Temporary Repair Made On Dam Pipe Installed To Route Water Around Leaking Spillway

Engineers hope temporary arrangements at a spillway will prevent further damage to a dam at the Troy Reservoir.

Terry Howard, Moscow engineer, said a two-foot-diameter pipe was designed to carry water away from a break in the spillway and prevent further erosion.

“Its purpose is to carry water from the upstream side of the dam to the downstream side,” Howard said.

The break was discovered Sunday by a snowmobiler. The dam is on Moscow Mountain above Big Meadow. The Troy City Council declared a state of emergency Monday and engineers have been working since to save the reservoir.

More than half of the water in the reservoir was lost because of the break. The reservoir holds about 8 million gallons, but there was no estimate of how much water it held before the break.

Howard speculates high runoff between Thursday and Sunday could have caused water to leak under or around the spillway.

The dam, about 45 feet high, was last inspected in 1993 and was due to be reinspected this year. The dam was constructed in 1950 and raised to its present height in 1969.

Troy has applied for a $100,000 emergency grant from the Idaho Department of Commerce, but Howard said that by the time a permanent solution is completed, it may cost up to $200,000.