State Department of Natural Resources spokesman Greg Matthews said Tuesday that the swollen Wisconsin River is seeping through sections of the levee in the town of Caledonia, near Portage, but that the levee has held.
Floodwater from a nearby lake has also poured into the neighborhood.
The century-old earthen dike, part of a 14-mile berm, separates Blackhawk Park and the city of Portage from the Wisconsin River. But the water rose so high and so forcefully following days of heavy rain last week that it surged around the dike and poured into the bottom lands around the neighborhood, said Steve Miller, director of the DNS Bureau of Facilities and Lands.
The flooding enclosed Blackhawk Park and engulfed the only access road into the neighborhood in Caledonia just southeast of Portage.
Many homes along the Wisconsin River, including vacation cottages and cabins, are underwater, reports CBS Affiliate WISC.
While some of the homes in low-lying areas stand on high ground and are not affected, they are only accessible by boat.
"I feel really bad for them," resident Randy Lloyd told WISC. "Down the road there are so many homes that are just trashed. I mean, they are really bad."
On Sunday, emergency workers asked the approximately 300 people living in the neighborhood to evacuate their homes, warning that they could be cut off by the burgeoning river. Beghin said about 25 homes in Blackhawk Park remained occupied Monday.
Gov. Jim Doyle declared a state of emergency for Columbia County Monday after the Wisconsin River reached a record high level. The declaration directs state agencies to assist in recovery efforts.
Much of the levee protects forest and farmland, but a breach in the Blackhawk Park portion could wash away the access road altogether. Beghin said that under that worst-case scenario, remaining residents could be stranded for up to a week.
DNR workers were using sandbags to control the seepage, and Matthews said the effort seemed to be working.
Forrest Travis, a 53-year-old part-time construction worker, said he spent Sunday night at his fishing camp and didn't have any plans to go anywhere, even as water rushed across the gravel service road a few steps away.
"I'm not worried about it," Travis said. "It would have to get a lot higher to get where we're standing."
Diana O'Neill, 56, a retired De Forest police officer, evacuated Sunday. On Monday, she inched her truck along the access road, creating a wake, to get back to her house.
Her place was still dry when she arrived. She grabbed three dozen eggs and her Chicago Bears shirt for the Green Bay Packers-Chicago Bears game Monday night and inched her way back out. The water was easily an inch higher than when she drove in.
"I'm kind of a risk-taker," she said. "If it wasn't for the road being overrun I would have stayed here. I've got stuff to get done."
The Wisconsin River runs along the outskirts of Portage, a city of about 10,000 people some 40 miles north of Madison that touts itself as "Where the North Begins." The river had overflowed its banks by dozens of feet, pouring onto low-lying roads.
Residents ventured to the water's edge to watch as the river surged by.
Staring at the churning water, Shawn Schweitzer, 39, of Portage, said that usually at this time of the year the water is so low you can nearly drive across the river bottom.
"Now it would be bye, bye," he said as he watched the current swirl and eddy. "I've never seen it move this fast."
State and local officials were so concerned about the integrity of the 14-mile levee system homeowners built in the 1890s, a group was established to study it.
The group recommended in 2007 that because the levee was so unsafe and unable to protect against flooding, property owners should be offered incentives to move.
Miller said little has been done to make changes since the report came out.
National Weather Service hydrologist Bryan Hahn says the Wisconsin River reached a record level of 20.59 feet Monday at 6 a.m. That breaks a previous record of 20.50 set back in 1938.
The river was expected to hold steady through Tuesday, Hahn said, then slowly decline over the next seven days.
In South Dakota, Sioux River Water Levels Stable
In South Dakota, water levels in the storm-bloated Big Sioux River were stable Monday after up to 4 inches of rain last week pushed the waterway over its banks along a 50-mile stretch from Brookings to Sioux Falls.
"Over the years as we've had more floods, the people of Renner are slowly getting their basements filled in and just having a crawl space and moving all electrical and furnaces up above," Schmitz said.
(Left: Water that overflowed from the Big Sioux River sits in the town of Renner, S.D., Sunday, Sept. 26, 2010.)
The Big Sioux between Dell Rapids and Baltic on Monday experienced a secondary crest of 15.5 feet, which a little less than a foot lower than Saturday's peak, said Mike Gillispie, a hydrologist with the National Weather Service.
"The Renner area is probably the worst right now, and the only one I know of that has actually had any impact in the town," Gillispie said.
Downstream near 60th Street in Sioux Falls, where flooding would be limited to greenways and city parks, the Big Sioux was expected to crest at 15.5 feet overnight. That's just a couple of inches higher than Monday morning's level.
Gillispie said the whole area across Minnehaha County should see water levels that are fairly flat for the next 12 to 24 hours.
"Anything that hasn't started dropping now will start dropping by this time tomorrow," he said.
Teams Assess Flood Damage in Minnesota
Minnesota Gov. Tim Pawlenty reached an agreement with legislators on a special one-day session next month to approve relief money for people affected by floods after heavy rain last week caused serious flooding in that state.
Teams from the Federal Emergency Management Agency and the state's emergency management division continued to assess flood damage in southern Minnesota Tuesday.
Minnesota Department of Public Safety spokesman Doug Neville says four teams from FEMA and the state Division of Homeland Security Emergency Management planned to visit individual homeowners in eight counties Tuesday, including Martin, Blue Earth, Steele, Rice, Faribault, Waseca, Wabasha and Dodge counties.
Neville says teams are looking for uninsured losses, concentration of damages and the impact on communities. He says they hope to have a preliminary total on individual damage by the end of week.