Drought Risk Assessment of Agricultural Water Resources Supply-demand System

With the increasing shortage of agricultural water use, it is necessary to advance scientific indicators and model to assess the drought risk of agricultural water resources supply- demand system (or AWSSS). According to disaster theory, drought risk of AWSSS can be assessed through the fatalness of disaster-causing factors, the danger of disaster-forming environment and the frangibility of disaster-bearing substance, which are expressed by water supply shortage index, drought intensity index and output reduction index of crop respectively. To overcome the problem of information overlap among the three indicators and to scientifically evaluate the AWSSS, the Bucket theory is adopted to found assessment model. The drought risk is divided into five grades: lower risk, low risk, middling risk, high risk and higher risk. The above method is applied to Beixingjia Irrigation District, where the probability of drought risk exceeding low risk is 90%.