Study Of Runoff And Confluence Computation Methods In Ungauged Basins

In recent years, water problems such as floods, drought and water shortage, serious water pollution, have seriously hindered the development of social economy. At the same time, they have caused great damage to the safety of human life and property. Especially the flood disaster, which not only leads to death, deterioration of the environment, but also causes property losses, houses collapse, e.g. while reasonable flood forecast can effectively reduce flood damage, thus flood forecasting model is one of the focuses of hydrology research. Through the study of hydrology, flood forecast has been developed greatly. The accuracy of flood forecasting has been improved to some extent. But with the impact of human activities, regional flood where hydrology data is lacking brings a negative reaction to human activities. The flood forecast of ungauged regions has become the emphasis and key in the research. The research methods of flood runoff and confluence calcul ation differ between ungauged basins and rich data regions. So far, we are still lacking in the flood forecasting model with complete information system.Supported by the project of "Xinjiang Typical flood forecast model and data processing", this work has made an investigation into the computation mechanism of runoff and confluence for ungauged basins. On the basis of which, a flood forecast model is constructed. The model is applicable to ungauged basins in runoff data. By constructing the relation between the model parameters and the underlying surface characteristic values, we obtained the parameters for flood forecasting. The model is verified in Luhun reservoir and Nianyushan reservoir, based on which, appliing the model to ungauged basin(Kaidu River basin), and the forecasting results are analyzed and evaluated.(1) The computation mechanism of runoff and confluence for ungauged basin was studied. The runoff computation mode basing on runoff confficient “a” is constructed. Based on the database, the model analyzes the relationship between each flood rainfall runoff, calculates the runoff confficient “a”, and establishes the rainfall runoff correlated function. Surface confluence calculation adopted non-equidistant-isochrones unit line, where the unit line of each flood is calculated through linear reservoir storage routing and the underground runoff calculation uses the linear reservoir.(2) The flood forecasting model of ungauged basin was established. Based on the runoff and confluence calculation study of ungauged region, we construct an integrating mode for the flood forecast of no data area. And the parameters of the model is determined by analyzing the relationship between parameters of flood forecasting model and underlying surface characteristic values, so as to provide a solution to the existing problems of flood forecasting research in ungauged basin.(3) Analyzing the flood data of Luhun reservoir and Nianyushan reservoir, which are taken as typical basins to verify the mode. On the basis of the validation, the model is applied to the ungauged region(Kaidu River basin), and the simulation results are analyzed and evaluated, where the causes of error were analyzed.