Study On Urban Water Environmental Carrying Capacity

Water environmental carrying capacity is an important part of the environmental carrying capacity and an indispensable tache in sustainable development procedure of a country or an area. However, it is also the bottleneck that limits the development of human being in water shortage area. With the growth of population and the development of industry, the waste water increases and water pollution aggravates. The increase of ecological used water intensifies the conflict of demand and supply. If ecological used water is not enough, water pollution will aggravate during eco-city construction. Therefore, studying on urban water environmental carrying capacity is of great significance to promote sustainable development in northwest cities. This study takes Baoji city as an example to research on urban water environmental carrying capacity. It is of great importance to ecological gardens city construction in Baoji city. The main achievements were as follows:(1) Theory of urban water environmental carrying capacity was discussed in detail in this study. Urban water environmental carrying capacity was defined and its connotation, characteristics and quantization method was discussed. According to the concrete condition of Baoji city, evaluating indicator system, composed of one objective hierarchy, one criterion hierarchy and one index hierarchy, was established and analytic hierarchy process was adopted to evaluate the weight by the virtue of its important level to higher layer.(2) Based on the theoretical research on urban ecological environment water requirement, Baoji ecological environment water requirement was divided into two parts, one was greenbelt water requirement, and the other was river and lake water requirement. Baoji urban ecological environment water requirement was predicted. Meanwhile, in view of the important effect to Baoji city, ecological environment water requirement of Weihe River in Baoji section was predicted. The results showed that in the condition of current situation of pollution discharge, multi-year average ecological environment water requirement of Weihe River was 8.57×108m3, which was less than multi-year average runoff.(3) Based on the typical complicated system characteristics of water environment in Baoji, system dynamics (SD) model was used to simulate the water environmental carrying capacityin this paper. According to systematic theory and cause-effect analysis of the complicated system, SD model of water environmental carrying capacity was established and was divided into 5 sub-systems, including water resources, water environment, industry, agriculture and population. After the test of effectiveness and sensitivity, 12 different schemes were supposed. On the ground of the emulation of every scheme, its WECC was worked out respectively. The results showed that there was a degressive trend of Baoji WECC in the current condition. Any single measure could enhance the WECC, the effect was different, however. The comprehensive scheme, including water saving, pollution treatment, water source developing and water diversion, was the optimum project and through wich the WECC of Baoji could be improved most noticeably, almost by 110%, comparing with currnent sratus, and its WECC increased year by year.(4) Finally, operable and specific measures to advance the WECC of Baoji were put forward, aiming at optimum program.