To Save Salton Sea, Engineers Consider Dividing It in Two With Causeway

Farmers, environmentalists and water experts have tussled for decades over what to do with the Salton Sea, the malodorous saltwater lake fed by agricultural runoff that is also an oasis for millions of birds and fish.

The latest challenge is how to preserve the wildlife habitat while reducing the amount of water that supports it, which is required by a recent pact involving nearby Imperial Valley farmers, the city of San Diego and the federal government.

Now, some engineers may have a solution: slicing the huge lake in two.

The engineers have been trying to determine whether they can build a causeway that divides the lake into a cleaner, less salty lake to the north and a saltier, drier lake to the south.

A new engineering study by consultants to the Salton Sea Authority suggests that building a causeway across the lake is technically feasible, despite soft lakebed soils.

“It’s counterintuitive. It’s engineers saying we can build on peanut butter,” said Tom Kirk, executive director of the Salton Sea Authority, which commissioned the 399-page study, along with the U.S. Bureau of Reclamation.

The authority -- made up of local governments and water districts -- will meet April 22 to review potential plans and cost estimates. It may choose a plan at that time, Kirk said.

The effort has taken on new urgency because of recent reports of a sharp decrease in the lake’s fish populations.

The Salton Sea, the state’s largest lake, is actually a 360-square-mile agricultural sump fed by water from Imperial Valley farm fields.

It was created in 1905 when the Colorado River broke through a canal and filled a basin called the Salton Sink.

The high salt content of its waters allowed ocean fish to flourish, attracting 400 species of birds and making it an important stopping point on the Pacific Flyway.

But a landmark pact allowing Imperial Valley farmers to sell some of their water to San Diego will sharply curtail the amount of runoff flowing into the Salton Sea. The pact allots $300 million to ensure the bird and fish habitat is not destroyed by the loss of water.

Some experts believe a causeway dividing the Salton Sea is the simplest and most effective way to protect the interests of all concerned -- birds, fish, sports fishermen and boaters.

Preliminary results of a geotechnical study, prepared by URS Corp. of San Diego, were issued in late February.

A group of 15 civil and geotechnical engineers reviewed those results at a March 23 meeting, concluding that a dike, dam or causeway could be built on the lake, Kirk said. The group is now preparing cost estimates and recommendations for the authority.

The implementing legislation of last year’s water pact directs the state to undertake restoration of the lake.

Still unclear is how the state would work with the Salton Sea Authority on the project.

A spokesman for the state Resources Agency in Sacramento could not immediately say Tuesday how his agency would deal with the new engineering reports.