DWR Recommended Action 2 . Staff recommend a basin-wide water budget utilizing inflow and outflow information from each management area or a water budget for each management area be provided in accordance with the GSP regulations (CCR 23 Section 354.18).
OWWD Response:
Over the years, OCWD has developed a comprehensive data collection system to characterize basin inflows and outflows. In an average year, approximately 80 percent of the inflow to the basin is measured and all of the groundwater production is measured and accounted for. In addition, every year, the change in groundwater storage is estimated based on water level changes in the three basin aquifers. This process defines the current storage condition in the basin and refines the net incidental (unmeasured) recharge portion of the water budget. Section 4 of the OCWD Management Area section of the Alternative describes the various elements of the water budget. The five-year water budget presented in the OCWD Management Area of the report is reproduced below.
Table 4-1: Water Budget, WY2016-17 to 2020-21 (OCWD Management Area)
FLOW COMPONENT
2016-17
2017-18
2018-19
2019-20
2020-21
INFLOW
Santa Ana River baseflow
70,000
65,400
98,000
74,500
76,400
Santa Ana River stormflow
65,400
24,100
63,700
79,500
36,600
Recycled Water (GWRS/Alamitos Barrier)
98,000
106,400
97,200
99,700
101,700
Imported Water
50,400
66,100
40,300
18,100
0
Net Estimated Unmeasured or Incidental Recharge*
67,900
26,200
45,600
41,400
19,100
TOTAL INFLOW:
351,700
288,200
344,800
313,200
233,800
OUTFLOW
Groundwater Production
300,700
237,200
303,800
277,200
281,800
TOTAL OUTFLOW:
300,700
237,200
303,800
277,200
281,800
CHANGE IN STORAGE:
51,000
51,000
41,000
36,000
(48,000)
The water budget presented in Table 4-1 is essentially the water budget for Basin 8-1, except for the La Habra Management Area. The water budget for the Santa Ana Canyon Management Area shows that this area provides a net source of water to the OCWD Management area that is captured in the surface
Appendix F - 283
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