By implementing sustainable water strategies decades ago, including the use of recycled water for irrigation purposes and an aggressive groundwater replenishment program, the Coachella Valley Water District in Southern California has been able to carefully marshal its most valuable resource: The vast aquifer that lies beneath the valley floor.

The need for sustainable water-supply practices is amplified in the arid valley, which stretches from roughly Palm Springs south to the Salton Sea, because it receives an average of only about 3 inches of rainfall per year. As such, almost all of its drinking water comes from the Coachella Valley aquifer, which holds an estimated 39 million acre-feet of water.

To sustain the aquifer, the utility operates a groundwater replenishment program that effectively relies on two annual allocations of imported water from the Colorado River and the State Water Project. The latter distributes water from snowpack melt in northern California to 29 different customers, including the CVWD, says Carrie Oliphant, the utility’s director of engineering.

(Technically, because there’s no physical connection between the southernmost SWP facilities and the Coachella Valley and it would be astronomically expensive to build one, the CVWD forged a water exchange agreement with an agency called the Metropolitan Water District of Southern California. The utility trades water it receives from the SWP for an equal amount of Colorado River water from the MWD.)

The utility also reduces dependence on groundwater by recycling nearly 5.5 billion gallons of wastewater annually for irrigation use, using a high-level treatment process at two of its five wastewater treatment plants.

“For decades, we’ve undertaken a very conscious planning effort to ensure we have enough water for the future, knowing we live in this very dry desert climate,” Oliphant says. “Back when the CVWD was formed in 1918, the leaders of this organization had a lot of foresight to secure surface water supplies, knowing it would be something we’d need as the valley became more urbanized.

“For example, as an ever-growing population produced more and more wastewater, it just made sense to recycle it and use it as another source for irrigating golf courses,” Oliphant continues. “For us, necessity was the mother of invention.”

For its efforts, the district in 2022 was one of only four water utilities nationwide to win a Sustainability Water Utility Management Award from the Association of Metropolitan Water Agencies. The group advocates for water systems on federal policy issues and fosters programs for sustainable, innovative utility management.

Reducing groundwater use

The groundwater replenishment program dates back to the 1920s, when the utility built replenishment facilities designed to capture natural water runoff from the surrounding mountains and reduce groundwater pumping for agricultural use, Oliphant explains.

The utility now operates four replenishment facilities, which essentially are large ponds where water is delivered via open channels and pipelines. Water in the ponds naturally percolates through the sandy native soil and refills the aquifer.

Colorado River water, which is used for agricultural purposes, golf course irrigation and groundwater replenishment, is transported to the valley via the 123.5-mile-long Coachella Canal, completed in 1948.

In 2022, the CVWD received 339,000 acre-feet of water from the Colorado River and another  6,918 acre-feet of water from the SWP for replenishment and irrigation purposes. (The utility is supposed to receive 138,350 acre-feet of water annually from the SWP, but the amount varies according to state water conditions, which are affected by droughts.) And on average, another 52,000 acre-feet of natural runoff from mountain streams also trickles into the aquifer.

Since 1973, the utility has supplied 4.56 million acre-feet of imported water for replenishment efforts, according to utility statistics. To put that in perspective, about 3 million acre-feet of water is sufficient to satisfy the annual water needs of 6 million families of four, the district says.

And the replenishment program is working; according to a 2020 report from the United States Geological Survey, the aquifer level has increased.

“Thanks to our conservation efforts and our recycled-water programs, we’re no longer in an overdraft situation,” Oliphant notes.

Recycled water is key

The utility’s recycled-water program started in 1968 in an effort to decrease the use of groundwater for irrigation. Currently the district produces 5.47 billion gallons of recycled water via high-level treatment processes at two of the utility’s five wastewater treatment plants.

“The wastewater gets treated to a tertiary level,” Oliphant notes. “One of our larger wastewater treatment plants that serves a majority of the valley started recycling water in 1987 and another plant started producing recycled water in 1997.” (Another plant that recycled water was decommissioned in 2017.)

The recycled water is distributed to customers via 31 miles of pipelines.

Another 260,000 acre-feet of supplemental water for irrigation comes from the utility’s allocation of Colorado River water, delivered directly to farmers and golf courses by the Coachella Canal and 485 miles of pipelines.

Furthermore, about two dozen customers — mostly golf courses and homeowner’s associations — use a nonpotable blend of recycled water and Colorado River water for irrigation during summer, when demand outstrips the supply of recycled water, Oliphant says.

Golf courses also helped reduce demand for irrigation water by removing 165,420 acres of turf from 2015 through 2018. That saves more than 956 acre-feet of water annually, utility figures show.

Moreover, slightly more than half of the area’s 105 golf courses use a nonpotable water source for irrigation.

Conservation is critical

Aggressive and effective water conservation efforts also have reduced the region’s reliance on groundwater. Since July 2020, the CVWD has invested more than $19.5 million to fund rebate and incentive programs that encourage residents to swap out old, water-guzzling toilets for low-volume units; remove grass lawns from their yards; and install smart controllers and leak-detection monitors for irrigation systems.

The programs are making an impact. From 2013 to 2022, customers reduced water consumption by 13% — a decrease of more than 4.8 billion gallons of water. And since 2009, customers have converted more than 23.5 million square feet of grass into desert-friendly landscaping, spurred by turf-conversion incentive programs that have saved another 29,195 acre-feet of water since 2009, according to district figures.

Additionally, more than 13,000 customers have received rebates for outdoor conservation programs since 2006. That’s important because nearly 70% of the water used by residents goes toward outdoor use, Oliphant says.

“These residential conservation programs are a high priority because over-watering outdoors is one of the most common causes of water waste in the Coachella Valley. The more we can make conservation a way of life in the valley, the more everyone benefits for years to come.”

The utility also has taken other steps to conserve water. For example, it minimizes water loss by using pipes to deliver Colorado River water for irrigation and by metering all properties served. This results in only a 5% system loss, low compared to industry standards, utility officials say.

The CVWD also lined a 49-mile stretch of the Coachella Canal, which prevents 132,000 acre-feet of water annually from seeping into the ground, according to utility figures.

A rich legacy

The CVWD was established back in 1918. Their goal: Protect local water resources from outside interests and bring imported water to the area for agricultural irrigation and, later on, for groundwater replenishment. That led to building the Coachella Canal and securing Colorado River water rights.

Since then, the utility has evolved into a sophisticated, multipronged organization that supplies potable water, replenishes the aquifer, provides regional stormwater protection, operates sewer systems, practices water conservation and produces recycled water, Oliphant notes.

Yet despite all these efforts, programs and achievements, utility officials must remain alert to water issues, even though recent record snowfalls and rainfall have eased drought concerns.

“This year the snowpack was good and we received a lot of rain,” Oliphant says. “But the fact remains that we’re still reliant on imported water and there’s always the possibility that drought conditions will impact that. “It’s one of the major challenges we face.

“But our future water supply is in good shape, thanks to our long-term water management program — replenishing the Coachella Valley aquifer with imported water, reducing customer water use through conservation programs and increasing the supply and use of recycled water,” she continues.

“Nonetheless, we have to remain vigilant and keep looking for innovative ways to reduce water use and maintain the existing infrastructure to ensure water for future generations.”