Researches On Impact Assessment Of Interbasin Transfer Projects On Terrestiral Environment

On research situation of environmental impact assessment of interbasin transfer projects at home and abroad, in the water-exporting area and intake area, the paper summarized influencing factors of interbasin transfer projects on entironment. Then the characteristics of uncertainty and complexity, evaluation theory and methods up-to-date were summarized.From terrestrial plants, the thesis made a summarization of influencing factors of interbasin transfer projects on terrestiral environment. A favorable effect of plants in the water-exporting area is microclimate of reservoirs on vegetation nearby. Unfavorable effects consist of six aspects. These effects are water reduce on agricultural vegetation along two banks of downstream water source area, occupied land on construction, construction activities, reservoir inundation, reservoir resettlements activities, and exotic plants interference on terrestrial plants. In intake area effects are favorable, including both agricultural vegetation and vegetation coverage.In the thesis, taking Hanjiang-to-Weihe River Project as my research object, it is studied effects of the project on terrestrial plants. The project crossed both the south and north slope of Qinling mountains. And the evaluation scope involves two climatic zones, with rich biodiversity. From the perspectives of flora, vegetation actuality, national key protected plants, and ancient and famous trees, the paper briefly introduced the situation of terrestrial plants. Then from four aspects of water source area, along the conveyance, downstream water source area, and intake area, combined with actual situation of the project, impacts on terrestrial plants were assessed.The total area of submerged and occupied cultivated land in Hanjiang-to-Weihe River Project is 96.59hm~2, occupied 0.0070% of evaluation scope (total area of 13734.92km~2). Huangjinxia reservoir and Qinling tunnel will submerge and occupy much more cultivated land. Huangjinxia reservoir will submerge 48hm of cultivated land, while Qinling tunnel will permanently occupy 26.05 hm~2, which will have much influence on basic farmland.Permanently-occupied forest area of the project is 989.74mu, while temporaryly-occupied forest area is 1828.28 mu. And the occupied forest area has a little natural forest. Despite of moderate exploitation, the project influence on natural forest should not be negligible.By productivity analysis, if the engineering construction is accomplished, production capacity in evaluation scope will reduce from present situation of 1095.47gC/(m~2.a) to 1095.40gC/(m~2.a). With verry a little reduce, the project construction influence on productivity of natural system will be endurable.The results show that submerged plants in water source area are all ubiquitous species, inundation will not cause species perdition, nor the flora properties in water source area. Plants lop on the immigrants construction, and production and life will lead to adverse effect on plant resources.Construction along the conveyance will take up some plant, but it will not influence species variety in the area. Such construction activities as excavation of tunnels and inclined shafts of work area, road construction, waste slagwill have certain influence on peripheral vegetation. No alien species has been found outdoors, but monitoring alien species on the process of construction should be paied attention to, in order to prevent their invasion. In evaluation scope no protected plants will be effected except Glycine Soja, which is at lower altitude. Sophora japonica in Chenjiaba town Foping county and Carya cathayensis in Xiaowangjian town Zhouzhi county, near the conveyance line, should be on-site conservation.Downstream water source area Hanjiang river will has reducing water, causing the water level in the lake to drop and function of water bodies impaired, thus resulting in agricultural irrigation difficult. The final result will be unnormal growth of agricultural vegetation.Agricultural vegetation in intake area, Central Shaanxi will obtain benefits. Water transfer will make a rise in water quantity, regulate microclimate, raise vegetation coverage, improve ecological environment in Central Shaanxi.Environmental impact assessment of interbasin transfer projects at home and abroad started very early, but nobody mad a systematical summary of environmental impact assessment. In my thesis, refercence to beneficial experience at home and abroad, it is the first one to summarize, complement and perfect influencing factors, evaluation theory and method of interbasin transfer projects on entironment. Otherwides, the project crosses two climatic zones, so it is a typicalinterbasin transfer project. And the research on it will enlightenment to the whole study field in future. Experience and shortage of the example will also have reference value to environmental impact assessment of entire water transfer projects.