The conventional drainage system relies on the design of a network of curb gutters and underground pipes. Such gray infrastructure may not be environmentally suitable, as they do not fully avoid problems but transfer the problem leading to intense flooding downstream. In addition, such drainage systems are based on historical records of precipitation, assuming the precipitation intensity would remain constant. As the precipitation intensity and frequency are expected to increase in the future due to climate change within the Lake Erie Basin, the capacity of the drainage system designed using the conventional design approach may not be able to accommodate the increased runoff resulting in the failure of storm drainage systems. Consequently, there is a critical need to explore the extent to which GI or LID can be beneficial over the gray infrastructure to reduce flooding problems downstream. Therefore, this study is examining communities preferred LID i.e., raingarden in residential area and Permeable Pavement in commercial area and the extent of runoff reduction on different implementation level in the Town of Willoughby-HUC 12 watershed of Lake Erie Basin. After extensive collaboration with stakeholders and communities, these two LIDs were chosen. The effects of two LID strategies (permeable pavement, and rain garden) on urban floods are evaluated and contrasted with the traditional drainage system design. For a comprehensive evaluation of the LID approaches, a variety of storm occurrences with various amounts of rainfall and durations are evaluated. When compared to the design of a traditional drainage system, the results are quantified by the overall stormwater runoff reduction that occurs after a storm event. Results showed an increased peak runoff reduction, from 15% to 62%, with increased implementation levels from 20% to 100% from the use of permeable pavement and from 6% to 27%, with increased implementation level from 25% to 100% for the raingarden. In the mean time, various scenarios of CMIP5 and CMIP6 climate models are used to downscale the climate data for the 21st century to investigate whether the proposed LID would mitigate the climate change impact to minimize the increased runoff. This study aims to effectively communicate the key messages regarding the implementation of Low Impact Development (LID) in the field, with the goal of benefiting the community to combat the climate change effect in future.
