Research On Flood Control Forecast Operation In Later Flood Season Ⅱ In Huanren Reservoir

Misdistribution of space and time in precipitation determine the water resources. Precipitation concentrated in flood season in northern China and rainfall rare after the flood season lead to imbalance between supply and demand of water resources in northern China. In current reservoir real-time flood dispatching, using design of conventional scheduling and its rules in bondage to the design of the limited water level and on the basis to a real-time flow and water level would result in overmuch abandoned water in many northern reservoir during flood season. There is no enough water filling up the reservoir after flood season. It is great pity that water resources are wasted. Later flood season is a transition from flood season to non-flood season. Flood control way during this period is not only related to the flood control and its efficiency in this period, but also related to the normal operation of the reservoir after the flood season. Study of reservoir operation for forecasted flood in this period is to the benefit of improving the flood resources utilization and giving play to comprehensive benefits. At present, precision of flood forecast information and short-term rainfall forecast information reach the level of guiding the real-time operation in the reservoir. Based on the theory of flood forecasting and reservoir scheduling method and flood characteristic by stages in northern China, this paper study the reservoir operation for forecasted flood in later flood season II in Huanren reservoir by considered flood forecast information and24h rainfall forecast information hoping to improve the reservoir generation benefit and no risks added. Taking Huanren reservoir as the research background, the specific work and innovation are as follows:(1)In this paper, runoff producing forecasting model use rainfall-runoff correlation curve and concentration forecasting model use unit line method, analyzing20floods in later flood season II in Huanren reservoir and forecast error distribution. Using coefficient of DC and RE(relative error) of flood forecast results is evaluated.In order to evaluating flood forecast standard, flood Information Prediction Standard (GB/T22482-2008) is needed. Analysis results show that, Flood forecast accuracy is class A and flood forecast error will not bring about aerial drainage bypass grade in the reservoir. Result of precision analysis and error analysis provide the premise condition for study scheduling discipline of reservoir operation for forecasted flood by flood forecast information.(2)Taking Huanren reservoir above drainage basin as the study area, on the basis of rainfall level classification standards from meteorological department and forecast accuracy analysis method,24h rainfall forecast information and frequency distribution of the measured daily precipitation in later flood season II from1999to2010are analyzed. Analysis results show that, the period of24h precipitation forecast future information is high precision, which provides the premise condition for study scheduling discipline of reservoir operation for forecasted flood by24h rainfall forecast information.(3)On the basis of analysis of the availability of flood forecast information and24h rainfall forecast information, flood control and water storage risk of the reservoir when error appears in forecast information are analyzed. Based on the theory of flood forecasting and reservoir scheduling method and flood characteristic by stages in northern China, this paper study the reservoir operation for forecasted flood in later flood season II in Huanren reservoir by considered flood forecast information and24h rainfall forecast information. In addition, the reservoir operation for forecasted flood in later flood season II is tested by design flood and the actual flood. The results show that, new dispatching rule can increase the hydropower generation benefits without bringing any more flood risk.Finally, the achievements and defects of paper are summarized; the future research direction is prospected.