On Thursday, June 2, the Oahe Dam near Pierre released an average of 85,000 cubic feet of water per second (cfs). On Friday, that level approached 100,000 cfs. By the end of this week, it promises to reach 150,000 cfs.
Previous to this, the record release was 59,000 cfs.
Pierre/Fort Pierre for the last week have been racing, said Gov. Dennis Daugaard. About 2,000 homes have been evacuated as the Oahe rises, and even as I speak there are heavy equipment operators trying to build levees to protect the towns.
The governor stopped to give a presentation at 2011 South Dakota Girls State in Slagle Hall at the University of South Dakota last Friday, after which time he went to Dakota Dunes, another site of the approaching flood.
Of the approximately 1,100 homes in Dakota Dunes, probably 800 to 900 of them are in danger of flooding, Daugaard said.
There are crews working 24 hours a day, around the clock, to build the levees up. Were building some levees up six to eight feet, he said. I dont know if well get them built in time, or if we get them built, built whole. So there are thousands of South Dakotans who are scrambling to protect their homes, because they can see this water coming.
Traffic was shut down Thursday to assist in evacuation and construction of the levees, a measure Daugaard expected to continue at least through Friday.
There are fewer and fewer and fewer people in Dakota Dunes as people are evacuating, and our goal is to get to 1,100 height on the levee upstream and downstream, he said.
Daugaard said he has been asked many times over the course of the past week whether the approaching flood which promises to raise the level of the river three to four feet is the result of faulty planning on the part of the U.S. Army Corps of Engineers.
Simply put: No.
Its Mother Nature thats bringing this upon us. Not man, the governor said.
As of May 1, Corps data indicated that all reservoir levels were normal, Daugaard said. However, snow continues to accumulate in the Rocky Mountains and rainfall up-river has been much higher over the past two weeks.
There were parts of the Black Hills that got 10 inches of rain. There were parts of Montana that got 15 inches of rain, Daugaard said. Ten and a half million acre feet of water fell. That means 10 acres of land covered by a foot (of water). Thats how much rain fell in about two weeks.
Thats 130-140 percent above average, he said.
Added to this, the snowpack in Montana has not melted to any great degree.
I talked to (Montana Gov. Brian Schweitzer) yesterday, and he said, The Yellowstone River in Montana normally peaks its flow the second week of June. Its been out of its banks for two weeks, and the snowpack hasnt even started yet, Daugaard said.
As a result, the reservoirs are now full.
The Oahe reservoir is about a foot from the top, Daugaard said. I think its less than a foot from the top. If its windy, it blows over the spillway.
The governor inspected the levees in Pierre/Fort Pierre before he left for Vermillion Friday morning, and said theyre looking good.
Were in very good shape in terms of elevation, and the water wont get to 150 for another week, so I would say a day or two well be done everywhere in Pierre and Fort Pierre, he said. As the contractor realized that they were able to accomplish so much, theyve extended the dike northward and tried to protect more homes. So, theyre working on an enlarged project.
Once construction is complete, the mission will shift to the surveillance of the dikes and protection of the neighborhoods, including providing emergency response if problems are detected, the governor said.
Were going to be keeping Black Hawk helicopters at both Pierre/Fort Pierre and at Dakota Dunes so we can do emergency evacuation of individuals who have otherwise refused to leave and now need to because of a dike or a levee issue, he said.
These helicopters can lift between 1-2 tons and can bring in rocks or sand if there is a breach that can be plugged, Daugaard said.
Theyre the finger in the dike, he said.
Overall, the work has gone well.