Draft 2025 Urban Water Management Plan

Executive Summary

four percent of the total available water supply (see 2017 Alternative, Santa Ana Canyon Management Area).

Table 1-1: Agencies in Santa Ana Canyon Management Area

Agency

City of Anaheim City of Chino Hills City of Yorba Linda City of Corona Orange County Water District County of Orange Riverside County Yorba Linda Water District

Table 1-2: Water Budget, 5-Year Average (2016-21)

Flow Component

5-Yr Avg: 2016-21 (afy)

INFLOW Santa Ana River Base Flow Santa Ana River Storm Flow

76,860 78,750

Subsurface Inflow

6,000

TOTAL INFLOW

161,610

OUTFLOW Santa Ana River Base Flow Santa Ana River Storm Flow

76,120 78,750

Evapotranspiration

740

Groundwater Production

1,000 5,000

Subsurface Outflow

TOTAL OUTFLOW

161,610

Per the monitoring discussed in Section 5, groundwater levels in the Santa Ana Canyon Management Area are relatively stable, having been consistently 20 to 30 feet below ground surface since 1991, indicating that the supply of subsurface inflow and surface water from the Santa Ana River is more than sufficient to sustain local groundwater production. Groundwater quality is suitable for irrigation and potable uses. Native groundwater from the surrounding foothills tends to have naturally elevated total dissolved solids (TDS) and manganese concentrations. Most wells in the canyon appear to produce a blend of infiltrated Santa Ana River water and native groundwater, with some wells producing more infiltrated Santa Ana River water than others.

BASIN 8-1 ALTERNATIVE 2022 UPDATE

1-3

Appendix F - 245

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