 TAF TAF TAF Increase in Annual Average Storage compared to Baseline - 1. TAF 4.5 TAF The project would also improve CCWD delivered water quality by very slightly increasing the fraction of the time that CCWD meets its goal of 65 mg/l of chloride for delivered water, from 89% to 9% under either the 5-MGD or 2-MGD project. 5.3 Drought Reliability for Industrial Customers CCWD s maintains high drought reliability for customers, with an estimated 85% reliability system-wide and 95% reliability for industrial customers. This means that industrial customers like the refineries could be subject to water use cutbacks of approximately 5% under severe drought conditions. The Refinery Recycled Water Project could provide water during such 15

24 Chapter 5 Local Benefits drought periods, thereby providing a small but real increase in the drought reliability of the refineries water supply. 5.4 Other Local Benefits The project would assist CCWD achieve the mandated 2% reduction in per capita water use by 22, as required by the Water Conservation Act of 29 (SB X7-7). The project would help CCWD avoid some capital and variable O&M expenditures associated with conveyance of untreated water. However, requirements for back-up supply, if required, would limit the benefit to CCWD by requiring a reservation of capacity in CCWD s untreated water conveyance system. The project would diversify CCWD s water supply portfolio and could reduce its vulnerability to climate change, to the extent that the water supply reliability of the Delta may be reduced by climate change impacts. 16

25 Chapter 6 Additional Considerations Chapter 6 Additional Considerations The focus of this yield study was quantifying project yield, but there are other potential project benefits and impacts would be considered as part of the more comprehensive Title XVI Feasibility Study. Additional project considerations to be addressed in the Title XVI Feasibility Study would include the following: The project may enhance Delta water quality by reducing nutrient mass loading from CCCSD s outfall. This reduction will be estimated and discussed in greater detail in the Feasibility Study. The Feasibility Study will include a comparison of the costs and benefits of the project to other water supply alternatives, such as conservation and water transfers. The Feasibility Study will address the technical feasibility and costs of using recycled water at the refineries, and in particular in the boiler feed systems.. The Feasibility Study will address the extent to which providing recycled water directly to a customer, rather than returning water to Suisun Bay to become part of Delta outflow or exporting it from a different location, is a net beneficial use. The energy use and greenhouse gas impacts of the embedded energy in raw water versus recycled water, changed refinery operations, and increased exports will be considered. 17

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27 Appendix A - CalSim II Assumptions

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29 Appendix A: CalSim II Assumptions The Yield Study used a CalSim II baseline scenario corresponding to the Existing Condition column shown in Table A-1, below. The table was provided by provided by Tom FitzHugh, Water Resources Modeler, U.S. Bureau of Reclamation Mid-Pacific Region, on August 23, 212, and is presented here without any modification of the content. Table A-1: CalSim-II Assumptions for U.S. Bureau of Reclamation January 212 Baselines Existing Condition 1 Future Condition 1 Planning Horizon Period of Simulation 82 years ( ) HYDROLOGY Level of Development (land use) 25 Level 2 23 Level 3 DEMANDS North of Delta (excluding the American River) CVP Land-use based, limited by contract amounts 4 Land-use based, full build-out of contract amounts SWP (FRSA) Land-use based, limited by contract amounts 5 Nonproject Land-use based, limited by water rights and SWRCB Decisions for Existing Facilities Antioch Water Works Pre-1914 water right Federal refuges Recent historical Level 2 water needs 6 Firm Level 2 water needs 6 American River Basin Water rights Year 25 7 Year 225, full water rights 7 CVP Year 25 7 Year 225, full contracts, including Freeport Regional Water Project 7 San Joaquin River Basin 9 Friant Unit Lower basin 1 19 Stanislaus River basin Land-use Limited by contract amounts, based on current allocation policy Land-use based, based on district level operations and constraints based, based on New Melones Interim Operations Plan, up to full SEWD deliveries (155 TAF/yr) depending on New Melones Index South of Delta CVP Demand based on contract amounts 4 Federal refuges Recent historical Level 2 water needs 6 Firm Level 2 water needs 6 CCWD 195 TAF/yr CVP contract supply and water 11 rights 11 SWP 5 12 Variable demand, of MAF/Yr, up to Demand based on full Table A Table A amounts including all Table A amounts transfers through 28 Article 56 Based on contractor requests A-1

30 Appendix A: CalSim II Assumptions Existing Condition 1 Future Condition 1 Article 21 North Bay Aqueduct FACILITIES MWD demand up to 2 TAF/month from December to March subject to conveyance capacity, KCWA demand up to 18 TAF/month and other contractor demands up to 34 TAF/month in all months, subject to conveyance capacity. 71 TAF/yr demand under SWP contracts, up to 43.7 cfs of excess flow under Fairfield, Vacaville and Benecia Settlement Agreement System-Wide Existing facilities Sacramento Valley Shasta Lake Existing, 4,552 TAF capacity Red Bluff Diversion Dam Diversion dam operated gates out, except Diversion dam operated with Jun 15 th Aug 31 st based on NMFS BO gates out all year, NMFS BO (Jun 29) Action I ; assume (Jun 29) Action I ; interim/temporary facilities in place assume permanent facilities in place Colusa Basin Existing conveyance and storage facilities Upper American River PCWA American River pump station Lower Sacramento River None Freeport Regional Water Project Delta Export Conveyance SWP Banks Pumping Plant (South Delta) CVP C.W. Bill Jones Pumping Plant (formerly Tracy PP) Upper Delta-Mendota Canal Capacity Los Vaqueros Reservoir Physical capacity is 1,3 cfs but 6,68 cfs permitted capacity in all months up to 8,5 cfs during Dec 15 th - Mar 15 th depending on Vernalis flow conditions 2 ; additional capacity of 5 cfs (up to 7,18 cfs) allowed for for reducing impact of NMFS BO (Jun 29) Action IV on SWP 21 Permit capacity is 4,6 cfs in all months (allowed for by the Delta-Mendota Canal- California Aqueduct Intertie) Existing (exports limited to 4,2 cfs plus diversion upstream from DMC constriction) plus 4 cfs Delta-Mendota Canal-California Aqueduct Intertie Enlarged storage capacity, 16 TAF, existing pump location. Alternate Intake Project included 14 Enlarged storage capacity, 16 TAF, existing pump location. Alternate Intake Project included 14 San Joaquin River Millerton Lake (Friant Dam) Existing, 52 TAF capacity Lower San Joaquin River None City of Stockton Delta Water Supply Project, 3 mgd capacity South of Delta (CVP/SWP project facilities) South Bay Aqueduct Existing capacity SBA rehabilitation, 43 cfs capacity from junction with California Aqueduct to Alameda County FC&WSD Zone 7 point A-2

31 Appendix A: CalSim II Assumptions Existing Condition 1 Future Condition 1 California Aqueduct East Branch Existing capacity REGULATORY STANDARDS Trinity River Minimum Flow below Lewiston Dam Trinity Reservoir end-of- September minimum storage Clear Creek Minimum flow below Whiskeytown Dam Trinity EIS Preferred Alternative ( TAF/yr) Trinity EIS Preferred Alternative (6 TAF as able) Downstream water rights, 1963 Reclamation proposal to USFWS and NPS, and USFWS predetermined CVPIA 346(b)(2) flows 22, and NMFS BO (Jun 29) Action I Upper Sacramento River Shasta Lake end-of-september minimum storage NMFS 24 Winter-run Biological Opinion (19 TAF in non-critical dry years), and NMFS BO (Jun 29) Action I Minimum flow below Keswick Dam SWRCB WR 9-5, predetermined CVPIA 346(b)(2) flows, and NMFS BO (Jun 29) Action I Feather River Minimum flow below Thermalito 26 Settlement Agreement (7 / 8 cfs). Diversion Dam Minimum flow below Thermalito Afterbay outlet Yuba River Minimum flow below Daguerre Point Dam 1983 DWR, DFG agreement (75 1,7 cfs) D-1644 Operations (Lower Yuba River Accord) 15 American River Minimum flow below Nimbus Dam American River Flow Management as required by NMFS BO (Jun 29) Action II.1 19 Minimum flow at H Street Bridge SWRCB D-893 Lower Sacramento River Minimum flow near Rio Vista SWRCB D-1641 Mokelumne River Minimum flow below Camanche Dam Minimum flow below Woodbridge Diversion Dam Stanislaus River Minimum flow below Goodwin Dam FERC , 1996 (Joint Settlement Agreement) (1 325 cfs) FERC , 1996 (Joint Settlement Agreement) (25 3 cfs) 1987 Reclamation, DFG agreement, and flows required for NMFS BO (Jun 29) Action III.1.2 and III Minimum dissolved oxygen SWRCB D-1422 Merced River Minimum flow below Crocker- Huffman Diversion Dam Davis-Grunsky (18 22 cfs, Nov Mar), and Cowell Agreement A-3

32 Appendix A: CalSim II Assumptions Existing Condition 1 Future Condition 1 Minimum flow at Shaffer Bridge FERC 2179 (25 1 cfs) Tuolumne River Minimum flow at Lagrange Bridge FERC , 1995 (Settlement Agreement) (94 31 TAF/yr) San Joaquin River San Joaquin River below Friant Dam/Mendota Pool Interim San Joaquin River Restoration flows Full San Joaquin River Restoration flows Maximum salinity near Vernalis SWRCB D-1641 Minimum flow near Vernalis SWRCB D-1641 but with Vernalis Adaptive SWRCB D-1641 and Vernalis Management Plan single-step standard only, Adaptive Management Plan per per purchase agreement between Reclamation and Merced ID. NMFS BO (Jun 29) Action IV.2.1 Phase II flows not provided due to lack of agreement for purchasing water. San Joaquin River Agreement. 17 NMFS BO (Jun 29) Action IV.2.1 Phase II flows not provided due to lack of agreement for purchasing water. Sacramento-San Joaquin Delta Delta Outflow Index (flow and salinity) Delta Cross Channel gate operation South Delta exports (Jones PP and Banks PP) Combined Flow in Old and Middle River (OMR) OPERATIONS CRITERIA: RIVER-SPECIFIC Upper Sacramento River Flow objective for navigation (Wilkins Slough) American River Folsom Dam flood control Feather River Flow at mouth of Feather River (above Verona) Stanislaus River Flow below Goodwin Dam San Joaquin River SWRCB D-1641 and FWS BO (Dec 28) Action 4 19 SWRCB D-1641 with additional days closed from Oct 1-Jan 31 based on NMFS BO (Jun 29) Action IV (closed during flushing flows from Oct 1-Dec 14 unless adverse water quality conditions) SWRCB D-1641 not including VAMP period export cap under the San Joaquin River Agreement, Vernalis flow-based export limits in Apr -May as required by NMFS BO (June 29) Action IV.2.1 Phase II 19 (additional 5 cfs allowed for Jul-Sep for reducing impact on SWP) 21 FWS BO (Dec 28) Actions 1, 2, and 3 and NMFS BO (Jun 29) Action IV NMFS BO (Jun 29) Action I.4 19 ; 3,5 5, cfs based on CVP water supply condition Variable 4/67 flood control diagram (without outlet modifications) Maintain DFG/DWR flow target of 2,8 cfs for Apr - Sep dependent on Oroville inflow and FRSA allocation Revised Operations Plan and NMFS BO (Jun 29) Action III.1.2 and III A-4

33 Appendix A: CalSim II Assumptions Salinity at Vernalis Grasslands Bypass Project (partial implementation) OPERATIONS CRITERIA: SYSTEMWIDE CVP Water Allocation Existing Condition 1 Future Condition 1 CVP settlement and exchange 1% (75% in Shasta critical years) CVP refuges 1% (75% in Shasta critical years) CVP agriculture 1% - % based on supply. South-of-Delta allocations are additionally limited due to D-1641, FWS BO (Dec 28), and NMFS BO (Jun 29) 19 CVP municipal & industrial 1% - 5% based on supply. South-of- Delta allocations are additionally limited due to D-1641, FWS BO (Dec 28), and NMFS BO (Jun 29) 19 SWP Water Allocation North of Delta (FRSA) Contract-specific South of Delta (including North Bay Aqueduct) Based on supply; equal prioritization between Ag and M&I based on Monterey Agreement; allocations are limited due to D- 1641, FWS BO (Dec 28), and NMFS BO (Jun 29) 19 CVP/SWP Coordinated Operations Sharing of responsibility for inbasin use 1986 Coordinated Operations Agreement (FRWP and EBMUD 2/3 of the North Bay Aqueduct diversions are considered as Delta export, 1/3 of the North Bay Aqueduct diversion is considered as in-basin use) Sharing of surplus flows 1986 Coordinated Operations Agreement Sharing of restricted export Equal sharing of export capacity under capacity for project-specific priority SWRCB D-1641, FWS BO (Dec 28), and pumping NMFS BO (Jun 29) export restrictions 19 Water transfers Acquisitions by SWP contractors are wheeled at priority in Banks Pumping Plant over non-swp users; LYRA included for SWP contractors 21 Sharing of export capacity for lesser priority and wheelingrelated pumping San Luis Reservoir CVPIA 346(b)(2) Policy decision Allocation Cross Valley Canal wheeling (max of 128 TAF/yr), CALFED ROD defined Joint Point of Diversion (JPOD) San Luis Reservoir is allowed to operate to a minimum storage of 1 TAF Per May 23 Department of Interior decision 8 TAF/yr, 7 TAF/yr in dry years, and 6 TAF/yr in critical years Grasslands Bypass Project (full implementation) A-5

34 Appendix A: CalSim II Assumptions Existing Condition 1 Future Condition 1 Actions Pre-determined non-discretionary FWS BO (Dec 28) upstream fish flow objectives (Oct-Jan) for Clear Creek and Keswick Dam, non-discretionary NMFS BO (Jun 29) actions for the American and Stanislaus Rivers, and NMFS BO (Jun 29) actions leading to export restrictions 19 Accounting adjustments No discretion assumed under FWS BO (Dec 28) and NMFS BO (Jun 29) 19, no accounting WATER MANAGEMENT ACTIONS Water Transfer Supplies (long term programs) Lower Yuba River Accord 21 Yuba River acquisitions for reducing impact of NMFS BO export restrictions 19 on SWP Phase 8 None None Water Transfers (short term or temporary programs) Sacramento Valley acquisitions conveyed through Banks PP Post analysis of available capacity Notes: 1 These assumptions have been developed under the direction of the Department of Water Resources and Bureau of Reclamation management team for the Bay Delta Conservation Plan (BDCP) HCP and EIR/EIS. Additional modifications were made by Reclamation for its Jan 212 baselines. 2 The Sacramento Valley hydrology used in the Existing Condition CalSim-II model reflects nominal 25 land-use assumptions. The nominal 25 land use was determined by interpolation between the 1995 and projected 22 land-use assumptions associated with DWR Bulletin (1998). The San Joaquin Valley hydrology reflects 25 land-use assumptions developed by Reclamation to support Reclamation studies. 3 The Sacramento Valley hydrology used in the Future Condition CalSim-II model reflects 22 land-use assumptions associated with Bulletin The San Joaquin Valley hydrology reflects draft 23 land-use assumptions developed by Reclamation to support Reclamation studies. 4 CVP contract amounts have been reviewed and updated according to existing and amended contracts, as appropriate. Assumptions regarding CVP agricultural and M&I service contracts and Settlement Contract amounts are documented in the Delivery Specifications attachments to the BDCP CalSim assumptions document. 5 SWP contract amounts have been updated as appropriate based on recent Table A transfers/agreements. Assumptions regarding SWP agricultural and M&I contract amounts are documented in the Delivery Specifications attachments to the BDCP CalSim assumptions document. 6 Water needs for Federal refuges have been reviewed and updated, as appropriate. Assumptions regarding firm Level 2 refuge water needs are documented in the Delivery Specifications attachments to the BDCP CalSim assumptions document. Refuge Level 4 (and incremental Level 4) water is not included. 7 Assumptions regarding American River water rights and CVP contracts are documented in the Delivery Specifications attachments to the BDCP CalSim assumptions document. The Sacramento Area Water Forum agreement, its dry year diversion reductions, Middle Fork Project operations and mitigation water is not included. 8 Footnote removed. 9 The new CalSim-II representation of the San Joaquin River has been included in this model package (CalSim-II San Joaquin River Model, Reclamation, 25). Updates to the San Joaquin River have been included since the preliminary model release in August 25. The model reflects the difficulties of on-going groundwater overdraft problems. The 23 level of development representation of the San Joaquin River Basin does not make any attempt to offer solutions to groundwater overdraft problems. In addition a dynamic groundwater simulation is not yet developed for the San Joaquin River Valley. Groundwater extraction/ recharge and stream-groundwater interaction are static assumptions and may not accurately reflect a response to simulated actions. These limitations should be considered in the analysis of result 1 The CALSIM II model representation for the Stanislaus River does not necessarily represent Reclamation s current or future operational policies. A suitable plan for supporting flows has not been developed for NMFS BO (Jun 29) Action III The actual amount diverted is reduced because of supplies from the Los Vaqueros project. The existing and future Los Vaqueros storage capacity is 16 TAF. Associated water rights for Delta excess flows are included. 12 Under Existing Conditions it is assumed that SWP Contractors demand for Table A allocations vary from 3. to 4.1 MAF/year. Under the Future No Action baseline, it is assumed that SWP Contractors can take delivery of all Table A allocations and Article 21 supplies. Article 56 provisions are assumed and allow for SWP Contractors to manage storage and delivery conditions such that full Table A allocations can be delivered. Article 21 deliveries are limited in wet years under the assumption that demand is decreased in these conditions. Article 21 deliveries for the NBA are dependent on excess A-6

35 Appendix A: CalSim II Assumptions conditions only, all other Article 21 deliveries also require that San Luis Reservoir be at capacity and that Banks PP and the California Aqueduct have available capacity to divert from the Delta for direct delivery. 13 Mokelumne River flows reflect EBMUD supplies associated with the Freeport Regional Water Project. 14 The CCWD Alternate Intake Project, an intake at Victoria Canal, which operates as an alternate Delta diversion for Los Vaqueros Reservoir. 15 D-1644 and the Lower Yuba River Accord are assumed to be implemented for Existing and Future No Action baselines. The Yuba River is not dynamically modeled in CALSIM II. Yuba River hydrology and availability of water acquisitions under the Lower Yuba River Accord are based on modeling performed and provided by the Lower Yuba River Accord EIS/EIR study team. 16 Sacramento Area Water Forum Lower American River Flow Management Standard is not included in the CACMP. Reclamation has agreed in principle to the Flow Management Standard, but flow specifications are not yet available for modeling purposes. 17 It is assumed that either VAMP, a functional equivalent, or D-1641 requirements would be in place in Footnote removed. 19 In cooperation with Reclamation, National Marine Fisheries Service, Fish and Wildlife Service, and Ca Department of Fish and Game, the Ca Department of Water Resources has developed assumptions for implementation of the FWS BO (Dec 15 th 28) and NMFS BO (June 4 th 29) in CALSIM II. 2 Current ACOE permit for Banks PP allows for an average diversion rate of 6,68 cfs in all months. Diversion rate can increase up to 1/3 of the rate of San Joaquin River flow at Vernalis during Dec 15th Mar 15th up to a maximum diversion of 8,5 cfs, if Vernalis flow exceeds 1, cfs. 21 Acquisitions of Component 1 water under the Lower Yuba River Accord, and use of 5 cfs dedicated capacity at Banks PP during Jul Sep, are assumed to be used to reduce as much of the impact of the Apr-May Delta export actions on SWP contractors as possible. 22 Delta actions, under USFWS discretionary use of CVPIA 346(b)(2) allocations, are no longer dynamically operated and accounted for in the CALSIM II model. The Combined Old and Middle River Flow and Delta Export restrictions under the FWS BO (Dec 15 th 28) and the NMFS BO (June 4 th 29) severely limit any discretion that would have been otherwise assumed in selecting Delta actions under the CVPIA 346(b)(2) accounting criteria. Therefore, it is anticipated that CVPIA 346(b)(2) account availability for upstream river flows below Whiskeytown, Keswick and Nimbus Dams would be very limited. It appears the integration of BO RPA actions will likely exceed the 346(b)(2) allocation in all water year types. For these baseline simulations, upstream flows on the Clear Creek and Sacramento River are pre-determined based on CVPIA 346(b)(2) based operations from the Aug 28 BA Study 7. and Study 8. for Existing and Future No Action baselines respectively. The procedures for dynamic operation and accounting of CVPIA 346(b)(2) are not included in the CALSIM II model. 23 Only acquisitions of Lower Yuba River Accord Component 1 water are included. Key: Ag = agricultural ACOE = Army Corps of Engineers BO = Biological Opinion BDCP = Bay-Delta Conservation Plan CALFED = CALFED Bay-Delta Plan CCWD = Contra Costa Water District cfs = cubic feet per second CVP = Central Valley Project CVPIA = Central Valley Project Improvement Act DFG = California Department of Fish and Game DMC = Delta-Mendota canal DWR = California Department of Water Resources D-xxxx = Water Right Decision EBMUD = East Bay Municipal Utility District EIS = Environmental Impact Statement FC&WSD = Flood Control and Water Service District FERC = Federal Energy Regulatory Commission FRSA = Feather River Service Area FRWP = Freeport Regional Water Project FWS = Fish and Wildlife Service KCWA = Kern County Water Agency LYRA = Lower Yuba River Accord MAF/yr = million acre-feet per year M&I = municipal and industrial MWD = Metropolitan Water District NMFS = National Marine Fisheries Service NPS = National Park Service PCWA = Placer County Water Agency PP = Pumping Plant Reclamation = United States Department of the Interior, Bureau of Reclamation ROD = Record of Decision SBA = South Bay Aqueduct SEWD = Stockton East Water District A-7