Ecological And Economic Analysis Of Ground Surface Response To The Lower Reaches Of The Tarim River After Ecological Water Conveyances

Tarim Basin is located in the arid desert region of deep inland, the ecosystem isextremely fragile. Since the1950s, the up and middle reaches of the waterconsumption of Tarim River had been increased, and the water drastically reducedreach to the downstream, because of the origins of the area of large-scale land andwater development. Especially the construction of Daxihaizi reservoir, lead to the357km river drying up of reservoir downstream for a long time, resulting in thewater tables are falling of the main stream downstream riverside, vegetation had lossof the survival conditions and gone to decline and degradation, desertified land wasexpanding, regional ecological environment was severely degraded, the "greencorridor" of downstream was in danger of disappearing. In order to save theecological environment in the lower reaches of the Tarim River, as a fundamentalpurpose that to protect ecological restoration and environmental, the National hasimplemented a engineering of Tarim River ecological water transporting from2000.During these years, nearly22.69×108m3ecological water has been successfullydelivered to the lower reaches of the Tarim River. There are a lot of positive responseand change to the lower reaches of the Tarim River ecological environment.The paper relies on the projection of the water conveyance of the lower reachesof Tarim River, mainly researches the ecological variation after water conveyance tothe lower reaches of Tarim River, discusses the variation of the groundwater level,biodiversity of the stand vegetation and physics and ecology of natural vegetation,analyses model that variation of the shrub biomass related to the variation of thegroundwater level, quantifies the value of the ecological variation effect after waterconveyance in the lower reaches of Tarim River using the new method of theecological economics. The research realizes innovation of the ecological variationquantificational analyses to the response of the serious damaged ecological system tothe large scale ecological project.Through researches, the paper obtains primarily conclusion as followings:(1) the groundwater level lifts at certain section in the lower reaches of TarimRive through large scale water conveyance by enforcing the project of the translatedwater, the condition of the degraded ecological system is obviously restrained as thegroundwater level lifts, the natural vegetation represents obvious response, mainlyembodying the mend of the growth condition and the variation of the biodiversity.(2) The general representation of the natural vegetation after water conveyance isthat：Obvious variation of the arbor, shrub and grass appears at the certain area alongriver bank, mainly embodying the variation of the growth and species, but if theresearch area is considered as the total lower reaches, the general trend of thevegetation degradation is not changed, the degradation of the vegetation community and the desertification of the land continue far from the river bank. So the researchscale must be confined certain area when we study the effect of the water conveyance.(3)Through analyzing, the groundwater level dynamics of the space and the timeare different, but there is obvious agreement between the response of the naturalvegetation and the groundwater level variation in space-time, in view of thegroundwater level lifting is not termination as end of the water conveyance at the sitewith long distance from the river, the response of the vegetation to the water level is along process, therefore we make sure that the vegetation restoration also is a longprocess in lower reaches of the Tarim river.(4) Based on willingness to pay that we have done the biodiversity valuation forthe lower reaches of the Tarim River, get the data of local residents annuallywillingness to pay from Daxihaizi Reservoir in the lower reaches of the Tarim Riverto Taitema Lake.74.25%of the survey is willing to pay money for the protection andmaintenance of downstream biodiversity, the median data is104.14Yuan one personper year.16%of the respondents wish to use the labor to substitute money by100Yuan/m. Select the34groups,35groups and total number of the local households’herders as the derivation the total sample, draw the bio-diversity of the region’snon-use value is460.46×10~4Yuan per year.(5) Take the section of Kaogan as an example, the result of the evaluation value ofthe ecological economics of the ecological variation effect after water conveyanceshows that: the value of the vegetation restoration in the lower reaches of the Tarimriver is0.65×10~4Yuan; the potential value of the groundwater level lifting by themathematics method is3.22×10~4yuan. The total input-output ratio is1:4.954. So thelower reaches of the Tarim River diversion project of the benefits are significant.