Community Of Oasis Question Water Safety. Water from the Colorado River is what made life and farming in the rural, east valley community of Oasis possible.
On Thursday, the people of that community questioned whether the water that provides jobs here is safe to drink.
The answer has implications for the entire Coachella Valley.
About 60 people crowded a bilingual meeting of the Oasis Community Council in response to reports from a nearby Indian tribe that a chemical used in rocket fuel is contaminating east valley groundwater wells.
The chemical, perchlorate, was detected in a well on the tribe’s reservation in the fall. Since then, tribal officials have conducted more tests.
The tests show levels above the state’s “action level” for public notice.
There is no evidence, however, that the chemical has caused health problems for local residents.
“A lot of us are drinking water from our wells. We don’t know what is in there,” council member Anna Rodriguez told officials from the Coachella Valley Water District.
Locally, perchlorate is thought to have arrived via canals that connect the Coachella Valley to the Colorado River.
In the past, river water has been used locally mostly for crop irrigation.
However, now that population growth is depleting the valley’s groundwater supply, the water district plans to subsidize the underground aquifer with water from the river.
“Colorado River water is essential,” said Steve Bigley, a water quality specialist for CVWD. “There is no other feasible source of water for the Coachella Valley.”
Currently, California requires the public be notified if perchlorate is detected at a level of four parts per billion or greater.
In 2001, CVWD closed a “low quality” well in La Quinta after detecting a level of about 5.5 ppb, although it was not required of the district.
Perchlorate Has Been Detected
So far, the well in La Quinta and “more than three” wells on the Torres Martinez reservation are the only sites where perchlorate has been detected, tribe officials said.
Torres Martinez officials have said results from a well near a small tribal community in Thermal show a level above 4 ppb.
The tribe is concerned that future groundwater recharge plans by the water district could exacerbate the problem.
Groundwater recharge involves injecting river water into the ground where it mixes with the existing aquifer.
“We have a problem, and we need to start looking for a solution,” said Alberto Ramirez, a tribal environmental official. “We don’t pollute the water. Why are we going to pay for the consequences?”
But treating all the Colorado River water imported to the valley is expensive.
To reduce perchlorate to non-detectable levels in imported river water would cause water rates to double, according to CVWD. And that doesn’t include the cost to dispose of the filtered material, Bigley said.
Both Bigley and Steve Robbins, interim general manager of CVWD, said the outcome of a decision by the state to implement new standards will determine whether CVWD ratepayers will bear the burden of treatment. The state is considering action levels between two and six parts per billion.
A final decision is expected by early 2004.
Treating water for perchlorate can cost about $230 per acre-foot.
The Coachella Valley imports about 330,000 acre-feet of river water annually, but river water is not widely used here for drinking. It also is unlikely the entire supply of imported river water would require treatment, according to CVWD.
Bigley said deciding how to address the problem locally will depend on more studies and future drinking water standards. Perchlorate has only been considered a problem since the mid-1990s, and almost nothing is known about its long-term effects on humans.
“Everything is poison — sodium, calcium, everything. It is the dose that determines whether it is safe or not,” Bigley said.
“If the benefits are small and the costs are very high, it may not be practical to treat at that low level.”