Under water

'I'm just glad it's not raining,' Michael Marion said Tuesday as he surveyed the high tide water in front of his store, Stacey's Kitchen, on the corner of Reid and America streets.

Charleston isn't Atlanta, where more than a week of rain has flooded homes and highways and killed at least nine people. But the tri-county area is no stranger to flooding that can damage property and threaten lives.

A foot or two of rain in a week won't flood the Lowcountry disastrously, as it did in Atlanta. But that much rain in a day can, and has.

Charleston and surrounding towns and cities have taken steps to reduce drainage problems, ranging from the construction of costly pumping stations to the regular cleaning of drainage ditches; and more initiatives are planned.

Mount Pleasant, for example, is preparing a drainage repair project in the Olde Park subdivision that could cost up to $800,000, and Charleston is seeking a $143 million federal grant to construct a downtown drainage and pumping system that would cover about a third of the peninsula and, if approved, would become one of the largest stimulus projects in the state.

But there's only so much governments can do, and some low-lying areas defy easy solutions.

The fierce downpours typical of the coast threaten low-lying spots throughout the three counties. Who gets flooded out -- Otranto, Shadowmoss, St. Stephen, Oakbrook -- seems to vary randomly from storm to storm. It's a consequence of where the rain falls hardest and fastest, and sometimes how high the tide is, and where that area drains.

"It's not so much how many inches of rain fall, it's how fast it falls," said Mount Pleasant Administrator Mac Burdette. "It just overwhelms the system."

Unlike the hilly Atlanta area, where heavy rains flow downhill into swollen rivers that can jump their banks, Lowcountry floodwater tends to spread out, eventually draining into wetlands and waterways.

And because the region is flat, water doesn't drain anywhere in a hurry. In some areas, bowl-shaped depressions known as drainage basins can trap water across large areas, resulting in the need for pumping.

"The real disaster comes when flooding occurs in an area where it hasn't flooded before," said Dennis Clark, Dorchester County emergency preparedness director.

The horror stories are eerily similar. In 1999 in Summerville's Oakbrook community, nine inches of rain fell in three hours with the Ashley River at high tide. Runoff streamed from the drainage ditches. Water climbed five feet across streets and lawns in what seemed like moments. Cars were submerged. Fences were carried away. Nearly 100 homes flooded. A White Church resident watched the water slapping waist high outside her sliding door before pouring in.

In 2005, Hurricane Gaston appeared with little warning and dumped 11 inches of rain on Mount Pleasant in just 6 hours.

"Gaston was a mess," said Burdette. "That was probably the last time water got in somebody's house in Mount Pleasant."

Gaston stalled out over upper Berkeley County and dropped 14 inches of rain there. Families were flooded out of a dozen homes. Well water for Timberland High School was polluted by runoff.

That much rain in the upper county is considered a once-in-500-years event, said Frank Carson, Berkeley County engineer. "It's not something you can plan for. You plan for events that are likely to happen."

In downtown Charleston, flooding counts as an event that's likely to happen. High tides alone can block parts of Morrison Drive, and when some rain is thrown into the mix, it can be enough to flood the Crosstown Expressway and neighboring streets.

In October 2008, heavy rain at high tide put enough water on the ground to unexpectedly flood about 32 homes in the Bridge Pointe development in West Ashley. In downtown Charleston, the same storm left knee-high water across parts of East Side and West Side neighborhoods, where flooding is not uncommon but usually isn't that severe.

"The rain we had in October of last year, that was a huge event," said Laura Cabiness, director of the city's Public Service Department. "In our area, the low areas already flood; and when it rains, that just spreads it out more."

"Downtown, the solution we found is tunnels and pumps," she said. "When you want to get water out faster, you need a big conduit and a lot of force."

Charleston and Mount Pleasant both have pump stations and a need for several more. The city's are more elaborate, with deep tunnels and pumps capable of moving 130,000 gallons a minute.

Charleston has undertaken major drainage projects downtown and in several West Ashley neighborhoods. Next month the city will seek bids for a 12 feet-by-4-feet box culvert, essentially a square pipe, to reduce the flooding risk near Bridge Pointe.

Charleston City Councilman Larry Shirley, an insurance agent whose district includes Bridge Pointe, said the Atlanta flooding should be a good prompt for Lowcountry residents to examine their insurance and consider federal flood insurance if they don't already have it.

"What people in the Lowcountry need to know is we don't have to have a hurricane (to have flooding)," Shirley said. "The Atlanta issue should put everyone on alert."

Most of those who died in the Atlanta flooding drowned after their cars were swept off flooded roadways, the Associated Press reported.

In the Lowcountry, heavy rains at high tide can at least partially block major roadways in the area, including the Crosstown Expressway on the Charleston peninsula, U.S. Highway 17 near Awendaw, Longpoint Road in Mount Pleasant, Harbor View Road on James Island and Montague Avenue near Interstate 26 in North Charleston.

A deluge can cripple emergency response in Dorchester County, which simply doesn't have a lot of through roads to get around on, Clark said. That's an ongoing concern for emergency managers. All three counties continually update hazard mitigation plans that identify communities and structures that are most vulnerable to disasters like flooding, provide options for retrofitting or relocating them and recommend potential sources of funding, such as Federal Emergency Management Agency grants.

Other public agencies work on improving things such as transportation, land use and communications.

"Generally speaking, we're constantly becoming more resilient," said Alec Brebner, Berkeley Charleston and Dorchester Council of Governments planning director.

But the private sphere lags behind the public sphere in the effort. "A lot can be done. It's just a matter of cost," he said.