WENATCHEE — Studies to determine how strong an earthquake could potentially shake Chelan County PUD dams will continue with an injection of fresh funding.

Commissioners on Monday approved the final $240,000 of a total $500,000 contract for the federally mandated seismic studies, which began in mid-2006.

Gene Yow, civil engineer for the utility, said this phase of the work involves reviewing studies already compiled by the U.S. Geological Survey and other researchers on mapping area faults and records of past earthquakes in the area.

“They want us to be sure we don’t get any nasty surprises,” he said of federal dam regulators.

Yow said the work will more accurately determine how strong an earthquake the dams should be prepared for.

The study includes the geology around all three Chelan PUD dams, Lake Chelan, Rock Island and Rocky Reach.

He said older estimates tended to overstate the strength of potential earthquakes in North Central Washington.

Chelan, Douglas and Grant PUDs are doing the studies simultaneously, but each with their own consulting firm, Yow said.

The consultants are sharing information and working together, Yow said.

The Chelan County PUD contract with international engineering firm, URS Corp., is expected to last another two years.

When it’s finished, PUD engineers will take the collected data and create a computer model that tests the dams under different strengths of quakes.

The computer tests will show if any of the dams’ components need to be strengthened, he said.

He added that engineers don’t anticipate the studies will show a need for major strengthening work.

Christine Pratt: 665-1173

pratt@wenatcheeworld.com