NORTH SIOUX CITY, S.D. (AP) – A swollen river that threatened homes where Iowa, Nebraska and South Dakota meet crested earlier and at a lower level than expected early Friday.
The less-serious crest prompted crews to start taking down sandbags and other containers blocking a section of Interstate 29 that acted as a temporary levee to protect an at-risk South Dakota city.
The National Weather Service had predicted that the Big Sioux River would hit a record high around midday. But the service said Friday morning that the river crested at Sioux City, Iowa, around midnight a couple of feet below the previous record.
Days of thunderstorms upstream swelled the 420-mile-long river and threatened homes and businesses in the three surrounding states, including up to 400 in the McCook Lake neighborhood of North Sioux City, South Dakota.
Crews built a temporary levee across a section of Interstate 29 to protect the city, forcing motorists to make detours along country roads. Around midmorning Friday, National Guard soldiers and South Dakota Transportation workers started dismantling the levee. An Associated Press reporter on the scene said crews were removing the sandbags and other containers that had been blocking the freeway.
The governor’s office said I-29, which has been blocked since around noon Thursday, should reopen later Friday.
Floodwaters blocked many of the roads connecting South Dakota and Iowa between Sioux Falls and Sioux City.
“Great news,” Gary Bogenrief, 65, who lives on the south side of McCook Lake, said upon hearing the levee was coming down.
The change in the crest was due to a large amount of water released Tuesday night when a levee failed about 27 miles upstream at Akron, Iowa, said Mike Gillispie, a hydrologist at the National Weather Service in Sioux Falls.
“What we had based our forecast on here at North Sioux City was on major water flow that we had at the Akron gauge,” he said. “Enough water went through the levee failure out into agricultural land there that it lowered the amount of water coming through at peak crest at Sioux City.”
The river had been expected to crest at Sioux City about a foot above the 108.3-foot record set in 1969. Instead, it peaked at 105.6 feet and began dropping.
As a result, the river in the Sioux City area will stay at a higher level longer than previously predicted, Gillispie said. He expects the river to stay above the 99-foot flood stage, the level at which farmland around Sioux City is underwater, into Sunday afternoon or Monday morning.
He said as long as the area doesn’t get heavy rain over the next few days, the water should fall back below flood levels. While there is potential for scattered thunderstorms, he doesn’t anticipate the widespread heavy rain that could send the river significantly higher.
Downstream, Omaha Public Power District said it will reduce power as it prepares for rising water on the Missouri River. The district’s Fort Calhoun nuclear power plant sits about 20 miles north of Omaha, and was surrounded by water during the flooding three years ago.
Pitt reported from Des Moines, Iowa.