Study On The Relationship Between Vegetation Ecology And Groundwater In The Golmud River Catchment

The Golmud River Basin is located in the south-central part of the Qaidam Basin in China,it is typical semi-arid watershed in the northwest region.It riches in mineral resources and geographical location,this plays an important role in supporting regional and national economic development.In the Golmud River Basin,the precipitation is scarce and the evaporation is intense,and the precipitation is mainly concentrated in the mountainous areas.It has little effect on the ecological evolution of the plains.So,the growth and development of the vegetation mainly depend on groundwater.Taking the Golmud River Basin as the research area,this paper takes the groundwater dynamics,hydrogeological basic theory,etc.as guidance,and uses field surveys,remote sensing interpretation,numerical simulation,and other technical means to carry out the research on the relationship between vegetation ecology and groundwater,obtained the following conclusions and understanding of:1.The overall vegetation coverage in the Golmud River Basin is relatively poor,and the differences in vegetation index between different landforms are relatively large.The interannual and inter-monthly changes of the vegetation index in the time distribution were not strong,and the overall trend showed a slight increase.The spatial distribution of vegetation mainly develops in the south-central part of the study area,and is distributed in bands on the east and west sides of Golmud City.2.The migration direction of the oasis gravity center in the Golmud River Basin is southeast-southeast-southwest-southeast.The oasis area increased for the first time in 2006.That is to say,the oasis has begun to develop toward the scope of scale expansion.The development of oasis has gradually become more balanced,and the increase and decrease of grassland area and forest land area have the greatest impact on the expansion and reduction of oasis.3.The ecology of different landforms in the Golmud River Basin is closely related to the depth of groundwater.In the marsh wet zone,when the depth is shallow,there are vegetation growth in each interval.The water depth is buried in the range of 1-2m,and the vegetation index can reach 0.8.That is to say,the vegetation growth is best in this buried depth zone.The continuous decline of water level,vegetation roots due to excessive water depth caused by lack of water,can not maintain its normal growth and death;salt marsh belt,the overall growth of vegetation is poor,vegetation coverage is low,and the vegetation index is not width the depth of groundwater.The increase will change.Thus,the threshold for the survival of vegetation-dependent groundwater in the Golmud River Basin was determined to be 0.4-3m.4.The change of groundwater exploitation in the Golmud River Basin has different influence on the vegetation.Under the current exploitation volume,when the groundwater decreased by lm,it had the largest impact on the area of Apocynum and loquat,accounting for 57.05%of the total area of the relied on groundwater vegetation(1770km2).Under the recent mining volume,when groundwater decreased by 3m,it had the greatest impact on the reed and Tamarix area.This accounted for 11.99%of the total area of the relied on groundwater vegetation(1770km2).Under the long-term mining volume,when groundwater decreased by 3m,it had the greatest impact on the reed and tamarix area,accounting for 15.04%of the total area of the dependent groundwater vegetation(1770km2).Therefore,in the rational development of groundwater,it is necessary to protect the vegetation that has been affected to varying degrees.Through the evaluation,the proposed extraction volume is 60�104 m3/d.The above research results have guiding significance for the rational development and utilization of water resources in the Golmud River Basina,nd can also provide reasonable suggestions for the protection of the ecological environment in the Northwest Inland Basin.