PIERRE -- Inch by inch, the rising Missouri River crept up into the sister cities of Pierre and Fort Pierre on Friday, as residents, National Guard crews and volunteers hurried to build and fortify earthen levees and sandbag berms against unprecedented flows from Oahe Dam.
Most of the 3,000 people thought to be in the flood zone in the two communities had already followed the voluntary evacuation request of Gov. Dennis Daugaard and other officials. And the bulk of those who remained were on alert for quick departure if the barricades against the water began to fail or the rising water took an unexpected turn, Fort Pierre Mayor Sam Tidball said.
"We've still got some people who are standing by until they see that water coming," Tidball said after a news conference at the state's Emergency Operations Center at the north edge of Pierre. "They want to stay and protect their homes as long as they can. And I can't blame them."
With massive Lake Oahe full and another surge of snow melt heading down the river system toward the reservoir from Montana and Wyoming, the U.S. Army Corps of Engineers continued to increase releases from Oahe Dam into what Oahe project manager Eric Stasch called "uncharted territory." That means more water is rushing down the river channel toward Pierre and Fort Pierre than at any time since the dam was completed in the early 1960s.
Other dams in the system are churning out similarly heavy flows, and flood issues are being faced up and down the river.
On Friday morning, the Corps increased the release from Oahe to 92,500 cubic feet per second (cfs), and by 4 p.m., it upped it to 100,000 cfs.
"Up until now, we've never gone over 60,000 cfs at Oahe," said Stasch, who has been at the dam since 1987. "And in a couple of hours, we'll be sitting at 100,000."
But they wouldn't be staying there for long. On Saturday, the two-stage increase will take flows to 120,000 cfs. And by Tuesday, they are scheduled to reach 150,000 cfs, including the water charging out from the main generating plant into the Oahe Dam tailrace as well as the roaring blast of water coming out of the rarely used secondary release outlets in the nearby stilling basin.
Stasch and other Corps officials believe that is as high as the releases will go, although that presumes no more of the monstrous rainstorms that swamped the upper Missouri Basin and washed out the projections of Corps officials that the Missouri River dams had enough remaining storage to handle inflows.
"That humongous rain that hit us, the statistics on that are mind-boggling," he said. "It took up that flood-control zone we had ready for this snow melt."
It also sent Brent and Linda Dykstra and many others like them in a race to protect their home on the west shore of the Missouri River in northern Fort Pierre. The Dykstras and their immediate neighbors live outside the residential areas to be protected by a hastily constructed earthen levee nearby. They thought they had their berm line high enough Thursday evening, but on Friday an engineer crew stopped to tell them they had to increase the height of the berm by two feet.
So they called for volunteers and began driving back and forth to the sandbag center at the fairgrounds in Fort Pierre. They also showed the effects of long hours of work and worry.
"We've been on our own from the beginning," Brent Dykstra said. "This is the fourth time we've raised this berm. It's really frustrating because we can't seem to get a straight answer on what it will take to protect ourselves. It keeps changing. This is the only line of defense for us."
Dykstra said he was frustrated by water level estimates by the Corps of Engineers that seemed to change and a lack of contact or guidance from the federal agency. But he was grateful for the volunteers and equipment that showed up to help.
"I hope we'll have this berm up another 2 feet by tomorrow night," Dykstra said late Friday afternoon. "Then, we wait to see what happens."
The waiting game has been less tense for many residents in the flood zone since construction began on the earthen levees that could make the interior sandbags and berms unnecessary in many areas, if the levees hold up against the heavy flows. Pierre Mayor Laurie Gill said the sight of the heavy machinery and work crews building up the levees was a comfort to people who had been on edge for days.
"Up until now, it's really been hunker down and get it done," Gill said. "But the day they could see progress on those levees, I think we all got a lot less tense."
Gill and other officials said they were confident the levees would hold. But they also were advising residents in the flooded areas to prepare for levee failures, to be safe. As water flows increase into that "uncharted territory," the projections of actual flows and their impacts of walls of earth are impossible to guarantee. The fact that the high flows are expected to last for weeks and probably months makes long-term projections even more difficult.
"I think it would be foolish to look at a situation of this scale, where it's never been experienced before, if you don't look at those numbers with some skepticism," Daugaard said. "But the numbers are the best we can get from those best able to judge them."