Hydraulic and Hydrologic Performance of Residential Rain Gardens

Abstract

AbstractAccelerated stormwater runoff creates environmental problems in many urban communities. Methods of reducing runoff for individual residences are available, but are often recommended without sufficient analysis. For example, many states provide guidance on creating rain gardens, but few include information about how well rain gardens actually work. An analysis algorithm is presented to evaluate rain garden effectiveness at reducing stormwater runoff by promoting infiltration, evaporation, and evapotranspiration. Example simulations are presented based on an Ohio meteorological record. Results indicate that garden effectiveness is dominated by infiltration. Evaporation and evapotranspiration play minor roles in reducing runoff. Results also indicate that current rain garden design recommendations are often too conservative. Even for low permeability soils, rain gardens can be more effective than currently assumed. Common depth recommendations are reasonable, but area recommendations are also conserv...