Rising Missouri River water levels put Bismarck, Mandan on alert
BISMARCK—While Missouri River levels hadn't yet fully risen Wednesday afternoon, the water was coming.
Levels were expected to reach the 12-foot stage overnight near Bismarck as the U.S. Army Corps of Engineers increased water releases out of Lake Sakakawea for yet another time this season.
Water released through the Garrison Dam went from 44,000 cubic feet per second to 52,000 cfs, or 388,987 gallons per second, and is expected to continue at that rate through mid-July.
Lake elevation is expected to peak near 1,852.5 feet in the next two weeks as runoff from the remaining mountain snowpack in Montana tapers off. Remaining snowpack water equivalent is less than 2 inches, the corps reported Monday.
Emter said, while there is no way to control the weather and the rain that fell over the lake this past weekend, what has been difficult is how many times the corps has readjusted its predictions.
In its two lake marinas, Lake Sakakawea State Park and Fort Stevenson State Park, North Dakota Parks and Recreation has asked owners to remove bigger boats housed there.
"Those larger boats tend to catch a lot of wind," said Assistant Director Jesse Hanson, adding that they are sitting at an even higher elevation with the raised water levels.
Along the river, Hanson said they've had to pull the courtesy dock at Sanger Boat Landing near Cross Ranch State Park and boaters are warned that the higher flows will likely make launching a boat more difficult at that location. Due to the more dangerous launch conditions, Hanson said Cross Ranch has also discontinued its canoe and kayak rentals.
At Fort Lincoln State Park, no flood impacts beyond some possible groundwater seepage are expected at this time, Hanson said.
Bismarck city officials have been put on notice, as is required by the city Flood Response and Action Plan. Public Works Director Jeff Heintz said some minor preparations have been made but no major response is needed unless the river stage reaches 16 feet.
"The big unknown is rainfall," Heintz said.
In 2011, major storms in eastern Montana dumped a season's worth of rainfall on the area in the span of a couple weeks, which pushed the Garrison Dam over its capacity.
Since then, Bismarck has constructed more protection measures. The flood also changed how the river moves water through the area, Heintz said. A deeper channel was cut, increasing the amount of water that can pass, so, at the current release rate, the river stage now is different compared to the stage during these same rates in 2011.
"Morton County officials want to assure residents along the Missouri River that residential impacts from increased flows and higher water levels should be minimal," the county said in a statement Tuesday. "Any flood concerns which may occur are anticipated to be well within local capabilities to manage. While observations of higher water and possible increases in sump pump activity may create some anxieties, actual outflows and anticipated stages downstream are not of a magnitude to translate into significant widespread impacts."