Work is ongoing to repair the drain that regulates the water level at Beaver Creek Reservoir south of Havre, with the Hill County Commission receiving an update Wednesday on one component of that work.
Work has been completed to reconnect the gate to its framework and open it, allowing the dam regulator to drain water and reduce levels of the reservoir as needed.
Commission Chair Mike Wendland said the state Department of Natural Resources and Conservation briefed the commission about repairing a hydraulic cylinder that opens and closes the gate. The commission will receive bids on the costs to either repair or replace the cylinder, he said.
The problem came to a head this summer during high runoff in the Bear's Paw Mountains that led to a federal disaster declaration due to flooding. While the gate, used primarily to release water for irrigation and to control the level of the reservoir, was being tested, it stuck closed.
That kept the county from releasing water and reducing the level of the reservoir, leading to concerns that spring runoff in 2011 could cause water to overflow the dam.
Wendland said two large bolts that connected the gate to its framework had sheared off, causing it to drop to a closed position. That also led to damage of the hydraulic cylinder used to open and close the gate.
Divers from Associated Underwater Services of Spokane determined the problem, reconnected the gate and brought the cylinder up for inspection and possible repair.
Wendland said a company in Billings is determining how much damage happened to the cylinder.
He said the total cost of the operation is not known as yet. The Spokane company broke down their portion of the project into two parts, the inspection and the repairs, and has not yet billed the county for the second phase.
Payment for the project will come from a renewable resource grant originally provided to the county to upgrade a berm below the dam. As that project has been reduced in scope, Wendland said, the county intends to use leftover funds from that grant to pay for the repairs to the gate.
Work on the project to upgrade the berm and to drill observation wells to measure and release water pressure on the berm is expected to begin later this year.
The dam, built in the 1970s for flood control, storage of irrigation water and recreation, is owned and operated by the county. It was designed by the federal Natural Resources and Conservation Service of the U.S. Department of Agriculture. NRCS also helped provide funding for the construction and is involved in oversight of its operations by the county.
The state Department of Natural Resources and Conservation also provides oversight. DNRC issues the permits to allow the dam’s operation.
The drainage system is composed of the upper gate, about 400 feet upstream from the dam, and a compression chamber at the dam itself. Two gates at that chamber are used to regulate the water flow out of the dam.
The upper gate is used to shut off the flow, allowing work in the compression chamber.