Research On The Models And Their Application Of The Impact Of Hydropower Development On The Mountain River Ecosystem

The hydropower development can not only make full use of water resources, but also directly relate to the goals of national energy saving and emission reduction and the implementation of the sustainable development strategy. The programs of CPC Central Committee and State Council in the12th Five-Year Plan emphasize on reinforcing the protection of ecology, maintaining the carrying capacity of regional resources and environment and enhancing efforts on environmental protection and resource conservation and management. Therefore, it is a significantly practical problem that how to obtain the maximum economic benefits of cascade hydropower development and make an scientific and rational assessment of its impact on the river ecosystem at the same time to realize the coordination and sustainable development of the economy, society, resource and environment by conserving when exploiting, and exploiting on the basis of conservation.With abundant water resources and great potential for the development and utilization, China’s mountain rivers occupy a very important strategic position in the national water resources and hydropower resources allocation pattern. The mountain river hydropower development and its impact on the ecosystem are complicated and special. In this paper, Nujiang Basin is studied as an instance. And the impact of hydropower development on mountain river ecosystem are studied deeply by focusing on the basic theory of mountain river ecosystem, mountain river ecosystem health, sustainable development capacity of mountain river ecosystem, ecological carrying capacity, impact of hydropower development on the temperature of the river, water footprint of hydropower development etc. The main results are as follows:(1) Impact models and their application of hydropower development on mountain river ecosystem health and sustainable development capacity. In this part, firstly, the evaluation index systems of mountain river ecosystem health and sustainable development capacity are constructed by analyzing the basic characteristics of the mountain river and considering the natural ecological functions and service functions for human of mountain river ecosystem. Next, the mountain river ecosystem health impact model is established based on improved genetic algorithm and projection pursuit method. And the mountain river ecosystem sustainable development capacity impact model is established based on information entropy and technique for order preference by similarity to ideal solution. Last, these models are applied to the Nujiang ecosystem, which proves the rationality, feasibility, and practicability of the index systems and models. In this part, two conclusions are obtained. On the one hand, the proper hydropower development in Nujiang Basin can effectively improve the service functions for human of the mountain river ecological system and improve the unbalance between the river system and the mountain system, so that the whole mountain river ecosystem will be better and healthier. On the other hand, either hydropower development or tourism development can make sustainable development capacity of the Nujiang River ecosystem increase to some extents. And the increase of the former is greater than the latter. Besides, the collaborative development of hydropower and tourism in Nujiang area can make its infrastructure more complete and resident incomes higher.(2) Impact model and its application of the hydropower development on the ecological carrying capacity of the mountain river ecosystem. In the first place, according to the concept of ecological carrying capacity of the ecosystem health, impact evaluation index system of hydropower development on the regional ecological carrying capacity is constructed and the calculation model based on projection pursuit is established. Furthermore, taking Nujiang Basin as an example, the impact of hydropower development on the ecological carrying capacity is analyzed in depth. The best balance point between the maximized hydropower benefits and the minimized negative impact on environment is found to explore the conditions and modes of the coordinated development and mutual promotion of hydropower development and ecological environment. The research results show that Nujiang hydropower development has a positive impact on the regional ecological carrying capacity of Nujiang area with four cascade hydropower stations.(3) Impact model and its application of hydropower development on the temperature of the river. On the basis of M1KE11software, one-dimensional water temperature model and elevation two-dimensional water temperature model are established, which provide an effective way for the prediction of river water temperature. What’s more, taking Nujiang River as an example, the water temperature of natural river and the water temperature of reservoir and discharge with four cascade hydropower stations of Nujiang River are predicted to study the impact regularity of Nujiang hydropower project on river water temperature, the relationship between reservoirs form state and water temperature, and the cumulative effect of reservoir operation modes on water temperature. Besides, aiming at the cold-water-discharge issue, corresponding countermeasures are proposed, providing technical support for temperature control of Nujiang River under cascade hydropower stations operation.(4) Research on water footprint calculation of hydropower development. In this part, water footprint method is applied to evaluate the water consumption of mountain river cascade hydropower development. By assessing the water footprints of Nujiang River cascade hydropower stations, the quantitiy of the water consumption in the power generation process can be researched, which has an important reference value to Nujiang River cascade hydropower stations to be built and has important theoretical and practical significance to broaden the ideas and methods of evaluation of the use of water resources for hydropower development.