Orange County Basin - Metropolitan Water District of Southern ...
Orange County Basin - Metropolitan Water District of Southern ...
Orange County Basin - Metropolitan Water District of Southern ...
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Chapter IV – Groundwater <strong>Basin</strong> Reports<br />
<strong>Orange</strong> <strong>County</strong> <strong>Basin</strong>s<br />
in the Huntington Beach area, likely due to oil withdrawal (OCWD, 2004). In the period<br />
between 1993 and 1999, land surface elevations declined about 0.5 inches per year in Santa Ana<br />
(OCWD, 2004). Despite the indications <strong>of</strong> land subsidence in the <strong>Orange</strong> <strong>County</strong> <strong>Basin</strong>, there<br />
has been no indication that these decreases have resulted in damage. By managing groundwater<br />
levels and storage, the potential for land subsidence can be reduced (OCWD, 2004).<br />
Source: Herndon, 2006<br />
GROUNDWATER QUALITY<br />
Figure 10-8<br />
Groundwater Elevation Contours – November 2005<br />
In general, groundwater in the main producing aquifers <strong>of</strong> the basins is <strong>of</strong> good quality with an<br />
average concentration <strong>of</strong> total dissolved solids (TDS) in the basin <strong>of</strong> 441 mg/L (OCWD, 2006).<br />
Ninety to 95 percent <strong>of</strong> basin pumping is from the main aquifers. A few localized areas <strong>of</strong><br />
shallow contamination exist in the basin, however, very little water is pumped from the shallow<br />
aquifers. Additionally, OCWD has implemented active projects and programs to remove<br />
contaminants from the shallow aquifers before they can migrate into the main producing<br />
aquifers.<br />
FINAL IV-10-16 September 2007
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