| According to the report from the UNDP (United Nations Development Programme) in 2007, under the background of global climate change and competition for using water, the world is facing an enormous challenge to meet the increasing demands of the grain productivity having shortage of water resource. It is well-known that water crisis has been affecting greatly the human development. China owns a very large percentage of world's population. The social and economic stability of the nation even the world depends on whether the food security is guaranteed. Therefore, the restriction of water resource to the grain production has attracted worldwide attention, and it has important theoretic and realistic meaning to research on it.The total volume of food demand in a river basin can be got when a grain ration is provided. According to the water requirement and absorbed rain of the crops taking account of the irrigation loss, the volume of water for irrigation can be calculated in which the minimum value is the safety threshold. In this paper, the system of safety evaluation and the model of multi-effect evaluation for water resource are both constructed. In addition, Hai River Basin as a case study, some strategies for constructing the system of ensuring water resource security are provided. The major results are followings:(1) The system of safety evaluation for grain production is constructed. It is defined mainly from three aspects of water resource, including its volume, supply, and demand. And based on the system, combination with the analysis measurement of safety threshold, the safety of water resource of grain production is appraised, including demand and supply.(2)Promote a research method of safety threshold. This paper begins with the food criteria. Then the safety threshold of water resource for grain production can be got through combining the food demand and the water demand of grain production. At last, compare the safety threshold and the actual volume of water use and analyze the results.(3) The safety of water resource of grain production in Hai River Basin is appraised. Evaluation results show that Hai River Basin is under enormous pressure to the huge demands of water resource having the shortage of water. The grain production is hence restricted by the shortage of water resource. Nowadays, the grain self-sufficient rate is only 84% in Hai River Basin, that is, the water resource for grain production only meets 84% of the total volume and we can get supplement by exploiting other water resource and through food trade.(4) Some suggests are provided for constructing the system of ensuring water resource security. The system is considered from 4 aspects for water resource (e.g. developing potential, improving utilization efficiency, enhancing invest, and optimizing management), we should not only "open source", but also "save output". Based on the guidance of the scientific concept of development, it is necessary to utilize any water resource available, and constantly improve utilization efficiency of water resource to guarantee the food security, as far as possible to meet the water resource demands of other domains.In this paper, we try to do some innovation as follows:(1) Constructing the system of safety evaluation and introducing AHP (Analytical Hierarchy Process) and Delphi Techniques giving every indicator corresponding weight into the model of safety evaluation.(2) Promote a research method of safety threshold. Combine the food-grain-water demand of grain production to a system and analyze it. Then a total demand value of water resource, which is the safety threshold, can be got. Compare the demand value and the actual value of use in a river basin, we can get a realistic value of prediction of the grain self-sufficient rate in a river basin. |
