View File - Development Services - City of Oxnard

WATER RESOURCES TECHNICAL REPORTthose growers pumping groundwater (2,814 AFY). Based on the model simulations,water levels increased up to 2.5 feet in the UAS and up to 10 feet in the LAS. These smallincreases will incrementally help to further minimize the already low potential thatexists for coastal landward flow in the UAS and incrementally decrease the severeoverdraft conditions and water quality degradation that exist in the LAS of the southernOxnard Plain and Pleasant Valley areas.• Scenario 1c will result in an additional moderate to large rise in groundwater elevationsat the Phase 1 pilot injection well in the LAS as a result of injecting 534 AFY of recycledwater at this location. Based on the model simulations, water levels increased up to25 feet in the LAS at the injection well and up to 5 feet in the UAS across the southernOxnard Plain and Pleasant Valley areas with this additional measure. These additionalincreases in water levels will begin to significantly help decrease the severe overdraftconditions and water quality degradation that exist in the LAS of the southern OxnardPlain.7.1.2 Groundwater Recovery for Potable UseAs noted above, the quantities of water recharged and recovered are relatively low forPhase 1 compared to Phase 2. Recovery of these relatively lower quantities of water forpotable use in Phase 1 (either 2,814 AFY of in-lieu recharge, or 3,348 AFY of in-lieu rechargeplus direct injection) resulted in equally minor decreases in groundwater elevations, whichwere less than 10 feet in both the UAS and LAS across the northern Oxnard Plain andOxnard Forebay areas. In the UAS, these small decreases will not significantly affect thealready low potential for coastal landward flow, even during extended, drier climaticperiods. In the LAS, these small decreases may incrementally increase the moderatepotential for landward flow that appears to exist from the modeling data, particularlyduring drier years and in the fall when water levels are seasonally low.Although groundwater level increases in the southern Oxnard Plain and Pleasant Valleyarea and decrease in the northern Oxnard Plain and Forebay area, the magnitude of thesechanges is minor compared to the historical and simulated future Base Case water levelfluctuations (Figure 6-16). As described in Section 2.0, short- and long-term climatic cycleswill play a major role in dictating the groundwater elevations across the Oxnard Plain andPleasant Valley areas; and the effects of those water level changes will be greater than thewater level changes from the Phase 1 scenarios of the GREAT Program.7.1.3 Reduction in OverdraftThe reduction in overdraft for each of the Phase 1 scenarios relative to the Base Case areas follows.W112003002SCO LW1458.DOC/ 033390002 96