Orestimba Creek Recharge and Recovery Expansion Project (Project)
Purpose and Need for the Proposed Action/Project Objectives
The State of California is currently experiencing unprecedented water management challenges due to severe drought in recent years. Both the State and Federal water projects are forecasting very low storage conditions in all major reservoirs. In addition, south of Delta Central Valley Project (CVP) contractors frequently experience reduced water supply allocations due to hydrologic conditions and/or regulatory requirements.
During dry periods, when surface water supplies are scarce, growers rely on groundwater or other sources of supply to meet their irrigation needs. Excessive groundwater pumping strains aquifers that are already in a state of overdraft, dropping the water level in some wells substantially and causing other wells to go dry. Additional constraints under California’s Sustainable Groundwater Management Act (SGMA) and the applicable Groundwater Sustainability Plan(s) (GSP) that apply to CCID and DPWD may limit the amount of groundwater pumping available, further reducing water supplies when they are most needed. As such, water purveyors, such as CCID and DPWD, need to find alternative sources of water to fulfill existing demands to stave off substantial impacts to crop production, the regional economy, loss of jobs, disadvantaged communities, etc. The purpose of the Proposed Action/Project is to provide a long-term solution to support regional agricultural operations by using excess storm and floodwaters with the objective to recharge groundwater supplies for future extraction with a 10% leave behind that would also help to prevent subsidence and reduce groundwater basin overdraft.
Under the Proposed Action/Project Reclamation would issue a land use authorization to CCID for the installation, operation, and maintenance of facilities on Reclamation land as described in more detail below. In addition, CCID and DPWD propose to construct various infrastructure and recharge ponds that would expand the previously constructed Pilot Project.
The Proposed Action/Project includes five main components: (1) Securing a temporary and permanent water rights from Orestimba Creek, (2) Constructing diversion facilities and pipelines between Orestimba Creek, the DMC, and the recharge ponds, (3) Constructing recharge ponds (4) Developing recovery wells and associated pipelines, and (5) Conducting geotechnical and soil investigations to help determine the final design and delineate aquatic resources. In addition to the main components, staging areas for loading, unloading, and temporary storage of equipment and materials would be delineated within the work area boundaries. Maintenance would be done semi-annually. Maintenance activities include the removal of sediment, vegetation, and other materials to improve percolation capacity.
Sources of Recharged Water
Central California Irrigation District.
CCID in conjunction with the other members of the Exchange Contractors, would generate up to 16,500 AFY for recharge when supplies are available. The 16,500 AFY is comprised of existing water rights and the potential Water Right being pursued as part of the Proposed Action/Project. Supplies would consist of a combination of water from various sources such as conserved water, storm water and flood flows from adjoining watersheds for placement in the recharge ponds. The conserved water would be generated pursuant to the “Water Transfer Program for the San Joaquin River Exchange Contractors, 2014 – 2038”, approved by Reclamation in a Record of Decision dated July 30, 2013. In addition, diversion of up to 35 cfs of Orestimba Creek storm flows is a potential source of water to be captured and delivered into the recharge ponds, as well as flood flows (through exchange via the DMC) from both the San Joaquin and Kings Rivers. The Proposed Action/Project is sized for recovery in two dry years and recharge in one wet year per 10 years. CCID may have 8 years of recharge to develop the account to draw from in the two dry years. However, the Project design is based on one wet year per 10 years to achieve storage sufficient for recovery in two dry years.
Del Puerto Water District.
The DPWD is under contract with Reclamation for its water supply, which is delivered from the DMC, a feature of the Central Valley Project (CVP). The contract provides for the delivery of up to 140,210 AFY. DPWD will develop and provide up to 16,500 AFY for recharge when supplies are available. The 16,500 AFY will be made available from its contract supplies and will be generated through DPWD’s use of various conservation and water resources projects to make the project water available in certain year types. These include DPWD’s water conservation program, DPWD’s program to generate water for its own use and for use by the local refuges through several existing contracts with Reclamation to develop CVPIA Level 2 (L2) supplies (GWD Exchange/Volta Wells Exchange and the North Valley Regional Recycled Water Program (NVRRWP)), as well as the use of non-CVP supplies developed under the terms and conditions of various Warren Act contracts. The DPWD also has several existing contracts with Reclamation which support the development of Incremental Level 4 (IL4) Central Valley Project Improvement Act (CVPIA) water supplies for Reclamation’s Refuge Water Supply Program in exchange for the delivery of CVPIA Level 2 (L2) supplies for DPWD’s use (NVRRWP/GWD Exchange/Volta Wells Exchange), as well as access to non-CVP supplies developed under the terms and conditions of various Warren Act contracts. These sources, as well as the use delivery of Section 215 water directly to the Proposed Action/Project when made available by Reclamation, would allow DPWD to generate up to 16,500 AFY of supply. Additionally, diversion of up to 35 cfs of Orestimba Creek storm flows is a potential source of water to be recharged in the Proposed Action/Project. It is assumed that there would be two dry years and one wet year per recharge and recovery cycle.