Research On Regional Ecological Water Requirement Model

Water resources play an important role in the development of human society.However,with the population and urbanization increasing,the intensity of water resources is more and more rigorous.At the same time,unreasonable use of water resources and water pollution have also emerged.It is necessary to allocate water resources rationally in order to relieve water stress and ensure sustainable water use.For the purpose of this goal,understand the status quo of water use is an indispensable link.Based on the analysis of the current situation,many scholars have explored the regional ecological water demand:whether the use of water resources is reasonable,whether it meets the needs of economic development,and whether the use of water resources can be improved.In the previous studies,the composition of ecological water demand was unclear,the methods were not uniform,and calculation problems were inaccurate.In order to solve the above problems,we propose an ecological water demand model.Taking the Hanjiang River Basin as an example,we collect and collate relevant data,use the GIS spatial analysis method to analyze and evaluate the ecological water demand in the Hanjiang River Basin.The main contents are as follows:(1)We innovatively set the ecological water demand of a region as non-biological water demand and biological water demand,and clarify the composition of ecological water demand.Between them,abiotic water demand indicates to the amount of water required by the regional ecosystem itself without the participation of living organisms;biological water demand represents that the amount of water needed by the regional ecosystem with the participation of both animals and plants.(2)Based on the definition of regional ecological water demand,this study has created a unified ecological water demand model,and has divided the regional ecological water demand model into two parts:the non-biological water demand model and the regional ecological water demand model.Between the two,non-biological water demand model includes river sediment transport water demand mode,river lake evaporation water demand model,soil water demand model and regional urban industrial water demand;And the water model includes the wetland habitat water demand model,the vegetation transpiration water demand model,the crop water demand model,and the urban life water demand model.(3)We have researched ecological water demand of the Hanjiang River Basin and evaluated the ecological water demand satisfaction of the Hanjiang River Basin.By the researches,we have reached the following conclusions:(1)The ecological water demand model is mainly to evaluate the amount of water needed in a specific region.According to the research on the results of ecological water demand,it tells us how much we can adjust and regulate the amount of ecological water demand in the whole region,and provides scientific basis to maintain the balance of supply and demand in regional water resources.(2)The ecological water demand in the Hanjiang River Basin ranges from 481?2567373(m3/a),and the ecological water demand is concentrated at 3000?6000(m3/a),accounting for 76.68%of the area.These rivers have the largest demand for water.They also need more ecological water way beyond other areas in Hanjiang.But in places adjacent to rivers and lakes,ecological water requirements are minimal.It is worth mentioning that the ecological water demand in the junction area of Jingmen County and Shaxiang County in the central part of the Hanjiang River is also large,because the river passes those areas,and their soil water content is high.The crops they planted there are mainly paddy crops,resulting in a large ecological demand in the region.(3)The ecological water demand in the Hanjiang River Basin is highly satisfied,and the basic satisfaction is above 100%,that means that the water resources in the Hanjiang River Basin can meet the ecological water demand of the Hanjiang River Basin.Among them,the ecological water demand in the southeastern part of the Hanjiang River Basin is the highest,followed by the Northwest.The terrain in the central region is complex,the types of land use are diverse,and the degree of satisfaction is also large.The ecological water demand in the river areas is highly satisfied.The ecological water demand in the junction areas of Jingmen County and Shaxiang County in the Han River Basin is low.(4)The ecological water demand model is combined with geographic information technology to visualize the ecological water demand of the region.For the regions with too much or too little ecological water demand,we can understand the phenomenon and judge reasonable to formulate a policy.As the water source area of the middle line of the South-to-North Water Transfer Project,the Hanjiang River Basin is great significance,so the study of ecological water demand is particularly important.In particular,ecological construction has been emphasized many times,emphasizing the conservation and efficient use of natural resources since the 18th National Congress of the Communist Party of China.The ecological water demand model may play a important role in realizing the rational use of water resources and coordinating regional economic development.