Research On Ecological Operation Objectives Of Three Gorges Reservoir

The previous research results show that the change of flow situation is the main driving force in the evolution of the river ecosystems. The flow situation including the change of water depth, velocity, water temperature and significant river change of the hydrology, hydraulic conditions which was caused by reservoir regulation, have an important impact on river water quality, biological habitats and biomes.With the construction of Three Gorges Project on the Yangtze River, it is changed in the river runoff and its seasonal distribution and environmental factors which are related to the river runoff. These changes will indirectly or directly affect the water rest area and living habits for the important creature which is living in the Yangtze River and make biological community structure and composition distribution etc. changed, thus causing the great effect on the ecology and environment in certain area of the Yangtze River.By the extensive research about western and domestic theories and practice in the related field, on the basis of historical data and field investigation and further researching basic theory and methods of reservoir ecological operation, the paper focus on the investigation and analysis about the observation data of the Gezhouba and Three Gorges project's river water environment, hydrological changes, biological species changes between pre-and post. Besides, by the mathematical means to simulate complex physical phenomena, base on the computer numerical methods, the hydrological and hydrodynamic model of the Three Gorges Reservoir downstream is established which can simulate the evolutionary process about how the Three Gorges Reservoir Dam running impact on hydrological situation in the Yangtze River between pre-and pos.Based on the research how the Gezhouba running impact on the river hydrological regime, water environment and ecological changes, the paper researched the influence character about the running of Three Gorges project affecting the eco-hydrological conditions, the important biological natural reproduction in the reservoir downstream, an important habitat restoration, reconstruction of the hydraulic conditions and river ecological flow, analyzed action process and law about project scheduling-water situation-ecology environment.By the specific analysis effect of the Three Gorges Reservoir impacting on the river ecosystems and environmental flows in the downstream river channels, with the existing reservoir operation rules of the Three Gorges reservoir operation, the paper analyzed ecological objectives of Three Gorges reservoir operation and relevant compensation measures to ensure sustainable development of river health.With the comprehensive research proposal, research objectives and research content, and to combine the research status, the main conclusions of this paper include the following aspects:Firstly, it is done using of MIKE11 hydrodynamic model to build the Three Gorges Reservoir downstream of the one-dimensional hydrodynamic model. In accordance with the results of the model calibration analysis, the model which considers the major tributary of the Yangtze River has a high accuracy. The model by choosing the parameters can better reflect the topographic features, so the model is available. By the further simulation of the study area of the Three Gorges Dam between pre-and pos within a long series river runoff (1956-1985,2003--2008),it is simulated that the changes in hydrological regime, so it provides a scientific basis for reasonable and feasible to the next goal of ecological regulation.Secondly, according to the ecological assessment of river health indicators of hydrology hydrological regime of the Yangtze River. According to the daily river hydrological data, and IHA methods, extraction of the 32 eco-hydrological characteristics of the key significance, this 32 values of hydrological characteristics reflect the size of the flow, time of occurrence, frequency, duration and rate of change and other hydrological characteristics, can be better comprehensive analysis of the hydrological regime of the Three Gorges Dam on the downstream effects. Finally consolidated hydrological variability, and to assess the hydraulic impact on river ecology.Thirdly, used the PHABSIM model to simulate the Three Gorges Reservoir downstream river fish including sturgeon and Four major fish habitat,and thus the simulation of spawning habitat can use the relationship between area and flow with the best ecological flow. The results showed that:â‘ sturgeon spawning of appropriate environmental flows for the 8000-20000m3/s, the most appropriate environmental flow 12000m3/s.â‘¡Four major fish suitable spawning environment of the flow 8000-15000m3/s, the most appropriate environmental flow 11000m3/s.Finally, according the simulation results based on the numerical model with hydrological and physical habitat evaluation model to simulate the flow of best ecological habitats, considering the flood control, power generation, shipping and ecological benefits, come up with concrete and feasible ecological operation objectives and ecological compensation measures.