Assessment of low impact development for managing stormwater with changing precipitation due to climate change

► Simulations illustrate relationships between land use, precipitation, and stormwater. ► Synergistic effect of increased precipitation and impervious cover on stormwater. ► LID provides co-benefits by increasing resilience to climate change. Evidence suggests that built environments will need to function under climatic conditions different from the recent past. Observed warming temperatures and changes in precipitation already suggest that historical observations and personal experience may not be reliable guides to future conditions. Yet, uncertainties remain about future climatic conditions, particularly at local and regional scales where land use planning decisions are made. Faced with this uncertainty, responding to climate change will require identifying key vulnerabilities of the built environment and developing adaptive strategies for reducing the risk of harmful impacts. One area of potential vulnerability is stormwater management. Increased precipitation due to climate change could exacerbate the impairment of surface waters due to increases in stormwater runoff. This study considers the potential effectiveness of low impact development, specifically compact development with decreased impervious cover, for reducing stormwater impacts on surface water under changing precipitation patterns. The study location is a redevelopment project south of Boston, MA, USA. A simple stormwater model, SGWATER, is used to assess the sensitivity of stormwater runoff and pollutant loads to changes in impervious cover, precipitation volume, and event intensity. Simulation results suggest that when expressed on a constant percent basis, stormwater runoff is most sensitive to changes in site impervious cover, followed by changes in precipitation volume and event intensity. The study illustrates, in a simple but quantitative way, the potential benefits of a common low impact development practice for increasing the resilience of communities to changing precipitation patterns.