Sustainable Management Related to Groundwater Levels
SECTION 9. SUSTAINABLE MANAGEMENT RELATED TO GROUNDWATER LEVELS
9.1 HISTORY
As shown on Figure 3-3, groundwater levels in the Santa Ana Canyon Management Area have been steady over the last 20 years. Given the large amount of surface inflow to the Santa Ana Canyon Management Area relative to the amount of groundwater production, groundwater levels are expected to remain steady in the future.
9.2 MONITORING OF GROUNDWATER LEVELS
OCWD monitors groundwater levels at multiple wells in the Santa Ana Canyon Management Area and will continue to do so in the future.
Within the last five years, several wells at the Green River Golf Course were added to the OCWD monitoring network and destroyed well SCE-YLCS was replaced in the network by well EMA-AH5.
9.3 DEFINITION OF SIGNIFICANT AND UNREASONABLE LOWERING OF GROUNDWATER LEVELS
No long-term reduction in groundwater levels is foreseen in the Santa Ana Canyon Management Area; however, if that were to occur, a decline in groundwater levels could reach a significant and unreasonable level if one more of the following occurred as a result of reduced groundwater levels: 1. Significant and unreasonable loss of riparian habitat along the Santa Ana River. 2. Significant and unreasonable loss of well production capacity. 3. Degradation of water quality that significantly impacts the beneficial uses of groundwater.
9.4 DETERMINATION OF MINIMUM THRESHOLDS
It is not possible to determine a minimum threshold at this time since no undesirable effects due to water levels have occurred in the past and are not foreseen. Nevertheless, OCWD’s monitoring program continuously tracks water levels and groundwater quality in the Management Area. If water levels started to show a consistent long-term decline, OCWD’s monitoring program would be expanded to examine potential impacts to riparian habitat, well yields, and groundwater quality. If impacts were observed, action would be taken, and minimum thresholds would be evaluated and established as appropriate.
BASIN 8-1 ALTERNATIVE 2022 UPDATE
9-1
Appendix F - 266
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