Source: Stephanie Bruno, “More trees mean less flooding, urban forestry advocate says,” The New Orleans Advocate
New Orleans, LA (August 12, 2017) – Susannah Burley became so committed to the idea of using rain gardens, retention ponds and appropriate street plantings to reduce flooding that she founded new nonprofit, SOUL (Sustaining Our Urban Landscape) NOLA.
“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 recent catastrophic flooding in the City 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.”
“There are so many different options for green infrastructure, but right now we are focusing on tree planting. Did you know that New Orleans is the most deforested city in the United States?” Burley asked. “Estimates are that New Orleans can accommodate a million more trees than we currently have — a million! Though our ‘Ya Dig?’ program, we planted 190 trees last year and will plant 600 this year. Once the neighborhoods we are working with are reforested, we’ll expand to more neighborhoods.”
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.”