Receding floodwaters are exposing millions of dollars worth of damage to Wisconsin streets and highways, bridges and overwhelmed sewage treatment plants.

Engineers and administrators who have begun surveying the wreckage say it will be long months before everything is back in working order.

The mess translates into summerlong detours for drivers around collapsed roads and suspect bridges, basements sloshing with leakage from cracked sewer lines, and, in at least a few places, businesses shutting down because of stressed sewage treatment plants.

"I'm sure we'll be working all summer," said Baraboo city engineer Chuck Bongard.

Repair estimates continued to surface Tuesday. In Sauk County, where 60 percent of the highways are damaged, officials estimated the repair bill will be at least $2 million.

Early estimates of highway damage elsewhere included $250,000 to $300,000 in Crawford County for shoulder repairs and $150,000 to $200,000 in repairs in Richland County, where officials said they expect the final bill to be higher. Grant County estimated damage to state roads there to be about $100,000, with another $500,000 for county roads and $200,000 to $3000 for town roads.

In Juneau County, snowplows were used during the heaviest rains to clear mud off roads. Dennis Weiss, the county's commissioner of highways and public works, said repairing road washouts and removing downed trees from roads will probably cost $300,000 to $400,000 — about half of the county's entire $800,000 annual budget for road repairs.

Chris Klein, executive assistant at the state Department of Transportation, said that so far there is no comprehensive breakdown of the damage to state highways and bridges, and no timetable for repairs. Yet to be dealt with is the issue of whether construction projects planned for this summer will have to postponed because of repair work.

Streets and roads remain closed in many places because of collapses, either of the pavement or shoulders due to waterlogged soil and mudslides.

Crawford County Highway Commissioner Dennis Pelock said the effect of the flooding on transportation is frustrating.

"Every road down through the middle of the county was closed," said Pelock. "There was no way to go from the east side to the west side."

In Baraboo, where the Baraboo River through the middle of the city rose to a record flood level, city engineer Bongard said damage to streets is being revealed as floodwaters go down.

"The streets are our biggest priority," said Bongard. "Having roads out or damaged has the most impact on everybody."

Potentially damaged bridges are another problem in the wake of the flood, though the extent of the damage will not be known until more thorough inspections are carried out.

John Goetter, a private engineer in Milwaukee who's helped prepare reports on the state's infrastructure, said sometimes flooding can scour away the earth around certain types of bridge footings, threatening the stability of the bridge. Sometimes inspectors are able to use long poles to probe the footings and check them while waters are still fairly high.

But "you might have to wait until the water gets down to a normal level," he said.

Another concern is that air can get trapped beneath the decks of bridges and rising waters could actually lift the decks up, he said. To avoid that, state highway workers have been drilling holes in some bridge decks to allow the air to escape. Trees and other large debris might have struck bridges or their embankments and caused damage yet undiscovered.

Some of the flood's edgier moments for city engineers came when waters threatened to overwhelm sewage treatment plants. Now, according to Bongard, engineers are working to assess the damage to pipes and pumps. He thinks some of the problems encountered with broken sewer and water pipes had their beginnings as long ago as the massive flooding in 1993 when surging waters blasted grout and seals out of pipe joints.

That damage may have gone unnoticed and worsened the infiltration that forced many plants to divert raw sewage into streams and lakes, Bongard added.

Bongard said it is not difficult to understand how all the damage happened after witnessing the force exerted by the deluges that soaked southern Wisconsin and filled its rivers and lakes.

"There was one scene that will stick with me,'' Bongard said. "I remember a heavy steel manhole cover with an 8-inch-thick slab of concrete on top of it and the water just picked it up and floated it away. Several of us had to pick it up and put it back. It just absolutely amazes you."

State Journal reporters Gena Kittner, Heather LaRoi and Jason Stein contributed to this report.