Draining New Orleans taints lake

Floodwater being pumped from city is contaminated with bacteria, chemicals

Katrina's Wake

September 07, 2005|By Tom Pelton | Tom Pelton,SUN STAFF

Lake Pontchartrain, the brackish estuary that flooded New Orleans during Hurricane Katrina, is likely to suffer environmental damage as water fouled by sewage, bacteria and corpses is pumped from city's streets back into the estuary, officials said yesterday.

"There is no question that this water is contaminated, and it will have an impact on the lake," said Jean Kelly, spokeswoman for the Louisiana Department of Environmental Quality. "We've got dead bodies, cars, human waste, household hazardous chemicals, all kinds of pollutants in that water."

The lake is likely to rebound in time, authorities said, but in the short term it will be far more polluted.

No treatment

The government had no choice but to pump the brew directly back into the lake without treatment because none of the 400-plus sewage treatment plants in the flood zone is working, Kelly said. Saving what remains of the city is a higher priority than a setback in the lake's water quality, she said.

Rumors have been circulating of a "toxic soup" washing through New Orleans. To get a scientific measure of what pollutants are in the floodwaters, the state and the U.S. Environmental Protection Agency have taken samples and sent them to labs in Baton Rouge and Houston for analysis.

Meanwhile, the EPA is warning survivors and rescue workers to limit their contact with the water, especially if they have cuts that could become infected by the raw sewage, according to a news release sent out by the federal agency.

Holes plugged

The Army Corps of Engineers succeeded Monday in using giant sandbags, dropped from helicopters, to plug the holes in two levees that caused the flooding, said Al Naomi, senior project manager for the corps.

Working with the New Orleans Sewage and Water Board, the corps re-started four of the city's two-dozen pumping stations, which are now shooting the floodwater over the barriers back into the lake, Naomi said. Water levels in city streets are dropping, but it might take up to 80 days to complete the pumping, he said.

The task is Herculean, in part because most of the city is below sea level, Naomi said. As the storm surge rolled in from the Gulf of Mexico to swell Lake Pontchartrain, the bay rose to more than nine feet above sea level, overwhelming the levies.

Lake Pontchartrain is a shallow tidal estuary immediately north of New Orleans, similar to the Chesapeake Bay but much smaller, only 630 square miles, compared with the Chesapeake's 3,380 square miles.

It was formed about 5,000 years ago by the Mississippi River as it meandered through swamps into the Gulf of Mexico.

The Choctaw Indian tribe called the estuary "Okwa-ta," which means "wide water." But French explorer Pierre LeMoyne Sieur d'Iberville renamed the lake in 1699 after one of his bosses, a French government minister in charge of marine expeditions, Louis Pontchartrain.

Like the Chesapeake Bay, Lake Pontchartrain is a vital nursery for fish and crabs, and it is beloved by New Orleans area residents as a place for sailing, swimming and fishing, said John Day, an ecologist at Louisiana State University.

"It's every bit as important as the Chesapeake Bay or the Everglades or even Yellowstone National Park," Day said.

Water quality in the lake began to suffer seriously in the 1930s and 1940s, as the oil industry began to dig wells around the lake, dredging canals, spilling oil and destroying wetlands, according to the U.S. Geological Survey.

Companies damaged the ecosystem by raking the bottom of the lake for oyster shells, which were used as building materials in the construction of roads.

Storm protection

Because of repeated overflow from the lake into New Orleans during storms, in the 1950s the government built a series of hurricane protection levees along the south shore of Lake Pontchartrain.

After every storm, the city has pump polluted rainwater out of its streets into the lake, said Donald F. Boesch, president of the University of Maryland Center for Environmental Science and a native of New Orleans who advises the federal government on managing the lake.

During the 1970s, sewage leaks from New Orleans forced many swimming areas along the lake to close. But the lake has seen its water quality improve over the past decade, as activists mobilized a "Save Our Lake" campaign like the "Save the Bay" battle for the Chesapeake, Boesch said.

"The lake has been getting better, looking at water clarity and the return of submerged aquatic vegetation," he said.

Boesch predicted the lake will rebound. But he said the storm is likely to deal a temporary setback by washing in everything from diesel fuel to human waste. Algae are likely to bloom and spread on the lake and then die, sparking the growth of bacteria and the consumption of oxygen, killing marine life, Boesch said.

Another problem is that the lake normally is mostly fresh water, with a little salt. The hurricane drove huge amounts of salt water in from the Gulf of Mexico, and this increase in salinity might hurt cypress swamps on the west side of the lake that cannot tolerate high salinity, Boesch said.

"The big storm surge mobilizes all of the debris of society that sits on the ground in the city," he said. "The thing to be concerned about most is human health. ... I would be concerned about diseases and pathogens in the water."

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