Study On Supergene Ecological Effect Excited By Groundwater And Its Evaluation

Northwest of China, whose area accounts for 38 percent of the total, is one of the typical arid and semi-arid zone in the world. There exists unique attribute such as short rainfall with uneven distribution on space-time , strong evaporation, vulnerable ecological environment and finite total water resources in the area. Therefore, production of industry, agriculture and livestock, human lives and ecological environment are dramatically depending on groundwater. However little emphasis has been placed on supergene ecological environment excited by groundwater and thus , the eco-value of groundwater has not embodied during conventional evaluation .development and exploitation of groundwater resources, which not only bring about a series of negative effects to ecological environment but also severely confine society and economy development and human living space in the area.Directed toward the supergene ecological effect excited by groundwater, the paper, for the purpose of maintaining sustainable exploitation on groundwater and ensuring coordinated development of ecological environment, theoretically attempts to define eco-value of groundwater and puts forth a theory and method to evaluate ecology-oriented regional groundwater resources, practically attempts to analyse supergene ecological effect excited by groundwater in Tuwei river drainage, which supports scientific evidence to exploit water resources rationally and protects ecological environment effectively, technically attempts to couple lumped parameter model distributed parameter model with ecological evaluation model to trace real-timely.Guided by these ideas mentioned above, we comprehensively generalized the present status of study on supergene ecological effect excited by groundwater and eco-value conception and then, based on relationship between groundwater and supergene eco-environment the concept of eco-value of groundwater is put forward and its intension and extension is analysed, which enrich the eco-value theory of water resources.Targeted by maintaining sustainable exploitation on groundwater and optimal circulation of eco-environment, guided by the system theory, based on geology and hydrogeology condition, the theory and method to evaluate ecology-oriented regional water resources is brought forward by means of coupling lumped parameter model, distributed parameter model, eco-environment evaluated model and GIS technique, which extended the theory of regional groundwater resources evaluation. Except for that, we developed Eco-environment Evaluation and Prewarning Information System based on MAPGIS, which, on the one hand supplies a visual and integral information platform and an evaluation tool for evaluating and prewarning on supergene ecological effect excited by groundwater, on the other hand realizes to integrate evaluation and prewarning and trace real-timely to eco-environment as well.Through field investigation about the relationship between groundwater and supergene ecological environment, based on analyzing characteristic of hydrologic cycle and ecological system in Tuwei river drainage, the relationship between depth of groundwater table and distribution of water and salt in aeration, between succession of plants and basic flux of the river are researched, succeedly the normal moisture content and salt content for representative plants such as salix mongolica and salix matsudana are determined, variant depth of groundwater table interval which including salinization depth of water table (<1m), optimum workable depth of water table(1~3m),arbor and bush bearable depth of water table(3~-5m), warning depth of water table(>8m) are set forth, which offer scientific evidence to rational exploitation on groundwater and effective eco-environment protection. At the same time, the factors that affect the supergene eco-environment are discussed, and the hierarchical evaluation index system, the evaluation standard and the evaluation method on supergene ecological effect excited by groundwater are formed.With fuzzy comprehensive evaluat...