CHICAGO (Reuters) – Levees hastily erected along the Missouri River in central South Dakota were holding on Sunday as flooding caused by heavy spring rains and a melting winter snowpack continued to raise the waters toward record levels, officials said.
But the pressure on the earthen berms in Pierre and Fort Pierre, and the anxiety of area residents, will continue to increase through Tuesday, when the water being released at a dam just above the two towns reaches its peak of 150,000 cubic feet (4,247.5 cubic meters) per second -- nearly double the 85,000 cubic feet per second being released last week.
Officials have not yet ordered mandatory evacuations in the state. But as many as 3,000 Pierre and Fort Pierre residents, and more than 800 of the 1,100 homes over 250 miles away in Dakota Dunes, are threatened.
So far, the releases from the Oahe Dam have raised water levels along the Missouri in the state more than a foot.
"All the levees are holding at this hour," said Nathan Sanderson, spokesman for the Southeast Incident Management Team, which is warily watching the creeping floodwaters in Dakota Dunes in the extreme southeastern part of the state.
Sanderson said the evacuations there continued to be voluntary but added that officials were "encouraging people to leave."
Police have tried to reassure wary residents that their homes will be watched and access to their neighborhoods controlled.
"We know citizens are extremely worried during this time," said Union County Sheriff Dan Limoge.
"We hope to ease some of their concerns by assuring them that their homes will be vigilantly watched around the clock until this situation has passed."
RECORD SNOW, RAIN
Record snowfall at the Missouri's headwaters this winter and record rainfall this spring have swollen the Mississippi tributary and pushed the dams and reservoirs along it that are designed to control the usual seasonal surge this time of year to their limit.
So to protect them, the U.S. Army Corps of Engineers has been slowly opening up the dams and reservoirs upstream, gradually lifting river water levels downstream from North Dakota and South Dakota,
The U.S. Coast Guard has closed a more than 180-mile (290-kilometer) stretch of the river from near Sioux City, Iowa, south due to high water.
Farther downstream, the river is beginning to swell beyond its banks in Nebraska, Iowa and Missouri and officials braced for evacuations and built levees. The maximum planned release rates could push the river up to seven feet above flood stage at Sioux City, Omaha and Kansas City.
The result is a creeping problem expected to continue into July, adding to an already record season of flooding in the Midwest, where the rising waters of the Mississippi River caused forced evacuations and intentional inundation of thousands of acres in April and May.
The Missouri is expected to continue to rise rapidly in Pierre until Tuesday, when controlled releases from the Oahe reach maximum levels -- where they may hold for weeks.
In Montana, the Corps has increased water flows from Fort Peck Dam and widespread flooding of tributaries has forced hundreds of evacuations and inundated several smaller cities.
The Missouri River basin forms the northwest section of the Mississippi River system that stretches from the Rockies to western New York in the north and funnels water down through Louisiana to the Gulf of Mexico.
(Additional reporting by David Bailey in Minneapolis; Editing by Jerry Norton)
