Analysis And Simulation Of Runoff In Hotan Catchment

As the only river that traverses the Taklimakan Desert, water resources in Hotan Catchment is the main source of Hotan oasis-Green Corridor in the Desert. Researches on runoff process are beneficial for the sustainable utilization of water resources, water conservancy planning and the development of agriculture. The paper is composed of three parts, analysis of runoff process, source area rainfall runoff simulation and flood channel routing in plain.Both intra-annual and inter-annual variation of runoff in the catchment has been analyzed in the paper. The results show that as glacial and snow melt is main source of runoff, the nonuniformity of intra-annual runoff is very high, the coefficient of nonuniformity and the degree of concentration are far bigger than normal, the computed time of concentration is in accordance with the occurrance of the observed maximum monthly runoff. The Kendall rank test had been used to analyze the trend of the runoff in the catchment, and the result shows a weak downtrend. The result of period analysis is that the annual runoff has no obvious period.The rainfall-runoff simulation is carried out by NAM model based on the observed data including rainfall, evaporation and temperature etc. Limited by the insufficient input data, the simulated runoff fails to satisfy with the observed hydrograph, with relative poor accurate simulated flood process. However the simulated result during dry period is better than that during flood period because of the relative regularity of runoff in Hotian Catchment during dry period.Based on observed flood data of 1981-1987, flood channel routing was carried out by MIKE11 HD model, and hydrodynamic model of channel in the catchment was established and verified by observed data from two gauging stations. The simulation result at Tonggu station is better than that at Xiaota station, which mainly because that the upstream area of Tonggu station is mainly in hilly regions while the upstream of Xiaota station mostly in desert, where lack of enough input data such as water diversion, evaporation, seepage and cross-section of channel etc. Therefore the simulated runoff at Xiaota station is relatively poor and the low sensitivity of roughness of channel to the result, which make it difficult to optimize parameters of the model.