LINCOLN CITY, Montana - Yesterday, just after midnight, a 5.8 magnitude earthquake was reported near Lincoln City, Montana. The earthquake was centered approximately 140 miles from Como Dam, located in Ravalli County, Montana, near the town of Darby. Como Dam is owned and operated by the Bitter Root Irrigation District. The Bureau of Reclamation, however, has oversight responsibility for the structural safety of the dam.
“In accordance with Reclamation’s earthquake reporting procedures, the earthquake triggered notification from U.S. Geological Survey to Reclamation," said Jim Dean, supervisory civil engineer with Reclamation’s Pacific Northwest Region. “Our reporting procedures prompted us to notify the Bitter Root Irrigation District the earthquake was in the proximity of the epicenter and required an immediate inspection of Como Dam."
Bitter Root Irrigation District dam operators inspected the dam at 2:30 a.m. and determined there was no visual damage or changed conditions of the dam or any of the associated structures. Further inspections of the dam continued at daybreak where all monitoring instrument readings were taken and all features of the dam were inspected in detail. Inspections confirmed the dam and associated structures did not receive damage from the earthquake.
“Dam safety is a top priority for the Bureau of Reclamation," said Dean. “We take these inspections very seriously and ensure they are thorough and detailed."
Como Dam was completed in 1910 by local irrigators and rehabilitated on its crest and upstream face by the Bureau of Reclamation in 1954. This semi hydraulic earthfill dam at the end of a natural lake is 70 feet high with a crest length of 2,550 feet and contains 1,114,000 cubic yards of earth and rock.
Source: Bureau of Reclamation
