‘Dry dam’ project waits for North Dakota's OK
FARGO – A “dry dam” on the upper Maple River has federal approval, and the OK from state officials is expected soon for the $8 million project.
The dam will be located on the Maple River about
15 miles northwest of Page and southwest of Hope inside Steele County. It will replace the smaller Sussex Dam, located about two miles upstream.
A construction permit from the North Dakota State Engineer’s Office could come by September, officials said. With that permit in hand, the project can be let for bids, with completion by December 2015, if all goes well.
“We think we have all the information needed for the permit,” said Bruce Engelhardt, the state’s director of water development. “It’s still being reviewed.”
The dam will feature an embankment 5,000 feet long, or almost a mile, that will be 35 feet high and 20 feet wide. It will be capable of storing 9,950 acre-feet of water in a 925-acre pool, according to specifications by Moore Engineering, which designed the project.
As a so-called “dry dam,” the impoundment will allow water to pass through a pipe at the base, enabling a partial river flow, and the reservoir will fill temporarily during floods.
“Fish can go all the way upstream on the new dam,” said Jurgen Suhr, vice chairman of the Maple River Water Resource District.
The project is spearheaded by the Maple-Steele Joint Water Resource District.
Once the Upper Maple River Dam is complete, the Sussex Dam will be cut in the center to allow water to flow freely and fish to migrate, he said.
Flood-reduction benefits of the dam will be primarily local, protecting farmland in the area prone to frequent inundation, with negligible benefits farther downstream.
“Most of the benefit would be just below it,” Suhr said. “You’d notice some in Fargo, but very little.”
Mike Opat, the engineer for the project, agreed.
“The primary purpose is to protect agricultural land and roadways and infrastructure immediately downstream of the dam,” he said.
The dam has a flood peak reduction of 86 percent in a 100-year, 24-hour rainfall and 58 percent in a 100-year snowmelt, according to Moore Engineering.
The floodplain protected by the project is 22,365 acres.
By comparison, the Maple River Dam, a dry dam northeast of Enderlin completed in 2007, can hold 60,000 acre-feet of water from a 902 square-mile drainage area.
The Maple River flows into the Sheyenne River, which joins the Red River near Harwood, downstream from Fargo-Moorhead.
The project will receive $705,000 from the Cass County half-cent sales tax for flood control, the primary local funding sources for the planned Fargo-Moorhead diversion project.
Last year, the sales tax generated $15 million, according to figures from the Cass County Auditor’s Office.
The flood tax contributed almost $6.3 million last year to the Diversion Authority and $494,144 to other county projects.
The North Dakota State Water Commission will contribute $3.8 million toward the Upper Maple River Dam, with the Red River Joint Water Resource District adding $2.6 million.
Property owners benefiting from the dam will be assessed $850,000.
Project backers will meet with officials of the Natural Resources Conservation Service to determine whether programs under the new farm bill can be used to help pay for the dam, Opat said.
The Diversion Authority has not been asked to contribute, Opat said. The Upper Maple River Dam first was proposed, in somewhat different form, in 1996.