Environment Research And Conservation Of The Wetland Of Zhangye City

For the porpose of protecting the ecological environment of wetland, this dissertationtakes Zhangye Wetland for example, and selects the wetland of Zhangye City which is locatedin the Hei River basin reserve of arid areas of northwest China to research groundwaterenvironment. This dissertation points out the problems Zhangye city wetland is facing andanalyse the reasons. Combining the three elements of the wetland and the particularity ofZhangye wetland, the dissertation analise and evaluates the groundwater environment (waterquality, water quantity and groundwater antifouling property), soil environment and theecological geological environment; Considering that water is the key factor of wetland’sexistence and succession,the dissertation uses isotope method analyzing transformationrelation of the atmospheric precipitation, surface water, groundwater, soil water cycle in thestudy area and analyse the wetland water source;Using Visual Moldflow software forgroundwater flow numerical simulation for20years, predicting groundwater level trend in thestudy area;Finally puts forward some countermeasures to wetland protection andmanagement.Main achievements and conclusions are as follows:(1) The main problems which the wetland is facing is ecological degradation, waterpollution, soil salinization.The main reasons of wetlands degradation includes two types:natural factors and human factors. Natural factors are including the geological structure andclimate change for many years. Human factors are including wetland unreasonabledevelopment and utilization of water resources and land resources, agricultural reclamationand sewage discharge, etc.(2) This dissertation choose18indexes to evaluate the pollution status of study area,including total soluble solids, total hardness, total alkalinity,pH,Cl-,SO2-4,Mn,Cu,Zn,VolatilePhenol,NO--3,NO-2,NH4,As,Hg,Cd+6,Pd+2and total Fe. The exceed standard are total Fe, solublesolid, total hardness, plumbum, volatile phenol and nitrate. Through the comprehensiveevaluation pollution index, the study area is divided into the four partitions: pollutionseriously polluted area, moderate pollution area, slight pollution area and no pollution area.(3) By analyzing and calculating, the natural recharge of groundwater in study area is89226.24104m3/a, the sidely run-off is the main recharge of groundwater which is about71.83%. The output recharge is88011.87104m3/a, the proportion of the sidely run-off is21.06%, the spring spillage is about58.65%, the withdrawal is about14.71%, theevapotranspiration is about5.57%.(4) Based on the antifouling porperty DRASTIC index calculation results and the classification standard, the study area is divided into three antifouling porperty zone: betterantifouling porperty zone, medium antifouling porperty zone and poor groundwaterantifouling porperty zone.(5) According to the soil environment comprehensive index model, the study area can bedivided into four partitions: the best soil environment, better soil environment, medium soilenvironmental and poorer soil environment.(6) According to the ecological geological environment comprehensive evaluation indexand the quality grade standard, the study area is divided into three partition: good ecologicalgeological environment zone, medium ecological geological environment zone, poorecological geological environment zone.(7) On the basis of the testing data of constant environmental isotopes(2H、18O) ofatmospheric precipitation, surface water, soil water and groundwater of Zhangye city wetlandresearch area, it is concluded that the transforming relationship of water resource in studyareas. Moreover, using the Tritium isotope testing data compute groundwater-age, analyzingthe characteristics of environment isotopes of groundwater in the study area. It draws thetransforming relationship of water resource futher. Draw the conclusion that wetland watersource not only includes springs, but also includes surface water and groundwater which flowthrough the area. Investigate its supply source, more than64%soil water, spring water,shallow confined water, diving and surface water are from the infiltration of surface waterrunoff in the mountain eare.(8) Groundwater flow simulation of Visual MOLDFLOW concluds that groundwaterlever of northwest will increased slowly in the future, but the southeast will go down slowly.(9) Wetland protection and management, want to have a perfect wetland protection lawsand regulations, and increase investment in science and technology of wetland research, thereasonable use and deployment of wetland water resources, strengthening propaganda andeducation of the importance of wetlands, vigorously develop alternative industries, and reducethe current agricultural pollution of the wetland.The study provide the important scientific basis for wetland protection. At the same time,it provides theoretical support for the government and relevant departments to formulate thewetland protection and exploitation and utilization of water resources. It provides theoreticalbasis for protection and construction Zhangye ecological environment safety and the oasissustainable economic and social development.