Using a Complex TMDL Modeling System to Evaluate Water Quality Improvement in Receiving Waters Due to Sponge City Construction of Zhenjiang City, China

摘要

This paper describes the development of a complex modeling system used for planning, design, and evaluation of sponge city construction projects in Zhenjiang City, Jiangsu Province, China. This modeling system adapts two models to simulate hydrology and pollutant (point source and non-point source) transport in watersheds. SWMM is used for urban watersheds and HSPF is used for rural watersheds. Another two models are used for receiving waters. HEC-RAS is used to simulate hydraulics and water quality in one-dimensional rivers and EFDC is selected to simulate three-dimensional hydrodynamics and water quality in three rivers and Jinshan Lake. This paper discusses the coupling process between watershed models and receiving water models, as well as calibration and confirmation for each sub-model. Finally, this study uses TMDL (total maximum daily load) process for this modeling system to evaluate the performance of water quality improvement in receiving waters after LID (low impact development) projects implementation. Effect of sponge city construction projects on water quality improvement in receiving waters is analyzed from modeling results and further pollution control work is suggested for the next-phase task of sponge city construction.