Sustainable Management Related to Basin Storage
SECTION 10.
SUSTAINABLE MANAGEMENT
RELATED TO BASIN STORAGE The total volume of groundwater storage in the OCWD Basin is estimated to be 66 million acre- feet (OCWD, 2007). The total potential storage volume in the Santa Ana Canyon Management Area is estimated to be 43,500 acre-feet, as described in Section 3.2.3.
10.1 DEFINITION OF SIGNIFICANT AND UNREASONABLE REDUCTION IN STORAGE
As with groundwater levels, no long-term reduction in groundwater storage is foreseen in the Santa Ana Canyon Management Area; however, if that were to occur, a decline in groundwater storage could reach a significant and unreasonable level if one more of the following occurred due to a reduction in storage: 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.
10.2 DETERMINATION OF MINIMUM THRESHOLDS
It is not possible to determine a minimum threshold at this time since no undesirable effects due to a change in groundwater storage levels have occurred in the past and are not foreseen in the future . Nevertheless, OCWD’s monitoring program continuously tracks water levels, which is a proxy for groundwater storage, and groundwater quality in the Management Area. If water levels showed 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
10-1
Appendix F - 267
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