Simulation And Countermeasures Of Water Footprint Based On System Dynamics In Guanzhong Area

Water is the key element to support human society and economical development.Water footprint is a comprehensive measurement of water consumption and occupation in a region.In this paper,the water footprint of Guanzhong area is divided into four parts:agricultural water footprint,industrial water footprint,domestic water footprint and ecological water footprint to study the water footprint components of Guanzhong area and the dynamic changes in this region.The agricultural water footprint is the most important part of this accounting and is calculated using the Penman-Monteith equation recommended by FAO 56.The other three types of water footprints are calculated using normal standards.The system dynamics method was used to construct the water footprint simulation model of Guanzhong area.The model covered the blue water and green water footprint,and the scenario analysis method was used to set four development scenarios to simulate the future water footprint dynamics.It provides countermeasures and advice for water footprint regulation,sustainable socio-economic development and sustainable use of water resources in Guanzhong area.The main conclusions of this paper are as follows:1)The water footprint of Guanzhong area showed a downward trend,from 15.37 billion m~3in 2000 to 13.61 billion m~3 in 2015,with an overall decline of about 11.5%.Agricultural water footprint accounts for the largest proportion of water footprint in Guanzhong area,accounting for 86.9%,followed by industrial water footprint of 6.4%,domestic water footprint of 5.9%,and ecological water footprint of 0.8%.The green water footprint of wheat is the main body of the agricultural water footprint accounting for about 65%,followed by corn and apple.In addition to the higher proportion of apple water footprint in fruit production,the remaining proportion is less than 1%.The four highest water-consuming crops in Guanzhong area are cotton,rapeseed,peanuts and wheat.2)The system dynamics method was used to construct the water footprint simulation model for Guanzhong area from the year 2000 to 2015.The system was divided into five subsystems:agricultural water footprint,industrial water footprint,domestic water footprint,ecological water footprint and water supply subsystems,which contain 122system variables.The Vensim PLE software was used to draw the stock and flow diagram,the structure and dimensional consistency of the model were tested as well.The results showed the errors of most variables were within 10%,and the model is of good performance and high reliability.3)Scenario analysis was used to set up four development scenarios to forecast the water footprint of the Guanzhong area from the year 2016 to 2025.Under the current water resources condition,the four scenarios showed that the total blue water footprint and water supply and demand ratio in Guanzhong area were decreasing.Increasing the infiltration coefficient and the irrigation water utilization coefficient are essential for reducing agricultural water consumption.Appropriately reduce wheat planting area and increase the yield per unit area,and high water-consumption crops such as cotton,canola and peanuts can effectively control the agricultural water footprint in general.Industrial,domestic,and ecological water use did not have a significant impact on the total blue water footprint under high-speed development scenarios.