Libby Water Project to Begin This Spring

A $12.4 million water system improvement project will begin this spring with the replacement of more than 7,000 feet of distribution pipe under the city of Libby. The largest part of the project, the replacement of the Flower Creek Dam south of town, will be put out for bid late this year and completed in 2014.

Engineers with Morrison-Maierle, Inc. of Kalispell have begun designing a new gravity dam that will be constructed 85 feet downstream from the current one. Those preliminary plans will be submitted to the Montana Department of Natural Resources and Conservation for approval next month.

The Flower Creek Dam was completed in 1946 and has deteriorated considerably in recent years. In 2010, Morrison-Maierle completed a core sample test of the arch dam and found that the concrete strength was less than 1,000 pounds per square inch. Normal strength is between 3,000 and 4,000 pounds per square inch.

“We have watched and monitored the dam for several years and it continues to deteriorate,” said civil engineer Paul Burnham. “The state has indicated that it will likely not renew the permit for the dam for another five years.”

DNRC last issued a five-year operating permit for the dam in 2010. A report, issued by Morrison-Maierle in September 2011, stated that under normal conditions the dam would be useable for another five years, however if there was a seismic event the dam could be compromised, flooding Flower Creek and Libby.

Although engineers and city officials say it is unlikely that the dam will break, Lincoln County did install a new sensor and alert system at the dam. If there were a sudden drop in water behind the dam, 911 dispatchers would be notified and could view images of the site to determine if a siren needs to be sounded in the city.

The 2010 core tests show that the dam’s concrete has grown weak and that water is seeping through. Last year, engineer Ryan Jones hypothesized that during construction builders used too much water. He also said that the concrete may have never fully settled before it froze during the winter following the dam’s construction.

The new dam is estimated to cost $8.4 million, part of which will be covered by a $7.1 million USDA Rural Development grant and loan. Additional funding is anticipated from the Community Development Block Grant program.

Before work can begin on the dam, Libby must replace and update parts of its water distribution system. Work on that project is expected to start this spring and will cost more than $4 million, part of which will be covered by another USDA Rural Development grant and loan package.

According to Burnham, more than 7,600 feet of water pipe will be replaced in Libby. The project will also add 3,100 feet of new pipe and five new pressure reducing stations, that will allow the city to boost water pressure in some areas.

In 2011, the Libby City Council decided to move forward with the construction of a new Flower Creek Dam. Mayor Doug Roll said replacing it made more sense than a temporary fix.

“Anything like this will be a definite boost to the economy,” Roll added.

For more information about the water improvement project and dam replacement, visit www.libbywaterprojects.com.