| At present, to research the ralation between human and nature on the basis of watershed as a unit, and to innovative and develop the theory and methods of watershed comprehensive management, which not only is the front field that urgent to capture,but also is the urgent request of country's economic construction.This study with a view the degradation status and law of several ecological indexes of NanHu watershed in Xinjiang Hami, explores the protection mechanism that suitable for Hami watershed, and provides a scientific basis for the large area of ecological protection projects .First of all.it is necessary to learn more about the situation on the ground, and gather comprehensive and representative information of NanHu through visiting Water Conservancy Bureau and statistical bureau in Hami.secondly , on the basis of analysis for information, there are surveys including field survey and interview survey which is oriented to management and resident personnel in NanHu.In addition, collection of samples for surface material (0-20mm)in Nanhu Lake is necessary.Finally, there is the indoor experiments and data analysis.In this paper,Taking research about watershed survey at home and abroad for research background, it is comprehensivethat analysis the water balance, biological changes and changes in the surface material on the basis of environmental profiles of NanHu. The first is reserching the water balance and change in lawsby analysis the access/exit surface runoff of NanHu Lake; then,thear is analysis about biological changes on the mainof analysis on vegetation and fish status. On experimental basis,this peper do the analysis about surface material particles in the horizontal and vertical distribution.Finally, Through the above analysis, the paper summed up the reasons and protection measures of watershed changes,specific conclusions are as follows:(1) In intraannual variation, NanHu water is the fullest in spring and the least in autumn; in annual variation, the water area of NanHu atrophyed from 8.9 km to 2.1 km in the past 49 years,and the annual average atrophy is 1.6%.(2) The vegetation of NanHu are relatively scarce in the amount and types,crops and economic forest area presented a rising trend,while the the number and the types of vegetation in lakeside declined,and the lakeside vegetation isto the direction of the spread of the lake.fish production down very quickly, and has the character as " two many and two little".(3) The particle size composition of surface material(0-20cm) in lakeside is mainly to the coarse silt,while the composition of colloidal particle,clay,medium sand and coarse sand is relatively small.In the level of distribution,the particle size was gradually thin and show an annular distribution from far to near lakeside,that is, coarse gravel and sand deposited in the far Lakefront,small silt, clay lakeside zone in recent sediment distribution, and it is in the direction of the lake gradually fine.(4) The reasons of environmental degradation of NanHu mainly is the anthropogenic causes,which includes overexploitation of underground water,large number of irrigation water consumption , reservoirs affected, the upper reaches of the closure serious, pesticide waste pollution,the irrational agricultural industrial structure, and so on.(5) The protection of NanHu watershed has extremely important significance.It is necessary to strengthen the protection of water quality, control of water,promote advanced water-saving irrigation techniques,and establish nature reserves in NanHu.and it is also importentto adjust the agricultural structure,formulate corresponding policies and regulations to protect the watershed environment. |
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