Research On Drought Assessment And Forecast In Huangshui Basin Based On Mike She

Drought and water resources shortage has become one of the important factors ofrestricting China’s economic and social sustainable development. In recent years, almost allprovinces of China have happened drought and the loss increased, especially in the northwestarea. It is the urgent need to solve the problem of the current drought and to strengthendrought assessment prediction research.This paper simulated the process of precipitation and runoff in Huangshui Basin basedon the distributed watershed hydrological model MIKE SHE, and set up a drought assessmentand forecast model combining the simulated discharges with hydrologic drought index toresearch the drought in Huangshui Basin. Then the impact factors of drought are analyzedsuch as temperature, precipitation and potential transpiration. The essay mainly includes thefollowing six conclusions:(1) The distributed hydrological model in Huangshui Basin is successfully establishedbased on the fundamental data such as DEM, land use map, soil map, hydrogeological dataand the daily meteorological and hydrological data from1991to2006. These parameters arecalibrated such as manning numbers of overland flow, saturated moisture content andsaturated hydraulic conductivity of different soil type in the unsaturated flow, horizontalhydraulic conductivity, vertical hydraulic conductivity, specific yield, specific storage,drainage level, drainage time constant in the saturated zone and bed roughness.(2) The daily runoff process in Huangshui Basin is better simulated by the distributedhydrological model, and the annual runoff simulation result is better than the monthly runoff.Nash coefficient, water balance coefficient and correlation coefficient of the annual runoff atXining cross section during the calibration period is0.6846,0.9352and0.9252respectively;Nash coefficient, water balance coefficient and correlation coefficient of the annual runoff atXining cross section during the validation period is0.7695,0.9302and0.9229respectively.Nash coefficient, water balance coefficient and correlation coefficient of the monthly runoff atXining cross section during the calibration period is0.6478,0.7459and0.8960respectively;Nash coefficient, water balance coefficient and correlation coefficient of the monthly runoff atXining cross section during the validation period is0.6056,0.7139and0.8743respectively. (3) The following results are obtained based on anomaly percentage of runoff volume:drought of the main stream in Huangshui Basin in the year2001was the most serious,drought in the year2003and2004were a little serious, and there were no drought in the year2002and2005; drought of Beichuan River in the year2002and2006were the most serious,and there was no drought in the year2005; drought of the Xinachuan in the year2001and2006were the most serious, and there was no drought in the year2005. The following resultsare obtained based on runoff-denoted Z index: drought of the main stream in Huangshui Basinin the year2001was the most serious, and there were no drought in the year2005and2006;drought of Beichuan river in the year2001and2002were the most serious, and there was nodrought in the year2005; drought of the Xinachuan in the year2001,2002and2006were themost serious, and there was no drought in the year2005.(4) The following results are obtained based on drought disaster condition of QinghaiProvince: drought disaster in Qinghai Province in the year of2001,2002and2006wereserious, and the affected area and inundated area of crop was more larger, it is consistent withthe assessment result of hydrologic drought in this essay that drought in the year2001and2002were the most serious.(5) The runoff of the main stream and tributary in Huangshui Basin from2001to2006changes a little, and the runoff in the year2002is the least during the six years. Theconcentration of runoff among the main stream, Beichuan river and Xinachuan are the mosthighest in the year2001. The variation of precipation rate in the five region of HuangshuiBasin above Xining cross section from the year2001to2006is quite large, and the amount ofprecipitation in the year2002is the least during the six years. The variation of average airtemperature and potential evapotranspiration in the five region of Huangshui Basin aboveXining cross section during the six years is a little.(6) The amount of precipitation is the main important factor that affects the hydrologicaldrought in Huangshui Basin. The average air temperature and potential evapotranspirationaffect the hydrological drought a little in Huangshui Basin.