Impact Assessment Of Water Resources Exploitation And Utilization On Ecological Water Use In Arid Area

Water resources are key restricting factor for social and economicdevelopment, and ecology and environment protection in arid area. In recentyears, with the rapid increase of economy and population in arid area, theamount of water demand and the level of water resources exploitation andutilization are increasing constantly, which leads to severe ecology andenvironment deterioration in arid area. Therefore, it has became a key issue inthe research of ecological water use in China and abroad how to evaluate theimpact of water resources exploitation and utilization on ecological water usein arid area. Taking a typical arid area in Northwest China as the studyingarea, this paper analyses the characteristics and evaluation standards ofdifferent types of ecological water use, and uses analytical hierarchy process(AHP) to evaluate the impact of water resources exploitation and utilizationon ecological water use in the studying area. Based on the evaluation results,some advices are put forward on the reasonable exploitation and utilization ofwater resources and the protection of ecology in the studying area.There are several types of ecological water use in arid area, includingecological water use of river ecosystem, floodplain forest, wetland and lakes,etc. Considering the actual situation in the studying area, the characteristics ofdifferent types of ecological water use are analyzed, and the evaluationstandards are proposed. For the ecological flow of the river, the evaluationstandard including five flow levels according to the Tennant method. For thefloodplain forest, groundwater level of river valley is used as an indicator todescribe the impact of water resources exploitation and utilization. If thegroundwater level drops, the growth of floodplain forest becomes worse. Andif it rises, the growth of floodplain forest improves. The ecological water useof the wetland is supplied by the river, so water level of the river is adopted asan index of the ecological water use of the wetland.AHP is a kind of multi-objective synthesis evaluation method combiningqualitative analysis and quantitative analysis. In this paper, the author uses AHP in the assessment of the impact of water resources exploitation andutilization on ecological water use in the main stream and tributary B of thestudying area. The results indicate that water transfer project from the mainstream to other regions brings serious influence to the ecological condition ofthe main stream, while the ecological condition of the main stream improvesafter adopting water transfer project from tributary B to the main stream.However, it has negative influence to the ecological condition of tributary Bto some extent.On this basis, the author evaluates the impact of the water transferprojects on ecological water use in the whole studying area. According to theresults, although the ecological condition will become worse in the future, itcan still maintain a certain level of the ecological water use. Therefore, weshould adjust the water resources quantity in water transfer projects andstrengthen water resources scheduling in the future, so as to protect theecology of the studying area. The results are useful for water resourcesmanagement and ecological environment protection.