Integrated Water Resources Planning
Zone 7 Water Agency/Alameda County, California

West Yost prepared an Integrated Water Resources Plan (IWRP) that linked water supply needs to an integrated evaluation of all aspects of available water resources and conveyance/transmission and treatment facilities, to create a single flexible plan which could be adopted by the Board and implemented by staff.

Zone 7’s long-range water demand projections indicated the need for an additional 38,000 acre-feet of water supply. Reclaimed water and conservation, imported water, and an increased use of groundwater will supplement the water supply demand. West Yost assisted the agency in evaluating and prioritizing water supply opportunities and analyzing conveyance facilities into and throughout the valley. The feasibility of potential water supply sources was analyzed based on economics, costs, institutional arrangements, operational flexibility, average annual and firm yield, water quality and reliability, and potential environmental impacts. The work product was a proposed strategy and implementation/action plan identifying which supply options to pursue, and a defined time schedule.

West Yost’s IWRP work included projection of existing supply quantities and reliability under all hydrologic conditions; projection of potable and non-potable demands; evaluations and recommendations for supplemental supply acquisition; development of an aggressive conjunctive use program; and analysis and development of a phased Water Conveyance Master Plan to ensure that facilities would be completed on time to deliver the required water when needed. This IWRP integrated a program to use locally available Title 22 recycled water to offset non-potable water demands and preserve available supplies for the “highest and best use.”

For Zone 7 Water Agency, West Yost was responsible for analyzing the impacts of conveyance, treatment, storage, and transmission on Zone 7 facilities of the proposed Berrenda Mesa water entitlement transfer for use in Dougherty Valley. Analysis included demand calculations, review of the capacity of the future contractor’s share of the South Bay Aqueduct with the California Department of Water Resources, the yield of Del Valle Reservoir, and needed transmission facilities.