The U.S. Geological Survey (USGS) finds that three water projects are linked to markedly improved groundwater levels in the Coachella Valley in Southern California’s Riverside County.
A new article published by the USGS calls efforts by the Coachella Valley Water District (CVWD) to mitigate land subsidence and replenish groundwater supplies “an emerging success story.”
The Coachella Valley’s annual average of 3 inches of rain along with snowmelt from surrounding mountains is not nearly enough to naturally replenish what is pumped from the groundwater basin to meet local water demands. Consequently, the valley’s groundwater basin is in overdraft. In an ongoing effort to ensure that a reliable supply of groundwater will continue to be available across the entire valley, the CVWD has implemented several projects to address groundwater overdraft that fall under three categories – groundwater substitution, conservation, and managed aquifer-recharge.
“The implementation of three projects in particular — replacing groundwater extraction with surface water from the Colorado River and recycled water (Mid-Valley Pipeline project), reducing water usage by tiered-rate costs, and increasing groundwater recharge at the Thomas E. Levy Groundwater Replenishment Facility — are potentially linked to markedly improved groundwater levels and subsidence conditions, including in some of the historically most overdrafted areas in the southern Coachella Valley,” says the USGS report.
USGS notes that, “the water management strategies implemented by the CVWD can inform managers of other overdrafted and subsidence-prone basins as they seek solutions to reduce overdraft and subsidence.”
Annual analysis of groundwater levels by local water agencies shows significant increases over the past 10 years throughout most of the Coachella Valley. Prior to about 2010, water levels persistently declined, and some had reached historically low levels by 2010. Since about 2010, however, groundwater levels have stabilized or partially recovered, and subsidence has stopped or slowed substantially almost everywhere it previously had been observed.
Successful groundwater replenishment programs along with continued efforts to conserve, reduce water waste, and to connect customers to the nonpotable water system for irrigation purposes have resulted in the positive trends observed in groundwater storage in both the Indio & Mission Creek subbasins during the past 10 years.
- The Indio Subbasin is located under the cities of Palm Springs, Cathedral City, Rancho Mirage, Palm Desert, Indian Wells, La Quinta, Indio, and Coachella. Over the past ten years, there were significant increases in groundwater levels in the range of 7-40 feet.
- The Mission Creek Subbasin is located under Desert Hot Springs and Indio Hills. Over the past 10 years, the average groundwater level change increased more than 13 feet.
Source: CA Water News Daily