Residential Rain Garden Performance in the Climate Zones of the Contiguous United States

Rain gardens are one of the technologies often recommended for residential stormwater management. It is not difficult to find rain garden design recommendations, but more difficult to find quantitative assessments of how effective these gardens are at reducing runoff. Analysis is presented to illustrate how well a common rain garden design would work when subjected to the hydrological and meteorological extremes experienced across the contiguous United States. Results of 3-year hourly continuous simulations indicate that, because of variations in the amount and pattern of precipitation, the effectiveness of comparable rain gardens would vary from about 51.3 to 99.8% across the contiguous United States. Identical gardens would be least effective in Atlantic and Gulf Coast states and most effective in northern Midwest and Mountain states. Results also indicate garden evapotranspiration and evaporation have a negligible impact (<1%) on runoff reductions. This is true even for the warm, sunny climates of southwestern states. Results also indicate that, if common design recommendations on minimum infiltration rates are followed, it would be unlikely for standing water to persist in gardens long enough for mosquitoes to breed. (C) 2016 American Society of Civil Engineers.