The Spatial Evaluating Model For Water Resources Carrying Capacity And Its Application Research

With the rapid development of economy and the over expansion of population,the contradiction among water resources,water environment,population and development becomes increasingly acute.The spatial distribution of water resources and unreasonable structure of using water resources have caused a potential risk to the sustainable development of social economy in Kaidu-Kongqi river basin.Accordingly,the assessment of water resources carrying capacity would provide references to the planning of water resources in water-scarce areas.Meanwhile,it is also conducive for managers to deal with the current environment and economic development.In this paper,the basic statistical datas are used to establish a dynamic model of water resources carrying capacity by taking Kaidu-Kongqi river basin as example firstly.Secondly,3 schemes are designed by changing the decision variables of the model to simulate the spatial variation of gross water requirement and water resources supply-demand difference in 2010,2020 and 2030.Finally,the spatial distribution of water resources carrying capacity is calculated by entropy method.Through comparing the results of two analysis methods,some countermeasures are put forward to improve the water resources carrying capacity.The main conclusions of this study are as follows:(1)The dynamic model of water resources carrying capacity in Kaidu-Kongqi river basin is constructed based on the principle of system dynamics model and the function of geographic information system.After testing the validity of the model,we can draw the conclusion that the model is reasonable,the fitting accuracy of the historical data could meet the requirements and the model could preferably represented the actual operating characteristics of the system.(2)The results of the simulation used the space system dynamics method shows that the spatial distribution of water resources supply and demand is obviously uneven,and the results in the northern area is obviously higher than it in the southern area.Most of the difference between supply and demand in Hejing county are more than 45 billion m~3.Korla is the most serious water scarcity city with the difference between supply and demand of-9.648 billion m~3.On the whole,from 2010 to 2030,the difference of water supply and demand in the basin is increasing year by year,so the contradiction between supply and demand is also increasing.(3)Through the comparison and analysis of the water-saving scheme,adjusting industrical structure's scheme and the comprehensive scheme,some conclusions were analyzed: after adjusting the industrial structure scheme,the carrying capacity of river basin water resources was decreasing and the contradiction of water resources supply and demand is most prominent.The water resources carrying capacity of the basin has been improved,and the growth rate is only inferior to the comprehensive one after adopting water-saving scheme.Under the comprehensive scheme,the water resources carrying capacity of the Kaidu-Kongqi river basin is greater than that of any single factor.Therefore,the comprehensive scheme is the optimal development plan.(4)The calculation of entropy method shows that the water resources carrying capacity of each county in the Kaidu-Kongqui river basin is characterized by spatial and temporal differences,and the comprehensive level is low.The water resources carrying capacity index in 2020 was the lowest,and its value was 0.283.The index shows the maximum value of 0.392 in 2030.The index value is 0.364 in 2010,which was between the value of 2020 and 2030.Among them,the maximum value of water resources carrying capacity is 1.39 times of the minimum value.The reduction rate from 2010 to 2020 was about 22.3%,and the increase rate from 2020 to 2030 was about 38.5%.(5)To contrast the evaluation results of water resource carrying capacity of space system dynamics and entropy method,we found that although the principle of the two methods are different,the spatial distribution trends of the bearing capacity were similar,which could reflect the basin water resources carrying capacity.(6)Water resources carrying capacity is affected by water resources to a certain extent.In terms of the spatial perspective,the water resources carrying capacity of Hejing county is highest in the watershed,followed by Korla city,the lowest was Yuli county.The water resources carrying capacity in Hejing county is strong because of the abundant water resources.However,the average amount of water resources in Yuli County is only 0.1389 * 108 m~3,the water resources carrying capacity is also at a poor level.