Monitoring and modeling impacts of a rain garden on the University of Georgia campus

I collected samples and hydrologic data from the inflow and outflow of a campus rain garden for 10 storm events over eight months. The rain garden consistently decreased loads of sediment, ammonium, and total phosphorus and consistently increased loads of nitrate. I also modeled the collective impacts of rain gardens in two Athens-area watersheds for a 10-year period using SWAT. The urban watershed experienced frequent large peak discharges in storm events, while the forested watershed showed less frequent, lower peak discharges from those same storms. Routing 30% of runoff generated by an urban watershed through rain gardens showed reductions in peak discharge of 30% and did not overtreat discharge or reduce peak discharge below that of a forested pre-development watershed. Numerous barriers exist that prevent the widespread installation of rain gardens across Georgia, and I discuss the role of policy in removing those barriers.