A Method to Identify Key Sub-catchments for LID Placement Based on Monte Carlo Sampling

Abstract

Low impact development (LID) can treat excess urban runoff and improve the performance of urban drainage system. LID located in different sub-catchments has quite different effect. However, using optimization algorithm to find the key sub-catchments will cost much computing resources and time. This research proposed a method to rapidly identify key sub-catchments for LID placement by a new index called Rank Score. A case study area in Kunming, China is adopted to test the validity of the method. The application of Rank Score is found to be effective and key sub-catchments are recognized to generate optimized solutions. It is discovered that compared to the average of Monte Carlo samples, optimized performance indices are 41.7%, 26.8% and 42.4% less in terms of the amount of flooding, CSO and shock to WWTP respectively. The numeric features and spatial characteristics of Rank Score distribution are discussed as well.