Study On The Influence Of The Change Of Water Resources And Its Impact On Ecological Security In The Arid

Water resources are the key determinants of social and economic development and ecological environment protection in arid areas.Over the past 60 years,the Ebinur Lake Basin has developed a series of ecological security problems,such as intensified land desertification,declining vegetation and Ebinur lake drying mainly due to over exploitation of water resources.In this paper,the integrated use of meteorology,hydrology,management science theory,in consideration of climate change and human activities,using remote sensing and GIS technology,Eco-Hydrological monitoring,model simulation method,analyzed the change characteristics and regularity of surface runoff,oasis irrigation water and water intake of tail Lake;and ecological security problems of basin were analyzed,the estimation of ecological water requirement;finally put forward relevant countermeasures and suggestions of sustainable utilization of water resources about Ebinur Lake Basin.The main conclusions were as follows:(1)By using wavelet analysis,non parametric test and Hurst index method et al,runoff's multi-scale change of the hydrological of Jinhe Shankou,Bole,and wenquan were analysed during 1960-2015 years.The research shows that the annual runoff of Jinghe Shankou hydrological Station is decreasing generally,and there is a main period of 30 years.The annual runoff of WenQuan and Bole hydrological Station generally has an increasing trend,and all of them are mutated in 1997,the main periods are 28 and 32 years,respectively.The runoff of Jinghe Shankou hydrological Station and WenQuan hydrological Station are mainly concentrated in 6-8 months of the year,while Bole hydrological Station is concentrated from November to Coming year's March.(2)The temperature,precipitation and actual evaporation of the Ebinur Lake Basin increased significantly,but the potential evapotranspiration was decreasing during 1960-2015 years.The climate sensitivity method was used to quantify the contribution rate of climate change and human activity to the effect of runoff.Among them,in Jinghe Shankou,WenQuan and Bole hydrological station,the runoff change caused by climate change contribution were 46.87%,58.94%and 51.10%,The contribution rates of human activities were 53.13%,41.06%and 48.90%,respectively.(3)The CMADS data set combined with the SWAT model was used to simulate the runoff in the upper reaches of the basin.Based on monthly scale,the NSE efficiency coefficient of the WenQuan and Jinghe Shankou hydrological station are0.79 and 0.87,respectively,and the NSE efficiency coefficients in the validation period are 0.71 and 0.82,respectively.Based on day scale,the NSE efficiency coefficients of the two hydrological stations are between 0.69-0.77,The results show that the SWAT model meets the accuracy requirement of watershed runoff simulation.For this purpose,8 climate scenarios and 3 land use change models were set up to simulate runoff changes.the simulation results show that the temperature and precipitation increase positive runoff increased significantly,and vice versa;reduce the increase of arable land and water area will greatly reduce runoff,reduce the grass,woodland and shrub forest area will be the runoff in flood season is more concentrated.(4)In 1960-2015 years,the amount of water diversion in the irrigation area has been increasing,the exploitation of groundwater is increasing gradually,and the proportion of agricultural water is always above 95%of the total water consumption.Among them,grain crops and cotton are the largest water consumption items.The proportion of water use in industry,living and ecological environment is small,not more than 1.00×10~8m~3 for years.(5)In 1989-2015 years,The total annual water of four entry lakes(82 farm,90farm,five branch and total row station)in Hukou overall present the tendency to decrease in general fluctuation.From the mountain into Hukou,uneven distribution of runoff becomes larger.Water of 82 farm Station mainly concentrated in 6-8 months,but 90 farm Station concentrated on November.Because of the agricultural irrigation water continues to increase,which lead to flow into the lake in summer reduce a lot than in winter,such as the total row and five branch station in June to October years of the occurrence of drying part,no water entering Ebinur Lake,which leading to serious atrophy of Lake area.(6)The change of water resources in Ebinur Lake Basin has produced a series of ecological safety problems,mainly as follows:terminal lake Dry shrinkage,desertification,vegetation degradation,terminal lake hukou disconnection,decline of groundwater level and water quality deterioration.The modified Constanza model were used to evaluate the ecological service value(ESV)of the whole basin for1990-2015 years,and the ecological service value of the whole basin were greatly reduced,and the whole basin ecological service value decrease 65930.47*10~4 yuan.Which showed that the ecological environment of the whole basin have undergone significant degradation.(7)The ecological water demand type of Ebinur Lake Basin can be divided into:natural vegetation,terminal lake,Channel/canal system and artificial vegetation,using related methods of the ecological water demand of whole basin were estimated.Among them,ecological water demand of natural vegetation is 4.82×10~8-5.01×10~8m~3,ecological water demand of terminal lake is 3.98×10~8-4.39×10~8m~3,ecological water demand of Channel and canal system is 0.75×10~8-3.22×10~8m~3 and ecological water demand of artificial vegetation is 0.51×10~8m~3,the total ecological water demand amount to 10.06×10~8-13.13×10~8m~3.(8)In order to realize the sustainable utilization of water resources in the Ebinur Lake Basin,We put forward the following suggestions:strictly implement the"three red lines"and the relevant countermeasures and suggestions,such as reducing land and water,rationally distributing water volume and water rights,and developing water resources.The study Expects deepening the understanding of the response of water resources to climate change in arid.Strengthening the study of ecosystem pattern and process evolution in arid,And the research results would provide typical case for the study of basin management in the whole arid.