A Distributed Model For Urban Water Demand Prediction

The prediction of urban water demand is likely to play a significant role in the planning of urban water supply and drainage pipe network.The traditional water demand forecasting methods,including the water index method and the fuzzy water demand prediction model,are widely used with some deficiencies.The water demand prediction results varied among different water quantity indexes with subjectivity.The prediction results by fuzzy water demand prediction model,with fuzzy model structure,are lack of spatial distribution.Meanwhile,the process of urban water demand is closely related to the land use of urban unit.The difference of intensity and characteristic of water demand is obvious among different land use types.In this paper,a distributed urban water demand prediction model was established based on the relationship of water demand process,considering of the eight types of urban construction land use data and three types of major water demand data.In this model,the water demand parameters of every urban construction land unit were calibrated by PEST,and the rationality of parameters was analyzed.We observed the stability of the water demand parameters in the model while the results showed great similarity with different calibration period in the same validation period.The water demand of Xiamen and its spatial distribution in 2020 were predicted by the distributed water demand prediction model.The results showed that the water demand of Xiamen in 2020 will reach to 366.57 million tons,which will increase by 24.2%than that in 2014;the water demand intensity of residential land and industrial land will be greater than other types of construction land;the water demand intensity of residential land in Xiamen Island will be greater than the other residential land.The simulation results proved that the spatial distribution of water demand has positive correlation with population density in urban area.We observed the great difference of water demand intensity among different types land use with great difference in the process of urban water demand.The results also showed the excellent performance of the distributed model for urban water demand prediction both in calibration and validation when applied in Xiamen urban water demand prediction.Furthermore,the natural and artificial drainage volume of a typical catchment area in Xiamen island was calculated with the water demand data of Xiamen in 2020 predicted by distributed urban water demand prediction model.