State and local officials are monitoring conditions at Tolna Dam in Nelson County. Bruce Englehardt is director of water development for the State Water Commission. He says a hole has opened in the concrete spillway of the dam putting it at risk of failure.
“…I’m not even sure how big the hole is because it’s underwater at this point. You can see the water – instead of flowing across the spillway and down the chute – it’s at like 90-degrees from the direction it should be going into the dam and going down.”
Englehardt says the Tolna Dam is an earthen embankment with a concrete chute spillway structure. He says emergency plans are in place should the dam give-way over the weekend. Englehardt says mapping shows NO HOMES would be inundated if there is a failure…
“…North Dakota Highway 15 is immediately downstream from the dam. It would certainly be impacted. There aren’t a great deal of impacts as you move downstream from Highway 15, because as the water moves downstream it will spread itself out. And so the further downstream you get, the less water elevation you’ll have. Lake Ashtabula, which is on the Sheyenne River downstream, has enough storage capacity available in it right now to catch the water from Tolna Dam eight-times over.”
Englehardt says plans to repair the dam will be made when the water level drops low enough and crews can inspect the hole and any other damage.
