Quantitative Analysis Of Hydrological Characteristics Of Kaidu River Basin Based On GIS Technology

Kaidu River is one of four origins of the Tarim River, the longest inland riverin China. It’s also the main origins of the Bosten Lake which is the largest inlandfreshwater lake in China. The runoff changes of Kaidu River is important to the regionaleconomic development as well as the ecological environment improvement of Yanqibasin and the Peacock River basin.Owing to climate change and the influence of human activities, the fragile ecologicenvironment of Kaidu River basin becoming more and more serious in recent years,such as shrinkage of glaciers in upper reaches of the mountain, rivers drying up. Due tothe imbalance of water resource allocation in watershed, the demand-supply conflictbecame increasingly serious. The influence of overgrazing on soil erosion of grasslandbecame intensified in upper reaches. Secondary salinification of soil and groundwaterlevel forced upwards because of the sedimentation in the lower reaches of the river. Toanalyze the hydrological characteristics of this drainage basin are not only the basis forwater cycle and soil erosion’s research, but also can provides beneficial supports toavoid geological and flood hazard.This research extracted the river network, drainage divide, sub-basins of upperreach of Kaidu River and calculated the drainage area and river length of eachsub-basins using Geographic Information System (GIS) technology from digitalevaluation model (DEM) with30m resolution. Then, the drainage density, main-streamchannel longitudinal profiles and stream fractal dimension of the whole basin and sub-basins were analyzed and compared quantitatively. After made a detailed study ofthe geometrical hydrology characteristics which have been mentioned above, I analyzedthe fluctuation and seasonal change of the precipitation and discharge of Kaidu River bycorrelatively analyzing and linear regressing, and the precipitation and runoff data wererespectively observed in Dashankou hydrological station and Bayanbuluk meteorologystations. Further more, this study acquired the area rainfall of the basin based on the3scattered stations’ precipitation from1982to1987. Finally, the runoff coefficients ofwhole Kaidu River basin and the sub-basins were calculated with the area rainfall dataand runoff data observed in3hydrological station of upper Kaidu River area. Theresults show that:Firstly, the drainage density of the study area is0.208km/km2, the drainage densityof the watershed above Bayanbuluk meteorology stations is0.196km/km2, and the2hydrogeological units’(the watershed above Shanhentuhai hydrological station and thewatershed above Dashankou hydrological station)drainage densities are0.235km/km2and0.174km/km2.Secondly, the length of Kaidu River from beginning to Dashankou hydrologicalstation is367.6km, By analyzing the fractal dimension of river network and the mostproper fitting function of main stream profile, I speculate that the landform evolution ofthe study area has developed into early mature stage.Thirdly, the mean annual runoff of upper reach of Kaidu River is3.487billion m3from1956to2009, equivalent to runoff depth of183.29mm. There’s a clear low andhigh flow periods in runoff of Kaidu River. The ratio of runoff between low and highflow periods is2.03.The rainfall of the study area declines69.4mm with the elevationdrop100m.Forth, the mean annual runoff coefficient of the whole drainage basin is0.46from1982to1987, the watershed above Bayanbuluk meteorology stations is0.17. Therelative variation trend of flow coefficient turns to be stable.