Study On Flood Forecasting Scheme Of Menlou Reservoir

The flood disaster is one of the top ten natural disasters that threaten human survival. It threatens people’s lives and property, while people suffer enormous losses of agriculture and industry. Nowadays, as one of important non-structural measures for flood control, flood forecasting can help human beings not only defense flood and reduce flood losses, but also control and make use of water resources. After people built a lot of small reservoirs on upstream, this area’s runoff and concentration had been changed, so the existing flood forecasting scheme in Menlou watershed is low-precision. Using relative data such as basin’s separated floods, antecedent soil moisture content, the relationship between storage capacity and area of small reservoir, a method is given to make flood forecast considering these small reservoirs’closure quantitatively. The forecasts’accuracy is improved greatly comparing with neglecting small reservoirs’influence. This method’s rationality is analyzed in this paper.The main contents and conclusions are as follows:Analyzing the status and hydrological characteristics of Menlou basin, some improvements are made to the existing flood forecasting scheme. Both the DHF flood forecasting model and the experience unit hydrograph model are introduced. On the basis of the watershed evapotranspiration and soil storage capacity parameters of DHF model, this paper simplifies these parameters further. And a mothed is introduced to improve particle swarm optimization to optimize model parameters.This paper analyzes the impact of small reservoir on the runoff and concentration. Using relative data such as basin’s separated floods, antecedent soil moisture content, the relationship between storage capacity and area of small reservoir, a method is given to make flood forecast considering these small reservoirs’closure quantitatively. The forecasts’ accuracy is improved greatly comparing with neglecting small reservoirs’influence. This method’s rationality and potential limitations are analyzed from typical flood and parameters.Reasons, which influence forecasts’accuracy, are analyzed in this paper. The rainfall center of river flood is divided into three types:upstream、downstream and all basin. And using different parameters to simulate the three types of floods, the forecasts’accuracy is enhanced further. Defects are discussed from relative information、impact of small reservoirs and flood routing, respectively.