(CNN) — As Hurricane Harvey takes aim at Texas, people in New Orleans are bracing for 10 inches of rain or more starting Sunday and continuing into early next week.
The daunting forecast comes just weeks after strong storms overwhelmed the city’s unique drainage system, leading to flooding at a couple hundred properties and exposing critical deficiencies among 100 large pumps that drain many neighborhoods.
Days later, a key turbine that helps generate an uncommon frequency of electricity needed to run the city’s oldest, most powerful pumps caught fire, leaving just one of five power turbines in working order.
While some repairs have been completed, “we remain in a state of diminished draining capacity until more of our turbines and pumps are fully restored,” Mayor Mitch Landrieu said Thursday. “We’re in a more vulnerable space than we should be in. … We’re getting a threat at a time when we’re not in our strongest position.”
Should New Orleans “get stuck in rain bands” if Harvey stalls over land, the projected rainfall could spike to as much as 20 inches over the early part of the week, Landrieu said, citing his latest briefing by the National Weather Service.
“This is what worries me the most,” he said.
High-water vehicles, boats and barricades were in place Thursday in case of dangerous flooding, Landrieu said. New Orleans remains under a state of emergency, which Louisiana Gov. John Bel Edwards declared in response to the flooding and the turbine failure in early August.
14 pumps still offline
Because of New Orleans’ unusual topography — with many areas below sea level and protected by levees — pumps in every neighborhood must suck rainwater through storm drains and canals and push it into a nearby lake or other water bodies. In most other cities, gravity does that work.
Pumps that drain rainwater from New Orleans’ streets are not the same pumps that the US Army Corps of Engineers built after Hurricane Katrina in 2005 as part of a $14 billion effort to fortify the city against tropical events. City-owned equipment did not figure into the deadly flooding during Katrina, which owed to the failure of federal levees, though some city pumps and other machinery were damaged in that flood.
Some city-owned equipment has been repaired or upgraded since Katrina — sometimes at federal expense — but local investment hasn’t kept pace with the system’s needs.
Fourteen drainage pumps still were out of service as of Thursday night, according to the most recent records posted online by the city-owned Sewerage & Water Board and a city spokeswoman. Of those, six pumps were relatively small and located in newer sections of the city where flooding weeks ago was not a problem. Another six were among the system’s 20 so-called “constant duty” pumps, which are also small and work to clear the streets of runoff from lawn watering and other daily water usage.
The two major pumps that remained out of service all were located at an enormous pump station in the city’s Lakeview neighborhood. Without those pumps, the capacity of that station, which serves a heavily populated swath along the city’s western edge and a large section of neighboring Jefferson Parish, remained reduced by about a quarter.
While the city’s drainage system remains impaired, Landrieu noted Thursday that even at its maximum design capacity, the pumps only can drain 1 inch of water in the first hour of a storm and a half-inch each subsequent hour. That means a deluge would predictably cause temporary localized flooding, an outcome most residents expect.
Heavy hitters take the reins
The turbine that broke August 9 has been brought back online, and officials said they have “mobilized 26 backup generators” in case of another power failure.
Much of the drainage capacity in the oldest part of New Orleans relies on power generated by the city. Some other pumps in that area — and nearly all pumps elsewhere in the city — run on power supplied by the local commercial provider, Entergy. But because overhead power lines tend to topple in high winds, city-generated and backup power sources are key to keeping drainage pumps running.
City crews also have cleaned more than 800 street-level catch basins since this month’s storms after residents complained that debris clogging the drains exacerbated flooding. The city is now poised to fast-track routine maintenance of its 68,000 catch basins.
And the mayor has installed a team of heavy hitters — including Paul Rainwater, who led the Louisiana Recovery Authority after Hurricanes Katrina and Rita in 2005 — to manage the city’s drainage infrastructure on an emergency basis.
Landrieu, who linked this month’s flooding to a scourge of aging and failing infrastructure across the country, swiftly moved to oust four key officials who he said hadn’t kept him abreast of the problems. They included the director and top engineer at the Sewerage & Water Board, which Landrieu serves as board president.