Modelling low-impact development on urban drainage systems under complexity

• Main Author: Cheam, Yu Juen
• Other Authors: Qin Xiaosheng
• Format: Final Year Project
• Language: English
• Published: 2019
• Subjects: DRNTU::Engineering::Civil engineering
• Online Access: http://hdl.handle.net/10356/77384
• Institution: Nanyang Technological University

Low-impact development (LID), also known as a sustainable urban drainage systems, refers to a system that improve the stormwater runoff management by imitating the natural hydrologic processes. Many past studies have shown LID effectiveness in improving water quality, reducing stormwater runoff and recreating green spaces in urban areas. However, it is still a challenging issue to determine how many LID controls should be implemented to maximize the performance of LID in the catchment, considering the cost factor. Hence, this paper examine the effectiveness of incorporate LID controls in urban planning by evaluating the hydrologic performances of LID and the cost of LID. Storm Water Management Model (SWMM) software is used in this study to simulate the effect of implementing a different percentage of LID controls (Green roofs, Bioretention cells, Permeable pavement) at the artificial catchment area. The cost of LID per unit sqm is calculated using a costing tool by Toronto and Region Conservation (2013). Three different MCDA methods (AHP, TOPSIS, WSM) are used to compare the 8 different alternatives to identify the best alternatives with respect to the weighting factor set. In this study, the hydrologic performance of LID is more important than the cost of LID (weighting factor of performance larger than cost) and therefore the alternatives with 80% of LID being implemented (Case 8) is chosen as the best alternative.