As world talks climate, US city fights flooding, sea rise

AP News
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Posted: Dec 08, 2015 3:23 PM
As world talks climate, US city fights flooding, sea rise

CHARLESTON, S.C. (AP) — About 175 years ago, a Charleston mayor offered a $100 gold medal to anyone who could stop the floods in the small coastal city.

That medal was never awarded, the flooding was never solved, and now it's much worse. Because of urban development and rising sea levels, the slow-moving catastrophe of climate change has near-daily consequences in the historic city.

"Charleston is essentially ground zero for some of the more severe changes we can anticipate," said Hamilton Davis, the energy and climate director for the South Carolina Coastal Conservation League.

In response, the city is engineering a fix with tunnels and pump stations that costs about $250 million — more than one-and-a-half times its annual budget. It's a commitment few other communities on America's East Coast have made.

Mayor Joseph P. Riley Jr., a Democrat winding up 40 years as the city's chief executive in the Republican-led state, said the $80 million in drainage work already completed prevented even more extensive flooding in October, when a so-called 1,000-year-storm dumped 16 inches of rain, shuttering Charleston and much of South Carolina for three days.

"The damage would have been far more severe," Riley said. "I think it's proof that these very costly and major construction projects are extremely helpful."

Charleston occupies the end of a peninsula between the Ashley and Cooper Rivers - two estuaries that, as locals like to say, meet to form the Atlantic Ocean. The city founded in 1670 has expanded ever since, filling in creeks and marshes that once drained water.

Rainstorms rendered many streets unpassable at least six times this year. Even on sunny days, high tides can flood low-lying areas — it happens about 23 days a year now, roughly four times as often as it did 50 years ago. On stormy days, runoff cascades through the narrow streets, forcing locals and tourists to wade through deep pools. Savvy residents sometimes use kayaks or rubber boats to get around.

"When you are late for work or you can't drop your kids off at school because there is flooding, you are more motivated to solve that problem," Davis said. "It makes it more real for people."

Some climate-change projections forecast waters rising by two feet and inundating 40 square blocks in Charleston by 2070.

"There are three basic approaches to sea level rise," said Erika Spanger-Siegfried, a senior analyst for the Climate & Energy Program of the Union of Concerned Scientists. "You can defend against the water with walls to keep it out. You accommodate the water by living with it and elevating buildings and creating channels. Or you retreat."

Charleston, where the first shots of the Civil War were fired at Fort Sumter, is not known for retreating.

Following a master plan engineers drew up in the 1980s, $80 million of the work is already completed. Deep shafts have been sunk into the grayish marl — a crumbly sediment of silt, clay and the remnants of sea shells that buildings rest on. Huge equipment is boring miles of horizontal tunnels up to 12 feet in diameter, connecting pump stations that send floodwater into the rivers.

The drainage system runs deep to avoid other underground infrastructure, including water and sewer tunnels built during the city's almost 350-year history. Work continues 150 feet below the city's historic homes and churches, trendy restaurants, the former slave market and other attractions that draw millions of visitors a year. This year, work also began along U.S. Highway 17, the main coastal route, which also routinely floods.

Riley said the cost of the work completed, under way and planned adds up to about $250 million, in a city with an operating budget of about $150 million. Property taxes and stormwater fees pay for the city's estimated $145 million share; the rest is federal and state money.

"That's a substantial capital investment for a city our size," Riley said, and cautioned that even more drainage work and perhaps walls to protect waterfront streets may be needed as water levels rise. "As each year's worth of data comes in, it gives you better guidance on what long-range sea level rise is and it's prudent to plan for intermediate steps," he said.

New York City, with an annual budget of $79 billion, has embarked on a $20 billion program to provide shore protection since Superstorm Sandy. Miami Beach, Florida, with a budget of about $300 million, has is building seawalls, raising roads and installing pumps at an estimate cost of $500 million.

Norfolk, Virginia, which annually spends $7 million on storm and sea-level rise mitigation, plans to pursue projects totaling more than $1 billion, which is roughly equal to its annual budget.

Back in 1837, Charleston Mayor R.Y. Hayne warned citizens in his annual report that a better drainage system "is essential to enable Charleston to fulfill her higher destinies." The city never awarded the proffered medal — worth about $2,500 in today's money — due to an economic panic that year, and the city has flooded, with increasing frequency, ever since.