Gov warns of impending flooding in Pierre, Fort PierrePIERRE — Flooding in Pierre and Fort Pierre is “imminent” and people should prepare to evacuate within 48 hours. Gov. Dennis Daugaard warned residents of the growing flooding risk Thursday. The Missouri River is rising and will soon inundate parts of both cities, the governor said.
By: Staff Reports, The Daily Republic
PIERRE — Flooding in Pierre and Fort Pierre is “imminent” and people should prepare to evacuate within 48 hours.
Gov. Dennis Daugaard warned residents of the growing flooding risk Thursday.
The Missouri River is rising and will soon inundate parts of both cities, the governor said.
Record flows into the river from Montana through South Dakota are forcing the U.S. Army Corps of Engineers to increase releases from the mainstem dams. The increased releases will raise water levels, according to the governor’s office.
Water levels are expected to rise later this week and could remain at flood stage levels into July. The Governor’s Office said property owners should plan to evacuate their property by this weekend and may not be able to return until mid-summer.
The Corps plans to increase the water release beginning on Saturday. Flooding is projected to begin on Saturday and worsen between June 4-6.
Thursday, the elevation of the Missouri River at Pierre and Fort Pierre is 1,430 feet above sea level. The elevation could increase as much as four feet as water flows increase.
Saturday, the Corp will increase water flow from the Oahe Dam to 85,000 cubic feet per second. The number will increase to 90,000 on June 4, 95,000 on June 5 and 100,000 on June 6.
As the snowmelt continues into late June and early July, the water flow will increase to 110,000 cubic feet per second and may reach 120,000 cubic feet per second.
Wednesday evening, the Army Corps of Engineers dramatically increased their calculation of water release required from the mainstem dams on the Missouri River. The Corps believes that this increased water release is necessary to avoid overtopping of the spillways.
Huge rainfalls in Wyoming, Montana, and western North Dakota and South Dakota over the past month have exceeded rainfall in a normal year. This used the reservoir capacity that had been reserved to accommodate the snowmelt. In addition, mountain snowpack is 135 percent to 140 percent of normal, and it is melting at a later time. As a result, all the moisture will require the Corps to increase water flows to unprecedented levels.
State and local officials are currently coordinating plans for shelter and assessing the potential impact on utilities and other infrastructure. Officials are also working to obtain additional flood-fighting and sheltering supplies.
Flooding is expected in the following areas:
Fort Pierre: In the area south of the Missouri River bridge and north of Cedar Avenue, everything between the Missouri River and Highway 83. In the area north of the Missouri River bridge and south of Echo Point, everything between the River and Marion Pastures is expected to flood.
Pierre: Flooding is expected to begin in the residences on either side of Marian Drive, the southeast area of Pierre and everywhere both east of Washington Street (near St. Mary's Hospital) and south of Missouri Avenue.
While the primary are of concern is Pierre and Ft. Pierre, flooding is expected to impact other communities. Information will be released as it becomes available.