Green Infrastructure Rain Garden GIFMod Stormwater Management
Abstract:
Traditional stormwater management has focused on reducing urban flooding through the collection and channeling of stormwater; however, this has led to a series of undesirable environmental impacts downstream. More modern stormwater managements are now beginning to be utilized, known as green infrastructure. Rain gardens are green infrastructure features used to remove stormwater in urban areas by detaining and retaining runoff. GIFMod was used to model the hydrological performance of residential rain gardens based on the predominant soil characteristics in regions of Pennsylvania. The objectives of these simulations were to analyze the sensitivity of basic rain garden design factors and explore the variability in rain garden performance throughout Pennsylvania, based on the maximum ponding depth and ponding time of the rain garden. While rain garden hydrological performance varies depending on native soil, it was found that Pennsylvania soils can often accommodate stormwater loading ratios much larger than those currently recommended. Additionally, it was concluded that evapotranspiration provides negligible contributions to runoff reduction in residential rain gardens. It is recommended that the rain garden design sizing guidelines outlined in the Pennsylvania Stormwater Best Management Practices manual be revised, and rain garden sizing be determined based on the infiltration rates of the native soil compositions.
