What Raingardens Do
When rain falls on an impervious surfaces (areas like roofs, sidewalks, and roads) it cannot soak into the ground and rushes toward the lowest point, hopefully a storm drain. The rain picks up dirt and debris, oil and gas leaked from automobiles, lawn fertilizers and pesticides, and chemicals from industrial and commercial activities. These pollutants are pumped out into Lake Pontchartrain.
A raingarden is designed to collect and infiltrate this storm water runoff before it can enter a drain. A raingarden is a shallow landscaped depression created by excavating existing soil and replacing some of it with porous material, like sand and gravel, and nutrient-rich material like compost. The area is then restored with many kinds of plants.
What Raingardens Do
In New Orleans, our pumping stations account for 40% of our municipal greenhouse gas emissions and are expensive to operate. Raingardens reduce the use of costly and greenhouse-gas producing pumping stations.
- Deep plant roots and a porous soil mix store and absorb water, 30% more than a conventional lawn.
- Many pollutants are removed through physical, chemical, and biological processes like settling, accumulation by plants, and most importantly activity of soil micro-organisms.
- Plant species native to the region or from a wetland are accustomed to heavy and fluctuating rainfall, decreasing maintenance needs.
- Raingardens support a greater variety of wildlife than typical landscaping while preventing the stagnant street ponding that breeds mosquitoes.
- Water and the water cycle become visible and beautiful aspects of the landscape.
- Improved aesthetics increases the quality of life in and fosters pride of an area.