La Habra-Brea Management Area
In 1977, Montgomery Engineers completed a groundwater study for the City of La Habra and estimated the “probable long -term groundwater bas in yield” of the La Habra Groundwater Basin based on the natural recharge and natural discharge methods. Stetson conducted a re- evaluation of Montgomery’s 1977 safe yield analysis in 2013 to re-determine the estimated safe yield based on the natural recharge method. The average of these two methods (natural discharge and natural recharge) results in an approximate safe yield of 4,500 AFY. The City of La Habra has been producing groundwater since the late 1990s and monitoring static and pumping groundwater elevations since 2008. Previous investigations into groundwater levels and the safe yield have been used to manage the La Habra Groundwater Basin for over 10 years.
4.5 ESTIMATED WATER BUDGET
The estimated water budget is shown in Table 4-1 below. There is currently insufficient data to determine precise estimates of the water budget components; accordingly, the water budget is presented as ranges.
Table 4-1: Estimated Water Budget
Estimated Range 1
Budget Component
Inflows
Precipitation
1,600 - 1,800
Mountain Front Recharge
1,700 - 2,100
Incidental/Other Recharge
Unknown
Outflows
Subsurface Outflow
2,200 – 5,500
Groundwater Extraction
2,000 – 4,000
BALANCE 1
0
1 This water budget is based on previous historically estimated inflows and outflows in the La Habra Groundwater Basin. Available water level data show rising or stable groundwater levels indicating the Basin is in balance. Therefore, the historical estimates may not account for all of the recharge occurring in the Basin.
Sources: Montgomery, 1977. OCWD, 2015. Stetson, 2013.
2017 BASIN 8-1 ALTERNATIVE
4-2
Appendix F - 33
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