La Habra-Brea Management Area
with water purchased from the California Domestic Water Company in a 250,000-gallon forebay to reduce the concentration of minerals prior to entering the City of La Habra’s distribution system (La Habra, 2014). Groundwater production wells in Brea are strictly used for irrigation purposes as the groundwater beneath the city has poor water quality and would require extensive treatment and blending with higher quality water to meet public health standards (Malcolm Pirnie, 2011). Table 3-3 below shows historical water quality for select constituents. Recent State database water quality results indicate reported exceedances in raw groundwater for nitrate, perchlorate, volatile organic compounds (VOCs), and radioactivity, with the most recent violation occurring in 2014 (Safe Drinking Water Information System).
Table 3-3: Historical Constituent Concentrations (1927-1977)
Constituent
Minimum
Maximum
Average
Specific Conductance
255
2,235
1,324
Total Dissolved Solids
269
1,696
943
Sulfate
0
672
174
Chloride
18
460
161
Nitrate
0
185
44
Fluoride
0
1.6
0.44
Total Hardness
75
931
489
Source: Montgomery, 1977.
3.2.6 Land Subsidence
Based on Orange County Water District’s 2015 Update to its Groundwater Management Plan, there is no evidence that the observed minimal land surface changes in portions of Orange County has caused, or are likely to cause, any structural damage within the area (OCWD, 2015). As long as groundwater elevations and storage within the basin are maintained within their historical operating ranges, the potential for problematic land subsidence is reduced. Additionally, the United States Geological Survey (USGS) does not show the La Habra Groundwater Basin as an area where there have been historical or current subsidence recorded due to either groundwater pumping, loss of peat, or oil extraction (USGS, 2021). There is also no evidence of land subsidence within the La Habra Groundwater Basin according to the Department of Water Resources’ SGMA Data Viewer. Vertical displacement estimates are
2017 BASIN 8-1 ALTERNATIVE
3-11
Appendix F - 28
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