| Hanjiang river is the largest tributary of the Yangtze river, is rich in water resources distribution, which accounts for7.2%of the amount of the latter. The Hanjiang river water resources development is the inevitable choice for sustainable economic and social development of the Yangtze River. And it is also the current economic and social development of the watershed province’s necessary. However, its rapid pace has leading to many environmental problems recently. Now, many environmental issues become increasingly prominent, while affecting the sustainable social and economic development. So, study on the influence on the water ecoenvironment and the ecosystem health assessment in the large scale of Hanjiang river basin by water resources development and utilization will provide technical support and scientific basis for watershed resources management and protection. In this thesis, we take Hanjiang river basin as an example, analysis the water resources carrying capacity, water environment carrying capacity and water ecological carrying capacity, and analysis the impact of ecological environment changes by hydropower cascade development and the impact factor of water blooms, and analysis the Hanjiang river basin ecosystem health.The main contents and conclusions are included in the following:(1) The distance-based index of Hanjiang river basin water resources carrying capacity conceptual model was constructed. In the basis of the evaluation index system, we established the index weight by using AHP. The grade upper, middle, downstream and the whole stream status of Hanjiang river basin water resources carrying capacity is:whole-"medium", upper-"higer", middle-"medium" and down-"medium". From a regional perspective, the descending order is:Hanzhong, Ankang, Shiyan, Shangluo, Shennongjia are "higher", Yingcheng, Hanchuan, Nanyang, Wuhan, Tianmen, Qianjiang, Xiantao are "medium", Jingmen is "lower" and Xiangyang is "lowest". The development and utilization has affected the Hanjiang river’s water resources, especially in the middle and lower reaches, the Hanjiang river water resources carrying capacity decreased significantly compared to the upstream. Combined with GIS technology and a comprehensive analysis of water resources carrying capacity, the Hanjiang river basin water resources carrying capacity chart was integreated by the calculation result. In addition, the Hanjiang river watershed carrying capacity system dynamics model was established. The model predict integrated water resources carrying capacity from2010to2040under different scenarios, and we proposed optimal solutions including open source, water pollution control and other measures to improve the Hanjiang river basin water resources carrying capacity.(2) The Hanjiang river basin water environment carrying capacity evaluation index system was constructed, and the index weight was determined by using AHP. The grade upper, middle, downstream and the whole stream status of Hanjiang river basin water environment carrying capacity is:whole-"lower", upper-"medium" middle-"lower" and down-"lower". From a regional perspective, the descending order is:Shennongjia is "higer", Hanzhong, Shiyan, Shangluo, Ankang are "medium", Hanchuan, Jingmen, Nanyang, Yingcheng, Qianjiang, Xiantao, Tianmen are "lower", Xiangyang and Wuhan are "lowest". Combined with GIS technology and a comprehensive analysis of water environment carrying capacity, the Hanjiang river basin water environment carrying capacity chart was integreated by the calculation result. The development and utilization has affected the water environment carrying index, middle and lower reaches of Hanjiang river water environmental carrying capacity was significantly decreased. In addition, the Hanjiang river watershed environment carrying capacity system dynamics model was established. The model predict integrated water environment carrying capacity from2010to2040under different schemes, and we proposed optimaization adjustment scheme including construction of water diversion project, transformation of water supply pipe network and construction of sewage treatment plants to improve the Hanjiang river basin water resources developpment and utilization.(3) On the basis of analysis of Hanjiang river hydropower cascade development, the thesis build a framework based on PSR model of cascade hydropower development of multi-level evaluation index system of ecological environment impact assessment. The result results showed that the Hanjiang river ecological environment impact assessment index rendered as an overall downward trend, hydropower cascade development will cause an "adverse" effect to the Hanjiang river watershed ecological environment. The hydropower cascade development and environmental pressures on the Hanjiang river ecological impact is more obvious, and the Hanjiang river ecological environment is showing a downward trend at the Wangfuzhou and Huangjinxia station’s operation. After the power plant operators in Cuijiaying, the ecosystem function will be improved as flood control and water regulation function increases, but with the the dam increasing it will have a decline trend. By using SPSS analysis the normalized hydropower development in the various stages of the pressure index and the Hanjiang river ecological environment impact assessment index, an impact prediction model was built to quantitative predict the Hanjiang river hydropower cascade development of eco-environmental impact.(4) On analyzing the causes of Hanjiang river basin water blooms, the conclusion is that the Hanjiang river water blooms were mainly affected by meteorological, hydrological, water quality and social economic factors influence. According to the restrictive conditions of Hanjiang river water blooms, using the principal component analysis screening significant influence factors, multivariate linear regression analysis method is adopted to establish multiple linear regression equation of the Xiantao and Wuhan section to further determine the main factors affecting the blooms occurred. Based on the response surface analysis, the linear regression model of Xiantao and Wuhan section of water bloom was established to quantitatively analysis the restrictions. In addition, the Hanjiang river basin system dynamics model was established, the temperature, flow, flow rate, total nitrogen, phosphorus and COD emissions were taken as a decision variable. The simulation results are obtained from the changing decision variables under different scenarios. Then the simulation results can be obtained to quantify the number of cells of algae under different scenarios. The results showed that the probability of water bloom declined and in2040was a significant downward trend after the implementation of transfer water from the mainstream (tributary) of Yangtze river to Hanjiang river and the joint scheduling of Danjiangkou reservoir and the transfer project, increasing pollution prevention efforts, implementation of ecological compensation and the protection of wetlands.(5) The Hanjiang river basin water ecological carrying capacity evaluation index system was constructed, with the analytic hierarchy process to determine weight. The grade upper, middle, downstream and the whole stream status of Hanjiang river basin water ecological carrying capacity is:whole-"medium", upper-"medium", middle-"lower" and down-"lower". From a regional perspective, the descending order is:Ankang is "higer", Shiyan, Hanzhong, Shennongjia, Shangluo, Qianjiang are "medium", Wuhan, Jingmen, Xiantao, Nanyang, Hanchuan, Yingcheng, Xiangyang and Tianmen are "lower". Combined with GIS technology and a comprehensive analysis of water ecological carrying capacity, the Hanjiang river basin water ecological carrying capacity chart was integreated by the calculation result. The development and utilization has affected the water ecological carrying index, the middle and lower reaches were significantly decreased. In addition, after building the Hanjiang river watershed ecological carrying capacity dynamics model and forecasting the change values from2010to2040under different schemes.(6) The watershed ecosystem health evaluation index system was constructed with the comprehensive health index method. The grade upper, middle, downstream and the whole stream status of Hanjiang river basin water ecosystem health is: whole-"unhealthy", upper-"sub-health", middle-"unhealthy" and down-"unhealthy" From a regional perspective, the descending order is:Hanzhong, Shennongjia, Ankang and Shiyan are "health", Shangluo, Jingmen are "sub-health", Nanyang, Hanchuan, Yingcheng, Qianjiang, Xiantao, Tianmen, Xiangyang and Wuhan are "unhealthy". It descripted that water resources development and utilization on the Hanjiang river watershed ecosystems are affected, especially in middle and lower reaches which ecosystem health levels is decreased significantly. Combined with GIS technology and a comprehensive analysis of water ecosystem health distribution, the Hanjiang river basin water ecosystem health chart was integreated by the calculation result. In addition, after building the Hanjiang river watershed ecosystem health dynamics model and forecasting the change values from2010to2040under different schemes, we proposed optimaization adjustment scheme to improve the Hanjiang river basin water resources development and utilization. |
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