Appendix 6 Surface Water Resources Line items and numbers identified or noted as “No Action Alternative” represent the “Existing Conditions/No Project/No Action Condition” (described in Chapter 2 Alternatives Analysis). Table numbering may not be consecutive for all appendixes. This page intentionally left blank. Contents Appendix 6: Surface Water Resources 6A Modeling of Alternatives 6B Water Resources System Modeling 6B1 Project Operations 6B2 River Operations 6B3 Delta Operations 6B4 Regional Deliveries 6C Upper Sacramento River Daily River Flow and Operations Modeling 6D Sensitivity Analysis Using the Latest CALSIM II Model This page intentionally left blank. Appendix 6A Modeling of Alternatives Line items and numbers identified or noted as “No Action Alternative” represent the “Existing Conditions/No Project/No Action Condition” (described in Chapter 2 Alternatives Analysis). Table numbering may not be consecutive for all appendixes. This page intentionally left blank. Appendix 6A Modeling of Alternatives CALSIM II and DSM2 Modeling Assumptions for Sites Reservoir Alternatives 6A.1 Introduction This appendix describes the assumptions for the CALSIM II and DSM2 modeling of the Existing Conditions, No Action Alternative, and Sites Reservoir Project (Project) alternatives included in the Sites Reservoir Project Draft Environmental Impact Report/Environmental Impact Statement (EIR/EIS). The following model simulation was prepared as the basis of evaluating the impacts of the Project alternatives: 1. Existing Conditions/No Project/No Action Condition The following model simulations of alternatives were prepared: 1. Alternative A – includes a 1.3-million-acre-foot (MAF) Sites Reservoir with conveyance to and from the reservoir provided by the existing Tehama-Colusa and Glenn-Colusa Irrigation District (GCID) Main canals and a new Delevan Pipeline (2,000-cubic-foot-per-second [cfs] diversion/1,500-cfs release) 2. Alternative B – includes a 1.8-MAF Sites Reservoir with conveyance to and from the reservoir provided by the existing Tehama-Colusa and GCID Main canals, and a new release–only Delevan Pipeline (1,500-cfs release) 3. Alternative C – includes a 1.8-MAF Sites Reservoir with conveyance to and from the reservoir provided by the existing Tehama-Colusa and GCID Main canals and a new Delevan Pipeline (2,000- cfs diversion/1,500-cfs release) 4. Alternative D – includes a 1.8-MAF Sites Reservoir with conveyance to and from the reservoir provided by the existing Tehama-Colusa and GCID Main canals and a new Delevan Pipeline (2,000- cfs diversion/1,500-cfs release); 480 thousand acre-feet (TAF) of Sites storage is reserved for local project participants in the Colusa Basin Existing Conditions/No Project/No Action Condition modeling assumptions were developed through a coordinated process with the Federal and State Lead Agencies to reflect the best CALSIM II and DSM2 model representation of the Reasonable and Prudent Actions (RPAs) in the 2008 Fish and Wildlife Service (USFWS) and 2009 National Marine Fisheries Service (NMFS) Biological Opinions (BOs). Alternatives A, B, and C modeling assumptions were developed by the North-of-Delta Offstream Storage (NODOS) EIR/EIS Lead Agencies, Alternative D modeling assumptions were developed by the Sites Project Authority (Authority). SITES RESERVOIR PROJECT DRAFT EIR/EIS 6A-1 Appendix 6A Modeling of Alternatives 6A.2 Assumptions for Existing Conditions/No Project/ No Action Condition Model Simulations As described in Chapter 2 Alternatives Analysis, because facilities, regulatory regime, and water demands would be similar under the Existing Conditions and the No Project/No Action Alternative under year 2017 conditions, the analysis in this EIR/EIS assumes that the Existing Conditions baseline and No Project/No Action Alternative are similar and substantially the same baseline condition. Therefore, the identification of impacts for this Draft EIR/EIS is based on the evaluation of the action alternatives compared to what is termed the “Existing Conditions/ No Project/No Action Condition.” This section presents the assumptions used in developing the CALSIM II and DSM2 model simulations for the Existing Conditions/No Project/No Action Condition used in the Sites Reservoir Draft EIR/EIS evaluation. The No Action Alternative CALSIM II and DSM2 models developed for the NODOS Feasibility Study and EIR/EIS were used for the Sites Reservoir Draft EIR/EIS Existing Conditions/No Project/No Action Condition. The modeling assumptions were selected by the California Department of Water Resources (DWR) and Bureau of Reclamation (Reclamation) management team for the NODOS Feasibility Study and EIR/EIS. The assumptions were selected to satisfy California Environmental Quality Act (CEQA) and National Environmental Policy Act (NEPA) requirements. The basis for these assumptions is described in the Chapter 2 Alternative Analysis. Assumptions that are applicable to the CALSIM II and DSM2 modeling are included in the following section. The Existing Conditions/No Project/No Action Condition assumptions include implementation of water operations components of the RPAs specified in the 2008 USFWS and 2009 NMFS BOs. The specific assumptions and implementation in the CALSIM II and DSM2 models were developed by a multiagency team comprised of fisheries and modeling experts from the DWR, California Department of Fish and Game (CDFG, now known as California Department of Fish and Wildlife [CDFW]), Reclamation, USFWS, and NMFS. In Section 6A.2.1 Existing Conditions/No Project/No Action Condition, the description of CALSIM II and DSM2 assumptions refer to the No Action Alternative. However, these assumptions are applicable to the Existing Conditions/No Project/No Action Condition in the Sites Reservoir Draft EIR/EIS. The detailed assumptions used in developing CALSIM II and DSM2 simulations for the Existing Conditions/No Project/No Action Condition are included in Section 6A.4 Existing Conditions/No Project/No Action Condition Modeling Assumptions Callout Tables, in Tables 6A-5 and 6A-6. Additional information is provided in the footnotes of each table. Table entries and footnotes refer to supporting appendix sections and other documents. Even though these tables show different assumptions for the Existing Conditions and the No Action Alternative, as previously noted, the No Action Alternative was used to represent the Existing Conditions/No Project/No Action Condition in the Draft EIR/EIS. The Existing Conditions/No Project/No Action Condition simulation was developed assuming Year 2030 level of development and regulatory conditions. The Existing Conditions/No Project/No Action Condition assumptions include existing facilities and ongoing programs that existed as of March 2017 (publication of the Notice of Preparation) that could affect or could be affected by implementation of the alternatives. The Existing Conditions/No Project/No Action Condition assumptions and the models do not include any restoration actions or additional conveyance over the current conditions. SITES RESERVOIR PROJECT DRAFT EIR/EIS 6A-2 Appendix 6A Modeling of Alternatives 6A.2.1 CALSIM II Assumptions for Existing Conditions/No Project/No Action Condition 6A.2.1.1 Hydrology Inflows/Supplies CALSIM II model includes the historical hydrology with projected 2030 modifications for the operations upstream of the rim reservoirs. Reservoir inflows, stream gains, diversion requirements, irrigation efficiencies, return flows and groundwater operation are all components of the hydrology for CALSIM II. Level of Development CALSIM II input hydrology is based on an analysis of agricultural and urban land use and population estimates. The assumptions used for Sacramento Valley land use result from aggregation of historical survey and projected data developed for the California Water Plan Update (Bulletin 160-98). Generally, land use projections are based on Year 2020 estimates (hydrology serial number 2020D09E). However, the San Joaquin Valley hydrology reflects draft 2030 land use assumptions developed by Reclamation. Where appropriate Year 2030 projections of demands associated with water rights and State Water Project (SWP) and Central Valley Project (CVP) water service contracts have been included. Specifically, projections of full build out are used to describe the American River region demands for water rights and CVP contract supplies and California Aqueduct and the Delta Mendota Canal SWP/CVP contractor demands are set to full contract amounts. Demands, Water Rights, CVP/SWP Contracts CALSIM II demand inputs are preprocessed monthly time series for a specified level of development (e.g. 2020) and per hydrologic conditions. Demands are classified as CVP project, SWP project, local project or non-project (e.g. pre-1914 water rights, in-Delta consumptive use etc.). CVP and SWP demands are separated into different classes based on the contract type. A description of various demands and classifications included in CALSIM II is provided in the 2008 Operations Criteria and Plan (OCAP) Biological Assessment Appendix D (Reclamation, 2008a). Non-project demands within each Depletion Study Area are based on the proportion of the acreage served by the projects versus the total acreage, for each land-use type. Non-project demands are satisfied from sources other than project storage and project conveyance facilities and are reduced as a function of water availability in the absence of project operations. Table 6A-1 includes the summary of the CVP and SWP project