By Peter Chawaga, Associate Editor, Water Online
On the morning of August 29, 2005, Hurricane Katrina’s storm surge breached 53 flood protection structures in the greater New Orleans area and left 80 percent of it underwater. The storm buffeted the city with hurricane-force winds for hours, destroyed entire neighborhoods, and left residents scrambling for safety. The total property damage is estimated at $108 billion. The National Hurricane Center estimates the total resulting fatalities in Louisiana at 1,577.
Ten years later and it’s clear that some things will never be the same. While New Orleans has bounced back to recapture its inimitable place in the American landscape, the city has been forced to reinvent itself and rethink what it means to occupy one of the country’s most vulnerable locations to tropical storms.
There was plenty of blame to be spread in the wake of the devastation. A Congressional investigation indicted rescue efforts from the Federal Emergency Management Agency (FEMA) and Red Cross. Kanye West famously called President George W. Bush out on a perceived lack of sympathy for victims. A 2007 report by the American Society of Civil Engineers (ASCE), “What Went Wrong and Why,” found that two-thirds of the flooding was caused by failures in the city’s floodwalls and that many pump stations that could have removed floodwaters were inoperable during and after the storm. The findings raise questions about what the local government might have done to prevent such extensive damage with more preemptive investment.
“Serious deficiencies in the southeast Louisiana hurricane protection system must be corrected if the New Orleans area is to avoid a similar catastrophe when the next major hurricane strikes,” the report determined.
Readying The Perimeter
To address the levee issue, possibly the most visible failure when Katrina hit, the U.S. Army Corps of Engineers (USACE) completed a Hurricane and Storm Damage Risk Reduction System for southeastern Louisiana in 2011. The project included the repair of 33 pump stations, the storm-proofing of 34 pump stations, armoring of 420 “transition” spots where floodwalls meets levees, and the use of 93 million cubic yards of borrow, or levee clay. In all, the Greater New Orleans Perimeter System runs 133 miles plus 70 miles of interior defensive structures. As of May 2015, the total program budget reached approximately $14.6 billion.
Gerry Gillen, the executive director of the Orleans Levee District, is charged with operating and maintaining the flood protection perimeter around Orleans Parish Eastbank.
“The flood protection system as designed since Katrina is to prevent overtopping of a 100-year surge event,” he said. “Resiliency in the form of erosion protection has been added. This includes armoring where there is a transition from a concrete floodwall to an earthen levee, splash pads along the base of floodwalls, and a high-performance turf reinforcement mat incorporated into the protected side slope of the earthen levees.”
While these reinforcements offer crucial flooding protection for residents and property, the new system has its challenges and there is still room for improvement.
“The operation and maintenance of the improved levees, floodwalls, and surge barrier structures is challenging in that the system requires more manpower and equipment to meet the federal operation and maintenance requirements,” Gillen said. “Additional challenges are future levee lifts required due to settlement and to increase the levee elevation to protect for greater than 100-year storms.”
When The Water Seeps Through
There will always be stormwater that is capable of circumventing a wall and finding its way into the city. With that in mind, the city’s Department of Public Works (DPW) hopes to improve its stormwater management infrastructure.
“The city’s DPW is upgrading the drainage pipe system to manage a 10-year, 24-hour storm on the streets,” Cedric Grant, executive director of the Sewage and Water Board of New Orleans, said. “Today, street projects are reviewed to locate opportunities to add bioswales and green infrastructure bump-outs. The city has also expanded their allowable street details to include these and other green infrastructure features that retain, detain, and filter stormwater, thereby reducing peak flow pressure to the pump stations. DPW is also working to expand their accepted range of green infrastructure best management practices, including pervious concrete test studies in the Lower Ninth War and a pervious asphalt parking lot in City Park. In certain neighborhoods, the city is reestablishing historic drainage swales in test areas which manage stormwater at the street level.”
To prepare for the unwelcome but inevitable instance of interior flooding, several agencies have worked to shore up the capacity of the drainage system, said Grant.
The USACE has embarked on the Southeast Louisiana Urban Flood Control project to reduce damage due to rainfall in the Orleans, Jefferson, and St. Tammany Parishes. By 2017, the project aims to have built four new pump stations and revamp five others, plus improve drainage lines and canals, enlarge channels, replace bridges, detention ponds, and levees, and elevate certain structures.
Grant’s own Sewage and Water Board is also working to upgrade pump stations while DPW upgrades the capacity of the underground pipe system.
“The city’s newly enacted comprehensive zoning ordinance includes new stormwater management provisions for development projects that require parcels over an acre in size to include stormwater detention features,” Grant added. “It also encourages property owners to help with drainage by installing green infrastructure like utilizing a cistern or rain barrel, planting indigenous plants, and installing permeable paving.”
The Storm Ahead
Realistically, there is nothing New Orleans or any other city can do to completely protect itself from natural disaster. As the single costliest and one of the five deadliest hurricanes in the country’s history, a so-called 400-year storm for its unlikelihood of occurring, Katrina was a reminder of infrastructure needs, not the threat of a recurring event.
For New Orleans, notice of that reminder is evidenced in the investments outlined above. Coupled as Katrina tends to be with 2012’s Hurricane Sandy, American officials at large seem more aware of the storm potential posed by climate change and to consider stormwater management and infrastructure improvements as a priority. This year, the U.S. EPA launched a suite of climate adaptation tools to better prepare the nation for storm surges and President Obama issued an Executive Order to reduce the nation’s exposure to flood risk.
If we’ve learned anything in the 10 years since Hurricane Katrina, it’s that we need to be prepared for the next storm whether we see it coming or not.
Image credit: "Hurricane Katrina LA3," News Muse © 2005, used under an Attribution 2.0 Generic license: https://creativecommons.org/licenses/by/2.0/