SIOUX FALLS, S.D. (AP) - Emergency earthen levees built to protect southeast South Dakota from the rising Missouri River were holding back the floodwaters as increased water releases from Gavin's Point Dam began reaching the area, officials said Wednesday.
Gov. Dennis Daugaard said levees also were holding strong in the Pierre and Fort Pierre areas, where earlier releases were increased to record levels on Oahe Dam a few miles upstream.
But the governor urged residents to remain cautious, pointing to recent levee ruptures in northwest Missouri, which show the situation can change quickly.
"It reminds us that even permanent levees that were built and are more stable after years of existence can breach and do breach, thus, also may our temporary, urgently and rapidly constructed levees breach," Daugaard said during a briefing Wednesday.
The U.S. Army Corps of Engineers is pushing 150,000 cubic feet of water per second through both the Oahe and Gavin's Point dams, the equivalent of 1 1/2 times the average daytime flow rate over Niagara Falls in the summer tourism season. The goal is to get rid of unexpectedly heavy rains that fell last month upstream in eastern Montana and Wyoming and western North Dakota and South Dakota.
LeeJay Templeton, a corps engineer, said that in an average year, about 4 inches of moisture from snowpack above the Fort Peck Dam in Montana would be poised to come through the river system.
This year, about 13 inches of moisture is ready to enter, he said.
Daugaard said the state is slowly scaling back its force of over 1,000 South Dakota National Guard soldiers helping with the flood response, as sandbagging and traffic control demands have ebbed.
He said the Guard's primary role will continue to be levee surveillance.
"We have daily levee issues that arise - plastic repair, foil repair, groundwater issues - that the guard is alert to and alerts the quick response force to address," he said. "In some cases we arrange for private contracts to manage further. In other cases the Guard is able to address it completely."
A Chinook helicopter that had been airlifting sandbags to flood zones was sent home to Illinois, but the Guard will keep a pair of hoist-equipped Black Hawk helicopters on standby in Pierre and Dakota Dunes in case someone needs to be evacuated in an emergency.
Jeff Dooley, the Dakota Dunes community development district manager, said with that town's levees built, the community is shifting into a monitoring stage. Officials held a meeting with residents to outline a credentialing system that will be used to give them access to their homes beginning Thursday.
About half of the Dunes' 2,500 residents have been evacuated.
In Pierre, Mayor Laurie Gill said the city is starting to take ownership and control of the levees over from the corps. She said the dikes continue to pass inspection.
"We are monitoring them regularly," Gill said. "They are holding, but they are levees and they are temporary."
Daugaard said South Dakota to date has spent more than $10 million on its flood response, with more than $5 million of that spent on the Guard activation. The figure does not include costs incurred by the individual communities, he said.
The governor urged residents to put safety first and asked that those needing to access their evacuated home or business do so only during daylight hours and do not stay overnight.
"Watch your children and keep them away from the river," Daugaard said.