Coachella Valley targets well rehabilitations to bypass multi-million-dollar Chromium-6 treatment plant

Coachella Valley targets well rehabilitations to bypass multi-million-dollar Chromium-6 treatment plantThe California utility is soliciting bids to modify screen intervals on two La Quinta wells, aiming to block deep-aquifer Chromium-6 contamination and bring the water into regulatory compliance without building new treatment infrastructure.

The CVWD board approved soliciting bids for a well rehabilitation project with an expected budget of $800,000.

The project targets two wells currently testing at 11 and 12 parts per billion for Chromium-6.

By blocking lower well screens, the district aims to avoid constructing a planned treatment plant, potentially saving millions of dollars.

The Coachella Valley Water District (CVWD) Board of Directors voted on September 9 to approve the solicitation of bids for a well rehabilitation project aimed at reducing Chromium-6 concentrations in the Lower La Quinta Pressure Zone. The project, which has an expected budget of $800,000, will target Well 5711-2 and Well 5727-1. If the mechanical modifications are successful, the district will be able to cancel a planned multi-million-dollar treatment plant that was originally slated to serve the area. Glen Luby, acting engineering manager for domestic water, explained that the district's strategy involves isolating and blocking off lower well screens—often situated below 1,000 feet—where Chromium-6 concentrations tend to be highest. Simultaneously, crews will clean the upper screen areas to maximize the contribution of compliant water. "If successful, like we were at the other well in that area, we would be able to remove the need for a treatment plant in the La Quinta area, which would save millions of dollars," Luby told the board. The two targeted wells currently test at 11 and 12 parts per billion (ppb) for Chromium-6. CVWD has already proven the screen-modification concept at three other sites. At the nearby Well 5725, the district successfully reduced concentrations from 15 ppb to below the maximum contaminant level. A similar intervention at Well 5718 dropped concentrations significantly from 19 ppb to 12 ppb, though it remained slightly out of full compliance. The current rehabilitation package is allocated $550,000 in the current fiscal year. Luby noted that because the screening technique is highly cost-effective compared to traditional water treatment, staff will evaluate additional non-compliant wells in the district's portfolio for similar interventions once this phase is underway.