Modeling the Urban water Demand in Mashhad Based on Fuzzy RegressionModel

Supplying the tap water in Mashhad city is going to face serious challenges and threats in the future. The population of this city is more than 3 million and its pilgrim is estimated at 25 million per year. Urbanization in Mashhad city and around it is growing. The range of this study is including Mashhad city along with Golbahar, Chenaran, and Ghuchan. The excessive development of these cities leads Mashhad city to physical water scarcity in long term. For this purpose, the effective factors on water demand in Mashhad city have been identified. For this purpose the most desirable urban water demand function has been extracted, by using the Stone Gary method. It is worth mentioning that in order to investigate economic and social uncertainties in the model, the results of previous researches and the opinion of experts have been used; then, the effective uncertainties on the elements are determined by using the fuzzy linear regression model. Finally, urban water demand function of the Mashhad city for 2010-2017 is calibrated and used to estimate water demand from 2018 to 2070. The results show that the demand function of Mashhad city is strongly influenced by the time between receipt of the bill and the household composition. So these two factors can be considered for demand management. At the end, the model accuracy is based on the R^2 that is equivalent to 0.921 which indicates the proper performance of this model in predicting urban water demand.