Steep Hills In Boise Need Dams Fire-Damaged Slopes Won’t Hold Moisture

Flood control experts say dams must be built in drainages in the foothills north of Boise, to cut the possibility of flood damage in the event of heavy rain.

The Eighth Street Fire in August burned 15,300 acres in the steep foothills above the city. Flood control efforts, which are expected to cost up to $10 million, have been under way since then.

Experts predict that if the area gets rainfall approaching 0.4 inches in an hour, flooding is likely because fire-damaged slopes will be unable to hold the moisture.

Many public buildings in the Capitol Mall below the foothills have been sandbagged against the possibility of flooding, and homeowners have been urged to take precautions. Sandbags are in readiness around the Statehouse.

Boise will hold a meeting Dec. 9 to hear what flood control measures should be undertaken.

Some sort of dams are necessary, said assistant city engineer Ron Redmond.

“We’re going to allow the public to provide us their comments and input on what they think good solutions are for flood control in the foothills,” he said.

Redmond said nothing has been ruled out, but dams in Cottonwood, Stuart, Hulls and Crane gulches probably are the only way to prevent heavy flooding in north Boise.

Dams could cost $5.5 million, 75 percent covered by the National Resources Conservation Agency.

A dam in Cottonwood Gulch has the support of St. Luke’s Regional Medical Center. In October, President Ed Dahlberg pledged $25,000 toward flood control efforts. Bill Bodnar, vice president of corporate relations, said the hospital has spent about $100,000 on barriers to protect buildings.

If dams are the best solution, the size and number of structures will have to be determined. Redmond said dams would be built as low as possible inside the gulches.