GIS-based Study On The Rainwater Utilization In Hilly Small Watershed

China is a country lack of water resource, the per capita water resources is less than1/4of the world’s average level.And the spatial and temporal distribution of water resources is unbalanced. With the development of China’s economics and society, water scarcity is becoming increasingly apparent. Rainwater is one of the most fundamental, direct, and economical resources. Development and utilization of rainwater resources have attracted our government’s attention. For small watershed in the hills and mountains, the rain water resources is the main source of regional water resourcesand the even the only source. Development and utilization of regional rainwater resources has become a fundamental way to resolve regional water shortages.This article describes the related concept and connotation of rainwater utilization and related concept of GIS. GIS is introduced in the research field of rainwater utilization for the purpose of trying to establish a regional rainwater utilization model. On the basis of analysis of the regional rainwater resource potential, the balance of water supply and demand and the factors that affect the pattern of rainwater utilization, various factors have been analysed to determine the regional rainwater utilization, rainwater use the size and location, ultimately establish rainwater utilization model and generate thematic maps by the use of GIS in the graphical representation of spatial data and attribute data space analysis.Taking Yizheng City, Jiangsu Province zaolin Bay Ecological Park as the study object, regional rainwater resources potential supply and demand situation in different levels were analysed and calculated. The region hydrological system was extracted by the use of arcGIS hydrological analysis module. Precise topographic factors, soil, vegetation and land use were analyzed to determine the rainwater use pattern in different regions, the size and location,thereby establishing rainwater utilization model. And finally for proving the rationality of the model, the model was analysed and evaluated.