Road will be breached to alleviate flooding worries

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MILFORD, Iowa — The U.S. Army Corps of Engineers will order the breaching of 230th Avenue between Lower Gar Lake and its Mill Creek outlet after the Little Sioux River crests and begins to go down, possibly Sunday but more likely Monday.

At that point, contractors Soukup Construction of Sioux Falls, S.D., will have 72 hours to complete the project, breaching the road with a 50-foot opening and riprapping it for protection against scouring and erosion.

“We expect that the river levels downstream will increase by .03 to .09 of a foot,” said Paul Johnston, Chief of Public Affairs for the Omaha District of the Corps of Engineers.

Waiting a few days would ensure there would be enough room in the river for the small amount of extra water.

“The crest should go by, and this will be just a very small filling behind it,” Johnston said.

Though the move is anticipated to have only a small effect on the river, it should reduce the peak level of the water on Lower Gar Lake by 1.1 feet.

“It will take the lake down, to stay within ordinary high water,” said Dickinson County Engineer Dan Eckert. “The ordinary high water mark on the lake is 30 inches above the existing dam on Lower Gar Lake.”

Soukup Construction will remove four of the existing eight 48-inch-equivalent elliptical arch pipes that, along with a 12 foot by 5 foot emergency culvert put in place in 1993, drain water from Lower Gar Lake into Mill Creek and from there, the Little Sioux River.

The county may save the pipes in order to put them back in after the road is reconstructed, Eckert said.

Instead, however, the county may opt to replace the eight small culverts with larger, box culverts, Johnston said.

The breach will cost $69,000 in federal funds, and Dickinson County will pay approximately $15,000 to $20,000 for the road to be restored.

The project has met with some opposition from local landowners, who worry about the water becoming too shallow to navigate by September if too much water is let out of Lower Gar Lake, and say toxic blue-green algae becomes a problem when the lake is low.

Eckert, however, said lakeshore property owners with low banks on the lake were the people most likely to benefit from the lake being drawn down, because their property would then be less likely to flood.

Tags: state and region, lower gar lake, news, iowa, milford, flooding