Engineers with Morrison-Maierle, Inc. of Kalispell and the city of Libby are moving forward with plans to replace the Flower Creek Dam just north of Libby. A road is being constructed to bring equipment to the dam site, so engineers can inspect the surrounding area and begin designing the dilapidated dam’s replacement.
Originally built in 1946, the dam holds back the Flower Creek Reservoir, which supplies Libby with water. In 2010, concrete core samples were taken from the dam and it was found to be slowly deteriorating. The strength of the dam’s concrete was less than 1,000 pounds per square inch; normal strength should be 3,000 to 4,000 pounds per square inch.
A report issued after the 2010 inspection said under standard operation the dam would be useable for another five years but could be compromised if there is a seismic event. Earlier this spring a sensor and alert system was installed on the dam to warn area residents if it fails.
“There’s no immediate threat of failure under standard load conditions, ” Ryan Jones, civil engineer with Morrison-Maierle, said earlier this year. “However, the risk of failure will increase over time.”
Libby Mayor Doug Roll said a series of public meetings have been held to discuss the dam’s future. At those meetings, members of the public have questioned whether the city should replace the dam at an estimated cost of $7.5 million. A final price tag will be known once the site downstream from the dam is studied and engineers are able to design the new dam.
“Everything has been preliminary, mostly projected cost and once we look into it we’ll have more firm figures,” Roll said. “Once we get a more solid idea of how much it’ll cost, we’ll be able to go to the Legislature for funding.”
Roll said it’s unlikely the city would be able to get enough state and federal grants to cover all of the costs, so he anticipated Libby’s water fees would have to rise. Currently, the base rate is $26 per month but Roll said it could rise by $8 in the next few years.
Opponents of replacing the dam have shared their opinions at recent public meetings. Roll said some have suggested Libby go to an underground well system, but he said that idea was studied in the past and deemed too expensive. Others have asked about repairing the current dam, but the mayor said that would only be a temporary fix.
“It’s something folks would have to deal with 25 years from now and it’ll probably be cheaper if we (replace) it now,” he said.
Once the new dam is designed it is expected to take up to two years to construct.
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