Dynamic Modeling And Simulation Of Water Supply And Demand In Jiangs

Reasonable forecasting of water supply and demand is the basis for optimal allocation of water resources.In this paper,production function and system dynamics are combined to establish water supply and demand models for domestic,industrial and agricultural water systems in Jiangsu Province,and the adaptability of accelerated depreciation method in water industry is explored.Scenario analysis is used to project the supply and demand balance for the three types of water system over the next 15 years with different development scenarios.Through comparison,the development scenarios that meet both the connotation of sustainable development and the reality are selected.The domestic water demand function under the combined effect of resident population,per capita disposable income and water-saving consciousness is investigated.The VES production function is used to describe the domestic water supply.Combined with the background of"Three-child policy"to predict the future population trends,four different water demand scenarios are designed,and the corresponding water supply production scheme is given The industrial water demand is expressed as the product of the water demand for10,000 yuan of industrial value added and the industrial value added,and industrial water supply is described by the C-D production function.The industrial water demand is examined in the context of the decreasing trend in water demand for 10,000 yuan of industrial value added and the increasing trend in industrial GDP value added.From the water supply side,the reasonable range of industrial water supply volumes and the way to regulate them are discussed.The agricultural irrigation water demand is expressed as the product of effective irrigated area and average irrigated acreage water consumption,and the agricultural water supply is described by a fixed replacement ratio production function,and fixed assets are depreciated by constant rate balance method.Set different development models for agricultural water supply and demand,compare and select scenarios that are more in line with agricultural development.The domestic water study shows that maintaining current trends and input levels will result in an oversupply of water in the future.The ideal water demand scenario is one in which high per capita disposable income growth is accompanied by a high rate of growth in consciousness of water-saving.The straight-line depreciation model requires an investment of3.32I_D1（t）and2.83I_D1（t）in 2020-2027 and 2028-2034 respectively.The accelerated depreciation model requires an investment of3.2I_D2（t）and2.4I_D2（t）respectively.Labor input should be set at 1.2P_D（t）in 2020-2026 and P_D（t）in 2026-2034 to achieve balance between domestic water supply and demand.Industrial water research shows that at current factor input levels,the supply of industrial water with the straight-line depreciation method is consistently less than the demand;the supply is less than the demand from 2010-2027,and after 2028 the supply is greater than the demand with the accelerated depreciation method.The reasonable combination of industry investment and labor input is 0.5I_I（t）and P_I（t）.Agricultural water research shows that a sustainable development model is more appropriate for future agricultural development.By 2034,the effective irrigation area of Jiangsu Province will be6446.26×10⁴ mu,the average irrigated acreage water consumption will be reduced to 395m³,and the investment and labor input will be8×10⁸ yuan and 0.173×10⁴people,so a balance between agricultural water supply and demand can be achieved.The simulation results also show that the accelerated depreciation method is a good match for the supply and demand water industry and can provide a reference for the implementation of accelerated depreciation method in the water industry.A combination of production function and system dynamics modeling approach for water supply and demand studies is feasible.All three production functions have a good probability of matching demand.