基于HBV模型的淮河流域洪水致灾临界雨量研究

根据流域暴雨洪水致灾机制,文章提出了考虑前期基础水位的动态致灾临界雨量指标,并以淮河上游地区为例,基于HBV水文模型建立了降水-流量-水位关系,并根据这种关系确立了临界雨量确定的方法流程.首先基于历史水文数据率定和验证模型,得到适用于研究区的最优化模型参数,然后构建洪水上涨期水位流量关系,最后以是否达到致灾水位为标准,通过模型试算并结合水位流量关系曲线反推出致灾临界雨量值.在淮河上游地区的研究中,利用2002-2009年逐日气象水文数据对HBV模型进行了参数率定和检验,并针对洪水过程进行了参数优化,经过率定后HBV模型对王家坝以上流域具备较好的适用性,对典型洪水过程模拟的确定性系数和NASH效率系数均在0.8以上;根据王家坝站实测流量水位数据,构建了概化的单一关系曲线;结合HBV模型和水位流量关系得到了王家坝以上流域的动态致灾临界雨量指标,临界雨量值随前期基础水位升高而减小,并且随着前期水位的变化,临界雨量值呈现了明显的非线性响应特征.

Mechanism Oriented Approach for Estimating Critical Rainfall of Flood Disaster: A Case Study Based on HBV Model

According to the mechanism of rainstorm flood, we propose a dynamic critical rainfall index associated with the former water levels. The method for calculating critical rainfall of flood hazard is established by using HBV model in the upper Huaihe River Basin. First of all, the optimized model parameters is determined through the model calibration and validation. The stage discharge relationship is then established for the rising levels of flood. Finally, the critical rainfall is determined according to the hazard water level by repeated model simulation. The case study in the upper Huaihe River Basin indicated that HBV model can well simulate the process of flood response to rainfall after model calibration by using daily meteorological and hydrological data for the period of 2002-2009. The model combined with the stage discharge relationship is then used to calculate the dynamic critical rainfall over the Wangjiaba sub region. The critical rainfall decreases with the increase in former water level. The variation of critical rainfall with different former water level shows significantly nonlinear response characteristics.