Hydrologic response of sustainable urban drainage to different climate scenarios

Sustainable Urban Drainage Systems (SUDS, also sometimes referred to as green infrastructure or low impact development) to enhance or replace conventional stormwater management practices have become a centerpiece of many urban stormwater management plans. This study investigates the behavior of urban runoff under different long-term climate scenarios with various densities of SUDS implementation using three kinds of methods: traditional hydrologic analysis, Chernoff face analysis, and statistical tests and a number of different parameters to quantify SUDS behavior. Long-term (12-year) rainfall and evaporation data from ten different cities throughout the country were used to represent distinctive potential future climate scenarios. These data were input into a set of SWMM models of a 3.16 km2 urban catchment, with each model having a different SUDS implementation. Under each set of SUDS implementation, results using different climate inputs were compared. The capability of SUDS to perform under varying climate scenarios provides an estimate of the resilience of the different SUDS implementations to potential long-term climate change. Results showed that both climate scenarios and SUDS scenarios have a strong impact on catchment’s hydrologic response. Even though climate scenarios are more dominating, the implementations of SUDS are capable of overcome the change in climate scenarios to a certain extent, which indicates that implementing SUDS can help to improve urban catchment’s resiliency against climate change. The influence of SUDS on hydrologic response, as described by various indices, was observed at different time scales, from hourly to annually. Differences in hydrologic response with SUDS between different climate scenarios suggest that SUDS implementation can be optimized to improve performance for different long term climate projections