Flooding of the Missouri River along the western edge of Iowa this summer has forced hundreds of families from their homes, flooded many farmsteads, drowned an estimated 150,000 acres of crops, closed highways and bridges and caused other on-going aggravation and economic loss.
The U.S. Army Corps of Engineers announced last week that residents, business owners and farmers weary from the massive flooding will have to wait until late September or early October for the Missouri River to return to its banks.
Releases of water from Gavins Point dam near Yankton, South Dakota, began being lowered this past weekend. But it will take a long time for the water that’s now on farm fields and in rural areas to recede, so the river level won’t change very quickly, says Paul Johnson, spokesman for the Corps’ Omaha district office.
Corps has to reduce the flow of water slowly, to avoid levees breaks
Gavins Point is the last of the six big reservoirs and dams on the Missouri River which regulate the flow of water downstream. The Corps has to reduce the flow slowly, he says. If they let the water out too fast, levees risk breaking as the water falls. If the water level drops slowly, levee sections can dry and stabilize.
The Corps began lowering the amount of water released from the dam on July 30. The snowpack in the Montana mountains is gone, and the amount of water entering the upstream reservoirs has decreased significantly.
Releases from Gavins Point have been lowered from 160,000 cubic feet per second to 155,000 as of July 30. On August 1 the rate was dropped to 150,000. That is the same rate as when the flooding began earlier this spring. It is more than twice the amount of outflow as the previous record release of 70,000 cubic feet per second set in 1997.
Once the water recedes, officials will be able to fully assess damage
The rush of water has tested Iowa towns’ flood protection efforts, and many towns built temporary levees or added to existing structures to prepare for this summer’s flooding. Then heavy rains boosted the Gavins Point dam release to 160,000 cubic feet per second. That came as tributaries to the Missouri River were adding less of a load due to declining rainfall, so the river level has changed very little in recent weeks along the Iowa side.
Once the flood water recedes along the Missouri River, farmers, residents, businesses and government officials will be able to assess the full extent of the damage and plan repairs. On the Nebraska side of the river, that state’s two nuclear plants that generate electricity have been shut down during the flooding this summer. Omaha Public Power District officials say they are uncertain how soon the plants will be able to restart generating electricity.