For the last two years, California’s Agua Caliente Band of Cahuilla Indians has been embroiled in a legal tug-of-war with the Coachella Valley Water District, the Coachella Valley’s largest water agency, and the Desert Water Agency, the water utility for the Palm Springs area, over whether or not the tribe has federally reserved rights to groundwater. Last month, a federal judge sided with the tribe, determining that U.S. government impliedly reserved groundwater, as well as surface water, for the Agua Caliente band when it created the tribe’s southern California reservation.
During the legal proceedings, the tribe expressed dismay that CVWD and DWA have been importing untreated water from the Colorado River to reduce aquifer overdraft. Tribal Chairman Jeff L. Grubbe called this method of recharging the aquifer a “detrimental practice” that has significantly lowered the water quality in the valley.
“We brought it to the attention of the water districts over and over for years, simply to be ignored,” he said following the judge’s March 20 ruling.
CVWD has a very different view of the matter.
“We have tried to explain to the tribe on many occasions that Colorado River water is not of inferior quality to the groundwater,” said Heather Engel, CVWD spokesperson. “The quality of the two sources of water are different and complementary of each other.
“In some areas of the valley, the groundwater contains naturally occurring arsenic and chromium-6 above state water quality standards,” she continued. “Colorado River water does not have these contaminants at a detectable level, therefore it helps dilute the level where replenishment occurs.”
Grubbe said this is an oversimplification of the Coachella Valley’s groundwater situation.
“It paints an unrealistically broad and rosy picture of the dilution function of the imported Colorado River water,” he said. “The aquifer geology underlying the valley is complex. Dilution of naturally occurring contaminants may occur in some locations; however, it’s a gross oversimplification to make it sound as if importing water is resolving, for instance, the chromium-6 problem that is getting worse throughout the valley.
“If that were true,” he added, “why would the water districts now be confronted with having to add water treatment capacity to deal with the chromium-6 problem all across the valley?”
Last fall, The Desert Sun reported that chromium-6 limits exceeded a safe limit recently adopted by the state, and CVWD was looking at options beyond importing Colorado River water. These included building treatment plants at all affected wells, installing reverse-osmosis filters in homes, and building treatment plants for well water together with new facilities to treat Colorado River water.
Then there is the salinity issue. CVWD acknowledged that Colorado River water does have a higher level of salt than some areas of the Coachella Valley. Natural salinity in local groundwater ranges from 130 parts per million to more than 2,000 ppm. The Colorado River water has a salinity level ranging from 550 to 750 ppm.
“There are no state or federal health standards for salinity in water,” Engel said. “California water agencies are required to meet consumer acceptance standards for salinity based on aesthetics like taste. A salinity level of 1,000 ppm in drinking water is considered acceptable by the state aesthetic standards.”
To the Agua Caliente band, however, the river water’s salinity is a major issue. Grubbe said tribal members and all Coachella Valley residents should be concerned.
“It’s also an issue from which the water districts have recently been working very hard to distract or redirect public scrutiny,” Grubbe said.
He explained that the districts have an obligation under California law to prepare a Groundwater Basin Salt and Nutrient Management Plan. SNMPs are mandated by the State of California’s Recycled Water Policy, adopted in 2009. The policy encourages the use of recycled water from municipal wastewater sources.
“The concern, however, is that recycled water, and other sources of water, contain salt and nutrients that must be managed to protect the water quality of the state’s groundwater basins,” Grubbe said. “For this reason, the policy requires the development of SNMPs to evaluate current and future projects, and ensure that basins are managed with appropriate consideration of water quality.”
CVWD’s SNMP will become the primary document under which water quality in the upper Coachella Valley groundwater basin will be managed by the state, through the Colorado River Basin Regional Water Quality Control Board. This includes the management of the aquifer underlying the Agua Caliente band’s 32,000-acre reservation — and the effect of the use of the imported Colorado River water for recharge of that aquifer.
“The tribe has criticized the districts’ draft SNMP for over-reporting the ability of the aquifer to assimilate total dissolved solids and other nutrients, and thus under-reporting the total dissolved solids and other nutrient levels found there, especially in the upper valley underneath the Agua Caliente Reservation,” Grubbe said. “The CVWD Whitewater Recharge facility is situated immediately up-gradient from the reservation, and so imported Colorado River water adversely impacts the aquifer underlying the reservation first.
“As the Colorado River water continues to be pumped into the aquifer, sooner or later all valley residents will be impacted, if they aren’t already,” he added.
CVWD maintains that such concerns are misguided, noting that more than 30 million people drink water from the Colorado River.
“Those water agencies filter the water before delivery, but they do not perform treatment to reduce salinity levels,” Engel said. “Groundwater percolation is a natural filtration process that’s more cost effective than artificial treatment processes.”
Grubbe said this avoids an important question: How is it possible to clean up all of the salts and other nutrients being deposited in the sands of the aquifer after decades of deposition?
“The troubling answer is that there is no way to clean them out of the aquifer once they are there,” he said. “The aquifer’s natural filtration process is not something you simply replace like an over-the-counter kitchen water filter that has been used for too long. It’s the duty of all valley residents to make sure that those persons who are charged with the responsibility of managing the aquifer protect the ability of the aquifer to naturally filter our water.”