Preserving the Environment

New Orleans Floods With Heavy Rainstorms. Magnolias Could Be Part of the Solution

August 17, 2018
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New Orleans Floods With Heavy Rainstorms. Magnolias Could Be Part of the Solution
A boy paddles his canoe through flood waters on September 4, 2011 in Lafitte, Louisiana, after Tropical Storm Lee hit the state. Photo by Sean Gardner/Getty Images
This program is paying city residents to ditch concrete in favor of flowers.

Louisiana weather in the summer is temperamental — and residents brace for the worst every year.

People who live in this swampy coastal state know that a light rain could easily turn into a torrential downpour, resulting in sheets of water that spill from rooftops and flood the streets or overflow estuaries that feed into larger lakes.

That’s exactly what happened in New Orleans earlier this summer, and last summer and the summer before last.

“If there’s a half inch of rain falling, my street is flooded,” says Ramiro Diaz, an urban architect who sits on the board of the city’s Zoning and Adjustments Commission. “It’s an intensity thing. For us, a regular rain here is like monsoon rains for people in California. We can get half an inch of rain in 15 minutes.”

The problem isn’t just that New Orleans is a wet city that sits on top of water tables, or that it’s surrounded by swampland and is also partly below sea level (and sinking even more). It also has a lot to do with the way the city looks: It’s completely gray.

Pavement in New Orleans is everywhere, especially in the suburbs. Those areas — some of the lowest-lying in the city — are where water is meant to drain from the higher elevation areas, such as the French Quarter. But the excess of pavement covering such neighborhoods has transformed permeable land into impenetrable surface. As a result, water that should flow to the suburbs at a pace slow enough for the city’s drains and pumps to manage it is moving too quickly. And there’s just too much of it.

But a city-backed initiative is helping city residents manage flooding on their properties. The project, Front Yard Initiative, reimburses homeowners to tear out pavement in their yards and replace it with rain gardens, local plants that can absorb large amounts of water and rain barrels. So far, the Front Yard Initiative has been adopted by 43 homeowners in three New Orleans neighborhoods, and city planners have argued that the project — if adopted by enough people — might help reduce flooding throughout the city.

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An aerial view of the French Quarter of New Orleans shows just how gray the city can appear.Photo by Jonathan Densford/iStock/Getty Images

A GRAY CITY

Vivek Shaw lives just off Broad Street, a main thoroughfare in the Mid-City neighborhood, north of the French Quarter. His street is standard-issue New Orleans suburb: shotgun homes and Creole cottages, many raised on stilts, lined up side-by-side. All of the landscape is paved.

“All this [pavement] contributes to flooding,” Shaw says, pointing to one home on his street that is paved all the way around its perimeter. Next to Shaw’s home, crates have been placed for residents to cross the sidewalk to their stoops when the street floods. In August of last year, Shaw’s street, St. Ann, had 22 inches of flooding due to a heavy rain.

St. Ann is designed like most of the streets in New Orleans: The road has a slight downward tilt so that rainwater can run to the catch basins on Broad Street. The slope is slight enough so that instead of rushing down, the water moves in a measured way to the main thoroughfare, where the city’s five massive turbines and 120 water pumps push water back out to Lake Pontchartrain and, eventually, the sea.

But concrete has made that process cumbersome. Plants, sod and general greenery could easily absorb thousands of gallons of water so that the pumps aren’t overwhelmed, but most of the natural flora is gone.

“It’s like trying to drain a bathtub into a pipe the size of a straw,” says Diaz. “The more we pave the city, the faster the water runs off to those drains. And the drains are undersized and overwhelmed with rainstorms.”

(It’s also worth noting that the city found the drain pipes clogged with, literally, tons of Mardi Gras beads.)

It’s unknown how much pavement actually covers New Orleans. The city has never had a GIS — a software approach to mapping geographic and architectural layers of a city — officially in place. Heavy construction of the city after WWII meant that the suburbs were booming in Orleans Parish, but that also meant draining away the water shelf and paving over the land.

Paving land in this part of the South was deliberate, in order to fend off disease — stagnant water and natural ditches in the ground are breeding grounds for mosquitos, says Diaz.

“Ditches were vectors for disease. Once we realized, for example, yellow fever was water-related, we got rid of the water everywhere,” says Diaz, whose architecture firm was key in creating an urban water plan proposal. “To get rid of mosquitos you have to annihilate everything.”

New Orleans is built on a foundation of wet clay. By paving over it indiscriminately, the clay is drying out and shrinking, a process called subsidence that leads to infrastructure nightmares like cracked roads and shattered pipes.

As a result, the city is falling ever deeper below sea level — and that’s making the situation even worse. A city that once did its best to keep the swamp away is now swimming in water.

TEAR IT UP

Walk through any garden party in New Orleans and you’re bound to encounter a whiff of honey and spice. It’s the telltale smell of swamp milkweed, pink bushels of flowers native to the South.

Swamp milkweed is one of dozens of plants in the area, including sweetbay magnolias and dwarf palmettos, that can absorb large amounts of water. They’re just a few of the plants that Front Yard Initiative recommends using when decorating water-absorbing lawns, says Felice Lavergne, a project manager for the Urban Conservancy.

“These plants practically live in water,” says Lavergne. “They have deep roots that take in the ground water which helps with absorption.”

Front Yard Initiative’s reimbursement levels for pavement removal are small, Lavergne admits, only $2.50 a square foot, up to a max of $1,250 per property. The cost of removing pavement is often three times that high — which doesn’t factor in landscape and gardening costs — but it’s an incentive for homeowners to take action in communities that suffer consistent flooding. (The program has reimbursed homeowners a total of $42,446 to date.)

So far, Front Yard has been able to clear over 25,000 square feet of pavement. That’s only half the square footage of a typical football field, but breaking it down by household, an average of 600 square feet of pavement has been removed from 43 homes.

One Broadmoor homeowner tore up 343 square feet of pavement around his home and replaced it with bioswales, gravel and underground water storage that holds 11,000 gallons of water — enough water to fill a small swimming pool. The home takes in water for the whole street.

And that makes a difference, says Lavergne.

“We can’t say that replacing pavement with a rain garden is going to stop flooding, but it absolutely alleviates it,” she says, adding that Front Yard Initiative’s collective yard-greening so far captures over 35,000 gallons of water.

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Vivek Shaw stands in front of his home and rain garden in Mid-City, New Orleans. His neighborhood last year had over 22 inches of flooding, which, officials say, can be alleviated in the future if more neighborhoods replace pavement with greenery.Photo by Joseph Darius Jaafari

It’s exactly what Shaw, the homeowner on St. Ann Street, did when he first moved in. He removed less than 100-square feet of concrete from his front yard and replaced it with a rain garden that holds 80 gallons of water.

“It’s small, but if everyone does it, we might not have as much flooding,” he says.

That’s not untrue, says Diaz. He and his team found that if everyone in New Orleans Parish had some form of water storage — even 30 gallons worth, or enough to fill a rain barrel — pumps wouldn’t be inundated with rainwater during heavy rains.

The Front Yard Initiative has received verbal support from the city, which has been under increasing pressure to build a more resilient New Orleans after Hurricane Katrina. After 12 years, the storm still wreaks havoc on city budgets that are geared towards rebuilding streets via FEMA grants that only permit streets to be rebuilt exactly as they were before the 2005 storm.

“We got all this money from FEMA to fix our streets, but if you [fix] a street back to what it was when it didn’t work, it doesn’t make much sense,” Diaz says.

City officials have struggled for years to find money for projects to revitalize roads and allow water to flow down them in more sustainable ways, and city councillors have turned to federal grants to fund more resilient landscape programs that resemble the Front Yard Initiative’s program.

In the Gentilly neighborhood, for example, $141 million in Housing and Urban Development grants will fund the creation of a massive rain garden which could hold up 1.23 million feet of water.

And Urban Conservancy, Front Yard Initiative’s parent organization, has partnered with Greenlight NOLA to incentivize homeowners to replace their pavement in conjunction with the resiliency project.

“This is a community effort,” says Lavergne. “In New Orleans, you know your neighbors, you care for your neighbors and hang out with them and know each other’s kids. By protecting your home in this really simple way, you’re protecting your neighbor.”

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