More trees mean less flooding, urban forestry advocate says
Susannah Burley was dealing with an insurance adjuster when I caught up with her to talk about green infrastructure in the aftermath of the most recent unexpected New Orleans flood.
“I live in the Fairgrounds Triangle neighborhood, and we got water inside of our rental property and both cars,” she lamented. “My husband’s car will be OK, but the adjuster wants to total mine.”
I met Burley a couple of years ago when she led the education program at Parkway Partners and I took the “Green Keepers” classes. Burley became so committed to the idea of using rain gardens, retention ponds and appropriate street plantings to reduce flooding that she left Parkway Partners and founded a new nonprofit, SOUL NOLA, in June 2016.
“It’s an acronym for Sustaining Our Urban Landscape, and the idea is to work neighborhood by neighborhood to help residents form a strategic plan to reduce dramatically the amount of stormwater that goes into catch basins and the drainage system,” said Burley, who also holds a master’s degree in landscape architecture from LSU.
“We had a lesson last weekend in the limits of what drainage systems can do … and we know it won’t stop flooding in the future. We need green infrastructure.”
The catastrophic flooding of last weekend appears to be the result of problems with the pumps and an abnormally large volume of rain in a short period of time. Yet Burley said that a robust approach to creating “green infrastructure” citywide might have reduced the flooding by keeping rain water out of the streets.
If the terms “green” and “infrastructure” don’t seem like they belong together, Burley says it’s because the idea is new to most cities.
Before Hurricane Katrina, the goal was to ensure that rainwater reached the drainage system as quickly as possible so it could be pumped to Lake Pontchartrain. Thinking has changed.
Now the idea is to deal with rainwater where it falls and to find ways to retain it or slow its path to the drainage system so the system won’t be overwhelmed and so rain can seep into the ground and replenish groundwater, important to reducing subsidence. Rain barrels, rain gardens and the like are some obvious ways to do it.
“At City Hall Tuesday, we learned what it would take to completely rebuild the drainage system to handle more water — it’s not going to happen,” Burley said, referring to the public meeting held to discuss the flood.
“So green infrastructure has to become part of the city’s plan for the future. As long as we pin our hopes on the drainage system and ignore the benefits of using green infrastructure to handle stormwater, we’re going to flood over and over again.”
SOUL is working with neighborhood leaders in Mid-City and Algiers and is in the planning phases with Broadmoor on a project aimed at reforesting the city, one neighborhood at a time.
Burley says trees are critical to helping manage storm water because they drink it up, thereby keeping it out of the vulnerable storm water drainage system. The bigger the tree, the greater the water storage capacity, she said.
Some of the thirstiest include Sweetbay magnolia, pond and bald cypress, and red maples.
A map on SOUL’s website shows the locations of trees planted to date. Every time volunteers and neighbors sink another one into the ground, its location is plotted on the map.
Click on a tree icon and see the address of the property where the tree was installed, the tree type and the container size. SOUL monitors tree health and condition after planting, but it is up to the residents and neighbors to keep the tree sufficiently watered the first year.
Live oaks, sweet bay and Little Gem magnolias, Drummond red maples, native fringe trees and Savannah hollies are a few of the tree types that appear on the map. Larger trees (live oaks) have been planted on neutral grounds and smaller trees (small magnolias, for example) on residential properties at the owner’s request.
Burley said, “We need to stop thinking of trees and greenery as merely ornamental and think of them for what they are — our front-line defense against flooding.”
Yesterday I served food to a woman who hadn’t eaten in nine days, and to another woman shaking from hypoglycemia. I was volunteering in Walker, Louisiana at a church, a temporary site where people can sign up for DSNAP benefits. These people are the working poor and most have lost their homes and jobs to the unprecedented flooding of Louisiana over the last two weeks. Seeing these people in person rather than on the news was a powerful experience, and it reminded me of why I’m doing this, why I’ve gone out on a limb, with a husband, a 3-year-old, and a house note, to start Sustaining Our Urban Landscape, SOUL, yet another NGO in New Orleans.
We have been hit hard for the second time in 12 years. And we’ll get hit again, likely soon. Hurricane Katrina was a 100-year-storm. The nameless floods that we are presently recovering from are 1,000-year-floods. The next one just may be a 2,000-year-event, and we must be prepared.
Our bodies and souls and bank accounts can’t keep doing this. We can’t continue losing our homes, and businesses and shirts, just to build it all back…. the same way.
We must take a step back, zoom out and strategically rebuild as a system. Then we can safely live through the floods and hurricanes that are a part of life here in Louisiana. Sure, we’ll have to take a week off and dust ourselves off. But if we rebuild so that we can live harmoniously with the forces of nature, and the manmade repercussions of climate change, then our future recoveries will be a lot swifter and easier on us.
We need a massive reforestation of Louisiana. Mature, native, water-loving trees like Live Oaks and Bald Cypress drink up to 1,000 gallons of water per day and should be as common and beloved a site in our urban and rural landscapes as Saints bumper stickers. One huge impetus behind founding SOUL is the very large goal of replanting New Orleans, the most deforested city in the U.S.! But rural Louisiana suffers from deforestation as well, largely due to short-sighted development of subdivisions and commercial areas that raze the forest and level the land before construction. Trees are essential to our resilience as they absorb stormwater into their root systems and transpire it back into the air. A mature tree produces enough oxygen for ten people, and can lower our air temperatures by up to two degrees. The benefits of trees are endless, and our futures rely on them.
It’s time to respect the gravity of gravity. It there’s one thing we can always count on, it’s that water will always travel downhill. Thus, it is vital that water has an unobstructed path to its nearest floodplain or basin. Rural Louisiana has many flood plains and small water bodies like creeks that are bisected by roads. During heavy rains these spots turn into dams and cause massive flooding as water seeks a lower point of gravity.
New construction should be raised to a level accommodating a 2,000-year storm. Considering how quickly our disasters are growing in intensity and frequency, it only makes sense that we should build new homes and businesses according to future storm levels. We’re recovering from a 1,000-year flood, so let’s rebuild to a 2,000-year disaster this time. Many of the structures that were damaged were built at grade on slab. Cities must stop allowing development that ignores our hydrology and natural history, for the sake of developers maximizing their profits.
We need to integrate “green infrastructure” into every aspect of our lives. If you’re not already familiar with this term, it refers to infrastructure that mimics natural systems and harnesses stormwater at its source. Essentially its goal is to get water back into the ground and into the water table.
Like grey infrastructure, such as canals and roads, green infrastructure must be built at a meaningful scale and properly integrated into the systems we call cities and parishes. This could mean a city repaving its streets with permeable asphalt, or grading streets so their water drains into a detention area, NOT toward homes and businesses. When we cover the earth with impermeable surfaces like concrete and rooftops, water can’t get back into the ground to the water table; eventually the water table shrinks and subsides, taking our topography down with it. If the water can’t permeate the ground, then it floods during large rain events.
Every new street, parking lot or sidewalk should be constructed of materials that water can penetrate. Every road should be part of a larger comprehensive drainage plan, eventually sending water back into the water table.
All of the above concepts are pretty simple. But they involve changing our consciousness around resilience from the citizen level to the Governor’s mansion; and they require the decision makers at the city, state and even regional levels sitting down to the same table to address our road, hydrology, and forestry systems as interconnected and reliant on one another.
One thing is for sure, we citizens of Louisiana want to stay in this strange, beautiful gumbo of a place we choose to call home. But we can’t keep crossing our fingers that we won’t have to shoulder another disaster that didn’t have to happen.