Simulation of flow process in urban double layered river channels: Case study of the South Branch of Campus River in Tsinghua University

Through the installation of various water facilities for comprehensive water flow regulation, urban double-layered river can achieve flood discharge, rainwater resource utilization, and ecological base flow guarantee, taking into account both safety and hydrophilic aspects. However, the double-layered river channels exhibits more complex hydraulic connections than traditional river channels in the horizontal-vertical-lateral dimensions, posing challenges for numerical modeling and flow simulation. Currently, there are still few studies focused on simulating the flow process of urban double-layered river channels. This study takes the drainage area of south branch of the campus river in Tsinghua University as the research object and considers various water facilities such as gates, holes, weirs, and pumps to construct a water flow simulation model for urban double-layered river channels. Based on the rainfall observation data of small weather stations on the campus, the process of water depth changes in front of the South Branch terminal control gate and flow after the gate are simulated. Results show that the established model can simulate the flow process of double-layered river channels well with high level of credibility.