Pipestem spillway drained for inspectionIf the level of the Pipestem Reservoir looks a little low these days you’re right. The lake level has been drawn about a foot below the normal fall level to allow for cleaning on the main spillway structure on the dam’s backside, according to Bob Martin, dam manager.
By: Keith Norman, The Jamestown Sun
If the level of the Pipestem Reservoir looks a little low these days you’re right. The lake level has been drawn about a foot below the normal fall level to allow for cleaning on the main spillway structure on the dam’s backside, according to Bob Martin, dam manager.
“We haven’t de-watered the stilling pond since 1995 although we had divers looking at the structure about five years ago,” he said. “This gives us a chance to inspect the entire structure.”
By lowering the level of the lake, the flow of water through the spillway can be stopped. With the flow stopped the level of the water in the spillway dropped exposing rocks that had worked their way back from the stream into the spillway structure.
“The water rolls so quickly as it comes out the action carries the rocks,” Martin said. “The rocks can be moving so fast they pulverize concrete if they hit the structures.”
The main spillway is the normal means of releasing water from the reservoir, as opposed to the emergency spillway near the west side of the dam.
Local crews had been clearing the rocks, mud and accumulated fish — including some 10-pound walleyes and 15-pound northern pike — away from the spillway. Engineers from the U.S. Army Corps of Engineers will inspect the spillway and the conduit, an 8-foot diameter pipe, leading from the drain structure in the lake to the spillway below the dam.
“We expect the lake to keep gaining a little bit from ground water and any fall rains we get,” Martin said. “Sometime this fall it will gain back that foot and then we’ll start letting water through the spillway to keep it at that level.”
Sun reporter Keith Norman can be reached at (701) 952-8452 or by e-mail at firstname.lastname@example.org