Optimal selection and placement of sustainable drainage solutions in Cau Bay river basin

Abstract

    Recently, increased impervious areas due to urbanization have induced increased surface runoffsentering into the drainage system in Cau Bay river basin. Sustainable drainage solutions - LID (LowImpact Development) on subcatchments have high efficiency on both reducing flow peak andlengthening concentration time. This paper aims to couple non sorted genertic algorithm (NSGAII) withStorm Water Management Model (SWMM) to find optimal LID selection and placement in Cau Bayriver basin. The optimal LID soultions ensuring both maximum peak flow reduction and minimumimplementation cost were plotted together as a benefit - cost curve. An optimal LID solution combinedthe number of bioretentions, permeable pavement, tree well and flow through plant tree planters. Threeoptimal solutions with peak flow reduction of 10%, 24% and 46% indicated that there was significantvariation in the number of each LID type: namely, percentage of tree well was in the range from 73.3%to 77.4% while permeable pavement contributed only 1%. In constrast, there was small differenceamong area percentages of each LID type.