三角形综合单位线法洪峰预报研究

为了减轻洪灾给广东省中小流域桥梁带来的危害,基于广东省综合单位线法和影响线理论,提出了三角形综合单位线洪峰实时预报法,结合现行三角形单位线模型特点和广东省综合单位线三角形简化结果,建立了三角形综合单位线模型;确定涨水历时计算依据,选取合适的涨、退水历时比值,利用流域历史洪水资料标定峰值;将实时雨量当作移动荷载组在已标定模型上加载,计算实时流量过程线,确定洪峰流量、洪峰水位、峰现时间等参数,对既有桥梁进行水害实时预报工作。研究结果表明,三角形综合单位线法洪峰实时预报需要的参数少,计算过程简单,预报结果可靠,可以用来预估洪水灾变的可能性及其危险程度。

Research on Peak Stage Forecast Based on Triangle Synthetic Unit Hydrograph Method

In order to reduce the bridge flood disaster in small and medium watersheds in Guangdong, a peak stage forecast method based on triangle synthetic unit hydrograph is put forward through Guangdong synthetic unit hydrograph method and influence line theo-ry. Firstly, combined with characteristics of the present triangular unit hydrograph models and simplified analysis results of Guangdong synthetic unit hydrograph, the triangular synthetic unit hydrograph model is set up. Secondly, rising duration calculation formula is es-tablished, the suitable ratio of rising duration to falling duration is chosen, and the peak value of the model is calibrated by data of his-torical flood. Finally, the real-time discharge hydrograph is calculated by loading real-time rainfall series as a set of moving loads on the calibrated model, so the real-time data of flood characteristic, such as peak discharge, flood-peak stage, flood-peak time, etc, can be got, and real-time flood forecast of bridges can be done. The results show that real-time peak stage forecast based on triangle syn-thetic unit hydrograph method requires less parameter, and is convenient in practical application and reliable in forecast accuracy. So the possibility and the magnitude of flood disaster could be forecast ahead of time.