Analysis And Research Of Regional Water Resources Carrying Capacity

Water resources is a kind of basic natural resources, one of the control factors of ecological environment, which is a strategic economic resources. It is an organic part of comprehensive national strength. Discussing national strategy of water resources for the 21^st and the related problems are the key issues cared by the whole world at present. Along with the deterioration of lacking of water, more and more attention is paid to local water resources currently, the tendency of development as well as the process of water exploring. The study on water resources carrying capacity is the result that people responses to continual water problems.On the basis of collecting related data, analyzing a lot of documents, the connotation and tendency of water resources carrying capacity are advanced in the paper. Meanwhile, it establishes an aggregative indicator system of assess on water resources carrying capacity. Then, using scenario analysis and integrated evaluate model of water resources, it evaluates water resources carrying capacity of Yan'an City. As an integrative indicator, water resources carrying capacity is calculated by comprehensive evaluation which is drawn on the weighted of the respective evaluations of the water resources sub-system, the ecosystem environment sub-system and the social economic sub-system, moreover, it reflectes the characteristic of many factors of water resources capacity composite system. The evaluation result of single sub-system is just one aspect of the factors. The conclusion can be educed as follows.(1) Water resources carrying capacity is the threshold that measures the water resources' restrictions on the social-economic develpoment, it usually uses some indicators to express, such as the population quantity and the economic scale that per capita water resources could afford when the demand and supply balance between the ecosystem avaiable water and the social-economic sustainable development demanding water is on the critical state.(2) In 2005, the index of water resources carrying capacity of Yan'an City is 0.4040, which can afford the development while the level is very low. In 2010, the index is 0.4602, which is still in the range of capacity, more than that of 2005. In 2020, the index is 0.5227, more than that of 2010, but still come to a preferable level of capacity. In a word, the water resources carrying capacity of Yan'an City is gradually improving, and the compound system develops well.(3) The evaluation index of water sub-system of Yan'an City is 0.3478 in 2005, in the lower level of capacity; the evaluation index of water is 0.2826 and 0.2500 in 2010 and 2020, beyond the capacity. This means that the water supply will be in a shortage, which will inhibit social development. The eco-environmental sub-system evaluation index is rising gradually. In 2005, it is 0.3803, in a lower capacity condition. It reaches 0.4859 in 2010 and 0.4983 in 2020, the capacity level is rising and eco-environment will be improved gradually. The social-economic sub-system evaluation index is 0.4546 in 2005, in a better capacity condition which indicates that the social-economic system develops well. The evaluation index of social-economic sub-system is 0.5376 and 0.6947 in 2010 and 2020 separately, which will be or has been in a better capacity condition. The results exhibit that the social-economic system will develop quickly during the next 20 years.