A new article by the U.S. Geological Survey (USGS) calls efforts to mitigate land subsidence in the Coachella Valley “an emerging success story,” a finding that is echoed by analysis completed by local water agencies.
The USGS article, published in the Proceedings of the International Association of Hydrological Studies, notes Coachella Valley Water District (CVWD) has been concerned about land subsidence due to groundwater use since the mid-1990s. The USGS found that 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. The improvement includes some of the historically most overdrafted areas in the southern 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; uplift was observed in some areas.
According to the article, “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.”
These findings are also evident in an annual analysis of groundwater levels that shows significant increases over the past 10 years throughout most of the Coachella Valley.
The two annual reports for the 2018-19 water year, one on the Indio Subbasin and the other on the Mission Creek Subbasin, which make up most of the valley’s aquifers, were submitted before the State’s April 1 deadline.
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 resulted in the positive trends observed in groundwater storage in both 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, and the unincorporated communities of Thousand Palms, Thermal, Bermuda Dunes, Oasis, and Mecca.
The Indio Subbasin report shows that over the past ten years there were significant increases in groundwater levels in most of the subbasin in the range of 7-40 feet. These gains highlight the progress towards long-term sustainable management of the subbasin.
The Mission Creek Subbasin is located under Desert Hot Springs and the unincorporated area of Indio Hills.
This subbasin also shows that over the past 10 years the average groundwater level change increased more than 13 feet. Groundwater storage in the subbasin shows positive trends since 2005 helping to maintain sustainable groundwater levels.
There were localized portions of decreased water levels in the mid-valley area of the Indio Subbasin. This area is now benefiting from CVWD’s Palm Desert Groundwater Replenishment Facility.
CVWD is also continuing efforts to connect more golf courses to nonpotable water such as recycled or Colorado River water instead of groundwater.
The Annual Reports were submitted to the California Department of Water Resources to comply with the reporting requirements of the Sustainable Groundwater Management Act. To read the full reports, visit cvwd.org/sgma.
2018-2019 Indio Subbasin Alternative Annual Report
2018-2019 Mission Creek Subbasin Alternative Annual Report
The Coachella Valley Water District is a public agency governed by a five-member board of directors. The district provides domestic and irrigation water, agricultural drainage, wastewater treatment and reclamation services, regional storm water protection, groundwater management and water conservation. It serves approximately 108,000 residential and business customers across 1,000 square miles, located primarily in Riverside County, but also in portions of Imperial and San Diego counties.