View File - Development Services - City of Oxnard

WATER RESOURCES TECHNICAL REPORT• Concentrate Collection System. A new concentrate 1 collection system would bedeveloped to serve the AWTF, the regional desalter, and various existing industrialbrine producers. The proposed concentrate collection system would collect the reverseosmosis (RO) concentrate produced by these facilities instead of allowing it to dischargeinto the existing City sewer system. This would make treatment of recycled waterproduced by the TTF and AWTF more efficient in meeting the reuse criteria foragricultural irrigation and direct aquifer injection.• Permeate Delivery System. A new permeate¹ distribution system would be developedto provide high quality water to industrial users. This would reduce the need to conductreverse osmosis (RO) treatment of City potable water, and also reduce discharges ofconcentrate to the current sanitary sewer system of the new concentrate collectionsystem.The GREAT Program, which would be implemented in two phases, is designed to provide areliable and affordable 2 source of high quality water. The objective of Phase 1 is to develop awater supply reliability and recycling program while maximizing use of current facilities tomeet current water supply deficits. Once Phase 1 is implemented and evaluated, theobjective of Phase 2 is to expand Phase 1 facilities and build new facilities to accommodatethe projected water supply needs that the City identifies in its 2020 general plan update.The ultimate size of the Phase 2 facilities is unknown, and will depend both on the level ofplanned growth as identified in the City’s general plan update, once completed, and on theresults of the Phase 1.1.2 Scope of WorkThe water resources technical study was conducted to assess the effects on groundwaterelevations from the (1) in-lieu groundwater recharge using recycled water for agriculturalirrigation, (2) direct injection groundwater recharge using recycled water, and(3) groundwater recovery for potable use. The technical study includes the followingmajor elements:• The environmental setting was established, including information on climate, surfacewater resources, and groundwater resources.• The existing supply and demand of potable water and water used for agriculturalirrigation was identified and reviewed.• The USGS numerical groundwater flow model of the Santa Clara-Calleguas Basin andthe UWCD update to that model were reviewed.1 In situations where brackish groundwater is treated with membrane filtration technology, two products are produced:“permeate” and “concentrate.” Permeate is produced through the removal of salts and is intended for consumption by varioususers. Concentrate is the portion that contains the concentrated salts and requires disposal. The terms “brine” and“concentrate” are used interchangeably for the purposes of discussion in this document.2 The GREAT Program would provide the City of Oxnard a more affordable source of high quality water in comparison to thecost of water (including penalties assessed) as a result of overpumping current City groundwater allocation or exceeding theCity’s allocation of water from the State Water Project.W112003002SCO LW1458.DOC/ 033390002 3