View File - Development Services - City of Oxnard

WATER RESOURCES TECHNICAL REPORTPumpage on the Oxnard Plain and Pleasant Valley over the 1984-1993 period determinedfor the USGS model was 91,400 and 22,200 AFY, respectively, for a total of 113,600 AFY. TheCity of Oxnard baseline FCGMA groundwater is 6,814, which was determined by the actualextractions of the City during the 5-year base period from 1985 to 1989. Combined with theCity UWCD suballocation of 6,238 AFY, this total of 13,052 AFY represents approximately11 percent of the average 91,400 AFY of groundwater pumpage during the 1984-1993time frame.2.6.3 Groundwater QualityThe overall groundwater quality across the Forebay, Oxnard Plain, and Pleasant Valley isgood as indicated by total dissolved solids (TDS) concentrations, which are shown inFigure 2-21 for the UAS and LAS for spring and fall 2002 conditions. In general, TDSconcentrations are within the range of approximately 500 to 1,500 milligrams per liter(mg/L) in areas that do not have degraded water quality and not including the Semi-Perched Aquifer. The water quality in the Semi-Perched Aquifer can vary widely with timeand location, ranging from fresh to brackish. Currently, there is limited usage of water fromthis zone for supply purposes.With the exception of the Semi-Perched Aquifer, this overall good quality of groundwater isreflected in the beneficial use designations and water quality objectives from the WaterQuality Control Plan for the Los Angeles Region (Basin Plan) as set by the RWQCB. Thebeneficial uses of groundwater, as indicated in the Basin Plan, are as follows:RWQCB Basin Plan Beneficial Uses of GroundwaterBeneficial UsesOxnard PlainGroundwater Basin MUN IND PROC AGR• Oxnard Forebay E E E E• Confined aquifers E E E E• Unconfined perched aquifers E P -- EPleasant Valley• Confined Aquifers E E E E• Unconfined Perched Aquifers P E E EMUN = Municipal and Domestic SupplyIND = Industrial Service SupplyPROC = Industrial Process SupplyAGR = Agricultural SupplyE = Existing beneficial useP = Potential beneficial useW112003002SCO LW1458.DOC/ 033390002 23