南宁市江南区农村基层预报预警系统预警指数研究

Study of warning indexes for rural basic-level flood prevention forecast and warning system of Jiangnan District in Nanning City

介绍了农村基层防汛预报预警体系建设中,山洪灾害影响村落和低洼易涝村落雨量预警指标计算的方法。对典型山洪灾害影响村庄,在实测断面测量资料的基础上,根据已分析出的设计洪水和水面线成果,计算其成灾水位对应的临界流量,通过假设汇流时间下的雨量数据,按对应雨型经点面转换后的时程分配得到暴雨过程,并以暴雨过程数据作为模型输入,根据模型参数进行反复试算,计算出其成灾水位对应的临界流量,并在洪水达到临界流量时对其形成的成灾水位进行测算,此时假定的时段雨量即为该级别所对应的临界雨量。对于低洼易涝村落,根据易涝区水位容积曲线,查取成灾水位对应容积,与流域汇水面积相除得到流域径流深,通过径流系数反算面雨量。

An introduction was made on the method of calculating the rainfall warning indexes for the mountain flood affected villages and low lying and easily waterlogged villages which was conducted during the construction of rural basic-level flood prevention forecast and warning system.For the typical mountain flood affected villages,based on the measured sectional data,according to the analysis results of design flood and water surface profile,the critical flow corresponding to the disaster water level was calculated by use of the rainfall data within the assumed confluence period,obtaining the rainstorm process according to the time-course distribution of the corresponding rain pattern after point surface conversion,the rainstorm process data being used as model input,and repeated trial calculations being performed according to the model parameters.The disaster water level when the flood flow reaches the critical flow and the rainfall within assumed period is the corresponding critical rainfall was also calculated.For the low lying and easily waterlogged villages,the volume corresponding to the disaster water level was found according to the level-volume relationship curve of easily waterlogged area;the runoff depth was calculated with the volume divided by watershed catchment area;and the area rainfall was calculated inversely by runoff coefficient.