COLUMBIA, S.C. (AP) — Long before the historic floods of the past week, crumbling roads, bridges and dams and aging drinking water systems plagued South Carolina — a poor state that didn't spend much on them in the first place and has been loath to raise taxes for upkeep.

Now the state faces hundreds of millions if not billions of dollars' worth of additional bills to fix or replace key pieces of its devastated infrastructure.

As the aftermath of Hurricane Sandy and other disasters shows, the federal government will cover much of the costs, but isn't going to pay for all of it.

"You're not going to have people down there tomorrow giving out money," said Gerry Galloway, a civil engineering professor at the University of Maryland.

It will take weeks or months to document the full extent of the damage, and to find out how much federal aid is coming South Carolina's way. That aid likely will come with requirements that bridges and dams be built to stronger, more expensive standards.

So the Republican-controlled state's leaders — who recently shot down a business-backed effort to get an extra $400 million a year for roads by raising some taxes and lowering others — likely will have to grit their teeth and come up with matching funds.

In the meantime, barricades will be blocking commutes for a long while.

A former trucker, Jerod Anderson currently drives a car to take pictures used in street mapping software, so he knows his way around. But just getting to and from his house in the swampy area of Richland County, he's found road after road barricaded and driven miles on alternate routes only to find the next bridge closed.

He nearly reached the breaking point Tuesday when he drove into Columbia on a route several miles longer than usual, then found out it was closed when he tried to go back that way several hours later.

"I've accepted that it is just going to be difficult," Anderson said. "But I'm not happy about it."

Workers have fanned out across the state looking at bridges, but right now it is mostly just informal inspections to see if it is obvious that a bridge or road should be shut down.

South Carolina Department of Transportation worker Radames Zambrana was at a bridge Wednesday where flood waters washed out the support underneath. He was getting ready to request big barricades be put up instead of the small traffic cones to make sure no one drove on the intact pavement, supported by almost nothing.

"I'm seeing this everywhere," Zambrana said, pointing at the gaping hole under the bridge where soil was washed away.

About 260 roads and 150 bridges remained closed Wednesday, many of them washed out, according to the Transportation Department.

South Carolina depends almost entirely on its gas tax to fund highway maintenance, and it hasn't raised its gas tax since 1987. Even before the floods, 20 percent of the state's 8,300 bridges were rated structurally deficient or structurally obsolete, and a road advocacy group made up of business leaders estimated it would take $500 million extra a year just to patch the pothole-dotted roads that shake vehicles as they drive over them.

The state periodically closed deteriorated bridges until they could be repaired, and even heading down interstates and major highways could rattle cars so violently they need frequent alignments. Over the past several years, the state has paid tens of millions of dollars to settle claims over vehicles damaged by potholes or poorly maintained roads.

South Carolina's poor spending may have made the problems from the flood even worse, the rushing water a final blow against crumbling structures, said Galloway, the Maryland professor.

State officials reported at least 11 small dams have failed in a state where some 200 dams are considered high-hazard, meaning they could significantly threaten life and property if breached. The state spends less than $200,000 a year on dam safety.

Drinking water supplies, too, have gone wanting. Some customers have sued the state's capital and largest city, Columbia, for diverting water system profits to pay for economic development projects even though the Environmental Protection Agency had ordered $700 million in fixes to the aging system.

Now the city is using giant sandbags dropped by National Guard helicopters to try to plug a canal breach that threatens its entire water supply. It's also scrambling to repair a slew of water main breaks that left tens of thousands of customers with empty taps.

Gov. Nikki Haley made South Carolina a promise Tuesday: "We're not going to stop until we get everything back up and fixed again," she said.

But she wouldn't get into where the money will come from.

If Congress decides to consider a special relief bill, South Carolina could face a different kind of payback. Five of the state's six U.S. House members and both U.S. senators voted against an aid package for northeastern states after Hurricane Sandy in 2012.

Another storm that waylaid the Northeast the year before might give a hint to South Carolina's future. Widespread flooding from Tropical Storm Irene in August 2011 severely damaged infrastructure in 225 of Vermont's 251 towns, wrecking more than 300 bridges, 500 miles of state highways and 2,200 segments of town roads.

The Federal Emergency Management Agency has directed more than $210 million to Vermont for public assistance that includes infrastructure repairs. The Federal Highway Administration has provided about $150 million in additional aid, according to Vermont officials.

To get federal dollars, states often must chip in some of their own money. Vermont, which had been building up a funding shortfall even before Irene, raised its gas tax by about 6 cents a gallon in 2013 as it was in danger failing to meet its required match for federal highway funding.

Ultimately, the storm improved Vermont's infrastructure by forcing the replacement of some bridges that had stood for 80 years and several that had been rated as structurally deficient.

Some of Louisiana's roads also have been rebuilt bigger and better after Hurricane Katrina devastated the state in 2005. The twin 5.4-mile bridges that carry Interstate 10 over Lake Pontchartrain originally had been built in 1965 with two lanes in each direction. The new $769 million, federally funded bridges have three lanes carrying traffic into and out of New Orleans.

"It's wider, it's taller, it's stronger," said Rodney Mallett, a spokesman for the Louisiana Department of Transportation and Development. "This bridge would be able to withstand something the likes of Katrina."

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Lieb reported from Jefferson City, Missouri. Associated Press reporter Wilson Ring in Montpelier, Vermont, contributed to this report.

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Follow Jeffrey Collins on Twitter at http://twitter.com/JSCollinsAP and David A. Lieb at http://twitter.com/DavidALieb .