A draft analysis by state water board staff suggests California American Water could legally use Salinas Valley groundwater for its proposed desalination project under certain conditions, a finding which could play a key role in resolving a major potential obstacle.

The draft report, issued Dec. 21, concludes Cal Am”s use of brackish water from shoreline slant wells north of Marina as source water for its proposed Monterey Peninsula Water Supply Project desal plant was unlikely to result in “injury” to other Salinas Valley groundwater users despite a predicted lowering of groundwater levels within a two-mile radius of the wells.

The report finds the resulting desalinated product water would likely be “surplus” to the existing supply in the seawater-intruded area and as long as Cal Am returns any “incidental” fresh water to the basin in a way that avoids injury to other users, the water project “could proceed without violating other users” groundwater rights.”

However, the report also finds it is “not possible to make definitive water rights statements at this time” because the project”s details and aquifer conditions are unverified. It suggests that Cal Am be required to prove there would be no such negative impact and that any fresh water it extracted would be returned to the basin in the most beneficial way — perhaps via injection wells, percolation basins or the Castroville Seawater Intrusion Project. It points out that more information is needed to evaluate the project”s impacts on basin conditions, and includes a series of recommendations on how Cal Am can produce that data.

Cal Am spokeswoman Catherine Bowie said the draft report is “consistent with our position on water rights” and “validates” Cal Am”s legal briefings submitted to the state Public Utilities Commission in July including the conclusion that “no water right is needed to pump seawater.”

“There are certainly areas in the report for which we will seek clarification,” Bowie said, “and we agree … that further technical study is needed in order to confirm there will be no impact to other pumpers in the basin. We believe our proposed slant test well will supply the additional information needed to resolve this issue.”

The report calls for more specific information on:

· The depth of the proposed wells and the dune sand aquifer from which Cal Am has proposed to extract feeder water.

· The extent of the dune sand aquifer and its water quality and quantity.

· The extent and thickness of the Salinas Valley aquifer, and the extent of the 180-foot aquifer.

It recommends a series of test boring/wells designed to assess the hydrogeologic conditions at the site, and aquifer testing to determine the proposed pumping”s potential effects on both the dune sand aquifer and the underlying 180-foot aquifer.

The data, according to the report, will form the basis for a plan that “avoids injury to other groundwater users and protects beneficial uses in the Basin.”

Carmel Mayor Jason Burnett, vice president of the Monterey Peninsula Regional Water Authority, said the authority”s technical advisory committee would review the draft report on Monday, and declined comment until then. The committee meets at 2 p.m. at Monterey City Hall.

Critics of Cal Am”s proposed project have suggested that it faces lengthy delays, including virtually certain litigation, over the issue of Salinas Valley groundwater rights and the project”s potential impact on seawater intrusion in the area. Some have urged the company to relocate feeder wells outside the basin.

Basin water users, led by agricultural interests, have argued use of the basin”s water is managed through cooperative agreements that would be disrupted by the proposed project and lead to a costly adjudication process.

Marc Del Piero, a former state water board member and water law attorney, pointed out that the report is a “draft” relying largely on Cal Am”s representations and is missing crucial information related to the Salinas Valley Water Project and its intent. Del Piero”s Ag Land Trust successfully sued the Marina Coast Water District over the failed regional desal project and its environmental review, including the failure to address the water rights issue.

When the Monterey Peninsula Water Management District approved spending on pursuit of an alternative desal proposal, staff cited groundwater rights as the major potential impediment to timely implementation of Cal Am”s project.

According to Michael Buckman, senior environmental scientist for the state Water Resources Control Board, water board staff is issuing the report to the public upon request, and is waiting to hear back from PUC officials before starting a noticed public comment period. He said a final report will be issued that includes public comments and responses, though there is no timeline for its completion, and a public workshop on the final report could also be scheduled.

The PUC requested the state water board”s assistance in September in reviewing Cal Am”s legal right to extract desal feeder water for the latest water supply project on the Peninsula, which is designed to provide a replacement source of water to offset a state-ordered cutback in pumping from the Carmel River that takes full effect at the start of 2017.

Meanwhile, public participation hearings on Cal Am”s proposed project are set for next week in Monterey. Cal Am has been ordered by a PUC judge to provide an update of the project description, including a number of proposed changes and other key developments, during the hearings. The hearings will be held at 2 p.m. and 7 p.m. Wednesday at Monterey City Hall.

Jim Johnson can be reached at 753-6753 or jjohnson@montereyherald.com.