A GIS-based water distribution model for Zhengzhou city, China
Many water companies in China are developing GIS as a computer-based tool, for mapping and analyzing objects and events that happen on a water distribution network. However, only a few companies have taken a further step to develop a hydraulic model based on GIS, and Zhengzhou Water Supply Corporation is one of them. The WaterGEMS V8 XM from Bentley is used to develop the hydraulic model for the water distribution network in Zhengzhou city, which has a population of over 3 million. During establishment of the model, some of the data extracted from GIS are missing, abnormal, and redundant and require careful screening, searching, and judging. Model calibration is performed after a sensitivity analysis. Peaking factor and pipe roughness coefficient are key model parameters to calibrate. In calibrating peaking factors, the distribution system is divided into 5 operation districts with different types of water usage. To calibrate pipe roughness coefficients, the system was divided into 4 water supply districts with different attributes of pipelines. Finally, a case study of pipe layout evaluation it shows the hydraulic model to be a powerful tool for water supply management.
Keywords: GIS, hydraulic model, model calibration, water distribution network