Study On The Optimum Allocation For River Basin Agriculture Water Resources Supported By 3S Technologies

Water resources is not only essentialy natural resources and strategicly economic resources, but also the most important factors of ecosystem environment.Following natural and economic regulation allocation water resources which can keep on population, resources and environment a sustainable development.It is premise that achieves optimum allocation of water resources in the life, the production and the ecosystem by taking river basin as a unit.Beijing is a severity water shortage city.The average of amount of water resources is 300 m~3 per person, much lower than 1000 m~3 limit of United Nations .In order to carry out the goal of"national capital city, international city, cultural city and proper reside city", Beijing have to sciencly resolve the problem on optimum allocationof water resources under the condition of absent water. The Chaobai River basin is the important water headwaters of Beijing, locating in the belts of east development on overall programming in Beijing city .The area of Chaobai River basin in Beijing is about 5521 square kilometers.There are Miyun reservoir, Huairou reservoir, eight factories water headwaters, and emergency headwaters field in the Chaobai River basin.It is the keystone of optimum allocation of water resources in the Chaobai River basin that reducing the agricultural water, raising the quality of ecosystem environment, guaranteeing the headwaters safety of the water supply.This research takes Chaobai River basin in BeijingCity as a research area. Firstly, according to natural geography characteristics in the region, the paper puts forward a comprehensive and automatic method on land classification in Chaobai River basin, and carries on land classification under presentcondition in Chaobai River basin by the satellite image of landsat TM (30 m×30 m) in 2005.Secondly, according to the theories of energy equilibrium adjacent ground, quoting from SEBAL1 model, making use of the diagram of NOAA satellite image and prognosticate weather data on the earth's surface to emend parameterof net radiation, soil hot flux and soil roughness degree etc,to confirm parameters model can adapt to Chaobai River basin, and compute evapotranspiration(ET) in 2005.Finally ,by investigating condition of input and produce at present plant condition, analyzing relationship between ET and rainfall to establish the index of sustainable development in Chaobai River basin. That is the economic factor is minimal imput and maximum output, and the ecosystem factor is maximum LAI, and the social factor is that plant ET is smaller than rainfall. Under current condition of land use ,which analysises optimal schemes to ecosystem, economy and society.It is innovation that the study put forward a 3S comprehensive automatic classification methd on the basis of remote sensing's automatic classification , the inquisition data, expert's knowledge,and history data, revise the SEBAL model parameter and apply in north China, confirm optimum allocation of water resources by linear programming.The theory combines with practice, which provide decision basis for comprehensive management in Chaobai River basin, for sciencly solving water allocation in life, produces, andecosystem . Which offer basis for adjusting planting construction and for monitoring and evaluating water resources.Which provide scientificinstruction for agricultural production and water resources management in Beijing city and north China plain.