Design of urban runoff pollution control based on the Sponge City concept in a large-scale high-plateau mountainous watershed: a case study in Yunnan, China

Abstract

China recently commenced the Sponge City initiative for the effective management of urban stormwater runoff. Numerous studies have been carried out to evaluate the cost-effectiveness of low impact development (LID) practices in Sponge City planning and implementation. However, most of the studies were at the siteor subcatchment scale, and few were conducted at the watershed scale, given the dramatically increased routing complexity and number of decision variables. This study demonstrates the cost-effective Sponge City planning process for a 25.90 km highplateau watershed in southwest China. The Stormwater Management Model was coupled with the System for Urban Stormwater Treatment and Analysis Integrated (SUSTAIN) model to perform both continuous simulations and watershed-level optimization analyses, using the reduction of 85% annual runoff volume as the optimization target. Based on over 11,000 optimization runs, a nearoptimal aggregated LID scenario was identified for each subcatchment. The aggregated LID size was first converted into a generic LID storage volume for individual subcatchments, and the storage volume was then disaggregated into site-level LID layouts regarding specific site conditions. The disaggregated LID layout yielded an annual average runoff volume reduction of 87.61% and close to 85% reduction for the annual average total suspended solids, total nitrogen, and total phosphorus loads. The systematic approach outlined in this study could be used for watershed-level Sponge City planning and implementation analyses in other cities. This is an Open Access article distributed under the terms of the Creative Commons Attribution Licence (CC BY 4.0), which permits copying, adaptation and redistribution, provided the original work is properly cited (http://creativecommons.org/licenses/by/4.0/). doi: 10.2166/wcc.2019.120 ://iwaponline.com/jwcc/article-pdf/doi/10.2166/wcc.2019.120/641877/jwc2019120.pdf Zhenyu Zhang Junjie Gu (corresponding author) Ping Ning Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650093, China E-mail: [email protected] Zhenyu Zhang Jian Shen School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China Guoshun Zhang Wenjing Ma Nanjing Innowater Environmental Technology Ltd., Nanjing 210039, China Lei Zhao School of Information Science and Technology, Yunnan Normal University, Kunming 650092, China