An example of the benefits of runoff reduction using GSI in a highly urbanized watershed is the McDaniel Branch project in Atlanta5. The project site, the former location of an early public housing project, had been abandoned and overgrown and provided very little community value. The stormwater improvement project, part of the city’s overall watershed improvement program, was seen by the city to demonstrate the possibilities of urban watershed restoration — to address flooding and water quality but also improve community resilience and address equity. This project includes approximately 1,100 linear feet of stream restoration, rerouting of several storm sewers that discharged directly into McDaniel Branch into a series of ponds and constructed wetlands.
These best management practices capture stormwater runoff
from the areas sur- rounding the site and also divert part of the first flush from an existing 66-inch storm sewer that drains the upstream portion of the drainage basin. The development of a site management plan following construction that addresses the wetland and upland meadows, ponds, invasive species control, mosquitoes, wildlife including geese and beaver, and public access, has resulted in this area now having diverse vegetation and aquatic life that has attracted wildlife that could not otherwise be conceived in a dense urban setting.
Where the project site was once an eyesore and local nuisance, it has been transformed into a destination location that is now visited by residents and wildlife enthusiasts alike and has been designated a Wildlife Sanctuary by the Atlanta Audubon Society.
With the dramatic increase in intensity of storm events in recent decades due to climate change, addressing resiliency to extreme wet weather events is a major concern. GSI can be an effective tool in reducing peak flows and capturing runoff from major wet weather eventsin addition to providing water quality and stormwater runoff storage for small storms events. It can also be part of a holistic solution that provides an amenity to the community and improves the livability of residents.
1. U.S. Environmental Protection Agency, National Water Quality Inventory Report to Congress, https://www.epa.gov/waterdata/national-water- quality-inventory-report-congress, 2022
2. U.S. Environmental Protection Agency, Flood Loss Avoidance Benefits of Green Infrastructure for Stormwater Management, December 2015
3. Maragno et al, Fine-scale analysis of urban flooding reduction from green infrastructure: An ecosystem services approach for the management of water flows, Elsevier, 2018
4. Trust for Public Land, Natural Solutions Tool, Greater Chicago, A Watershed Approach, https://web.tplgis.org/chicago_nst/, 2023
5. Anwer Ahmed, PE, DWRE & Susan Rutherford, Enhance Biodiversity, Community Resilience, and Water Quality Benefits through Effective Stormwater Wetland Management,