Study On Interval Water Demand Prediction And Optimal Allocation Of Water Resources In Liuzhou City

Water resources shortage could seriously hinder economic development and social progress.In order to better maintain the coordinated development of economic society and water resources,water resources must be reasonably planned and utilized.Based on the present situation of water resources exploitation and utilization,water supply and demand of Liuzhou City are predicted.The allocation of water resources in Liuzhou City in 2025 and 2035 is studied in order to provide a scientific basis for the development and utilization of water resources in Liuzhou City.The main research contents and results are given as follows:(1)Combining BP neural network with normal interval estimation,a new prediction model of water demand is proposed.The model overcomes the problem of large deviations in prediction results due to the instability of the BP neural network itself,and exhibits better prediction accuracy and robustness.By comparing with the traditional prediction methods,it is found that the relative error of the obtained result is significantly smaller than those based on the traditional prediction methods,indicating that the prediction accuracy of the model is significantly improved compared with the traditional prediction methods.In addition,the interval values predicted by the model leave room for decisionmakers to a certain extent,which is more in line with the actual economic and social development of Liuzhou City.(2)According to the actual situation of water resources development and utilization in Liuzhou City the relevant planning reports of Liuzhou City,and the current situation of water supply in 2019,the water availability in 2025 and 2035 in the planned year is predicted.Combined with the prediction results of water demand in the planning year by the new model,the balance analysis of water supply and demand is carried out.The results show that in 2025,under the condition of 50% water frequency,the whole Liuzhou City is in a state of no shortage of water.Under the condition of 75% and 95% of the water frequency,the whole Liuzhou City is in a state of water shortage.In 2035,under the condition that the frequency of incoming water is 50% and 75%,the whole Liuzhou City is in a state of no shortage of water.Under the condition of 95% of the frequency of incoming water,the whole Liuzhou City is in a state of water shortage.In addition,under the condition of a water frequency of 95%,the degree of water shortage in2025 is more serious than that in 2035.(3)Taking economic,social and ecological benefits as the objective functions,and water supply and demand as the constraint conditions,the multisource and multi-objective optimal allocation model of water resources in Liuzhou City is constructed.The genetic algorithm(NSGA-II)is used to solve the model,and the water resources allocation schemes under different water inflow frequencies in 2025 and 2035 are obtained.The results show that under the condition of 75% water inflow frequency in 2025,the water shortage users are agriculture,construction and service industries.Under the condition of 95% water inflow frequency in 2025 and 2035,the water shortage users are industry,agriculture,construction and service industry.In the two years,the water shortage rate of agriculture is the largest,followed by construction and service industry,and the water shortage rate of industry is the smallest.The proposed allocation scheme is in line with the principle of water resources allocation,which can provide a scientific guidance for the planning and utilization of water resources in Liuzhou City.