Research On Ecological Effects Of Large-scale Reservoir

The ecological effect of hydraulic engineering, which is a new concept which has been advanced in recent years, refers to integrated outcome of both the ecological damage and recovery of the nature after the construction of hydraulic engineering. The ecological effect analysis on hydraulic engineering provides scientific base for whether the hydraulic engineering should be preserved, removed or improved according to the analysis about the effects of the hydraulic engineering on the living environment, the wild animals as well as plants, the natural regularity, and the economic growth. Although it is not completely equal to the environmental impact evaluation, the ecological effect analysis is the scientific base of environmental impact evaluation, which is mainly based on the river continuous theory, the flood pulse theory, and river ecological health theory.In the macroscopical perspective the ecological effect of all the hydraulic engineering has regularity to some extent. Combined with practical engineering, the ecological effect features of large hydraulic engineering has been analyzed and summarized on the whole.The ecological effect evaluation of large reservoir projects usually includes the survey on present condition of the ecological effect, the area division of the ecological functions, the construction of the ecological evaluation index system, the building of the ecological evaluation teaching model, and so on. And the survey on present condition of the ecological effect consists of the survey on both the natural circumstance and economic condition. According to the current state and the planning of the water resource development and utilize, the water domain can be divided into two-stage system. What's more, the ecological evaluation index system has been established based on analytic hierarchy process. According to the river ecosystem health theory, this paper mainly takes the river ecological water requirement into consideration. Based on the summary of domestic and foreign researches on ecological and environmental water requirement, this paper distinguishes the difference between the broad and narrow ecological water requirement, the difference between ecological water requirement and used water, and the difference between the ecological and environmental water requirement. What's more, the theoretical basis of ecological water requirement research is analyzed from the perspective of ecology and hydrology, and the research on ecological water requirement should be guided by the holism theory, species diversity theory, Shelford theory, dissipative structure theory, river corridor theory of landscape ecology and the hydrological cycle and water resources carrying capacity theory. And the theoretical basis of ecological water requirement research has an important guiding significance in reasonably defining the time scale, the space scale and protective target of the research.This paper analyses the relationship between economic and ecological used water, as well as natural and human factors that affect ecological used water, and designs conceptual model that ecological used water is influenced by ecological thought and management framework in social system, change of underlying surface, diversion and discharge in economic system, and the structure of ecological system and environmental elements in natural system. And based on this, an evaluation index using ecological water requirement as a ratio is put forward.The problem of the ecological effects in Baishi reservoir area is mainly attributed to the excessive groundwater level which is caused by the water storage in the reservoir area. In this dissertation, the let-down flow of Baishi Reservoir has been calculated by utilizing the coupling model of surface water and underground water. The theory that the minimum of let-down ecological flow of the reservoir needs to be designed is advanced through researching the tidal water requirement that is needed to maintain the health of estuary swamp with the aim to protect the lower strand and the estuary swamp. Because of the water requirement by the growth period of the creature, the let-down ecological flow has to be calculated at the monthly amount. From the perspective of the ecological health of the swamp and protecting the functional partition of the water resources, the idea of the ecological health of the estuary swamp and the protection of the functional target region has been put forward, and the ecological requirement for flow has also been advanced based on the analysis on the influences on the swamp ecology and the function of water resource of the changes in flow.The groundwater in the research area has been over exploitation for a long time, causing the aggravation of seawater invasion and the destruction of the original ecological balance. According to the data of detective concentration of Cl- and TDS in the groundwater, with the use of FEFLOW the model of groundwater solute movement is established, the law of the Cl- and TDS distribution is stimulated, and the ecological destruction of Daling and Xiaoling River Basin caused by seawater invasion is analyzed.Based on analysis and prediction of the balance of water resources supply and demand in Daling and Xiaoling River Basin, and according to the current situation that the western part of Liaoning Province lacks water, this paper proposes a scheme of inter-basin water transfer and construction of underground reservoir water supply project, and carries out a feasibility analysis. After the completion of the project, the need of production and living can be met to a large extent.