1D-2D flood modelling using PCSWMM

• Main Author: Lim, Yin Shuen
• Other Authors: Chua Hock Chye Lloyd
• Format: Final Year Project
• Language: English
• Published: 2014
• Subjects: DRNTU::Engineering::Environmental engineering
• Online Access: http://hdl.handle.net/10356/60741
• Institution: Nanyang Technological University

To overcome the limitations of 1D modelling, this report investigates the capabilities of an integrated 1D-2D hydraulic/hydrology model, and the role of 2D hydraulic modelling in flood modelling, using PCSWMM 2D. PCSWMM 2D is a relative new system developed in 2011, integrating traditional 1D model, SWMM 5.0, with 2D overland flow modelling capabilities. In this study, PCSWMM 2D was tested on an artificial catchment using both the 1D and 1D-2D modelling approach to better understand the accuracy and features of 2D modelling, integrated with 1D. In this study, it is shown that the performance of 1D-2D model is similar to that of 1D and hydrographs produced by the 2D model appear less noisy. The good agreement between the 1D and 1D-2D models provides a measure of confidence that the 1D-2D model is able to simulate the test case well. In addition, to evaluate its applicability to real locations and better understand of the model set up procedure for a real application, a 1D-2D model of PCSWMM was tested on a real sub-catchment in Singapore. The 1D-2D model results were coherent to data available, thus illustrating the ability of 1D-2D model to simulate a real sub-catchment well and its potential for modelling urban flooding. With the available features such as obstruction layer and 2D meshes, the 1D-2D model is feasible for urban area and overland flows. Therefore, 1D-2D modelling using PCSWMM is fairly accurate and practical to use for real life simulations. However, few limitations were observed. The minimum slope required for conduits and the wall-like bounding layer of 2D modelling may lead to inaccuracy of the simulations. Nevertheless, this study showed that integrating 1D and 2D modelling approach using PCSWMM 2D has many advantages; it allows seamless transition between 1D and 2D modelling, easy to use, feasible and able to simulate the study area well.