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1、基于洪峰模数的山洪灾害雨量预警指标研究 李青 王雅莉 李海辰 张淼 李昌志 陈星 中国水利水电科学研究院 水利部防洪抗旱减灾工程技术研究中心 摘 要： 山洪灾害预警是防御山洪的重要非工程措施, 雨量预警指标是山洪灾害预警的关键。目前的雨量预警指标计算方法对水文气象资料条件以及模型建模率定都有很高的要求, 并不适用于基层防汛人员。因此, 本文基于全国山洪灾害调查评价成果数据, 提出了一种运用洪峰模数计算雨量预警指标的简便、易用的方法。该方法以小流域洪水计算推理公式为基础, 将公式中流量与流域面积的比值用洪峰模数表示, 得到基于洪峰模数的临界雨量估算公式, 并考虑流域土壤含水量等因素, 分析临界雨
2、量变化阈值, 最终得到雨量预警指标。本文以云南省绥江县双河小流域为例, 计算结果显示不同时段 (1 h、3 h、6 h) 净雨量和预警时段呈线性关系。降雨损失计算中洼地蓄水和植被截留在不同时段相同, 土壤下渗在不同的时段不相同。在此基础上, 计算不同土壤含水量条件下, 不同时段的雨量预警指标。最后, 对临界流量、降雨损失和预警指标进行了合理性分析, 结果显示预警指标和调查评价结果及实测降雨都比较接近, 计算的预警指标合理。本研究为基层山洪灾害预警提供了一种快速、便捷的预警指标计算方法, 为预警指标计算提供技术支持。关键词： 洪峰模数; 雨量预警指标; 山洪; 云南省; 双河小流域; 作者简介：
3、李青 (1982-) , 女, 山西静乐人, 硕士, 工程师, 主要从事山洪灾害预警技术方面研究。E-mail:收稿日期：2017-07-12基金：云南省山洪灾害防治预警指标和阈值分析方法研究 (JZ02032A032015) Rainfall Threshold for Flash Flood Early Warning Based on Flood Peak ModulusLI Qing WANG Yali LI Haichen ZHANG Miao LI Changzhi CHEN Xing Abstract： Flash flood early warning is an import
4、ant non-structural measure for flash flood prevention in China.Also, rainfall threshold is the key for flash flood early warning. At present, the method of calculating rainfall thresholds need a large amount of meteorological and hydrological data. Meanwhile, building the hydrological model and cali
5、brating parameters are difficult, which are not suitable for the flood control personnel. A simple and easy method, using flood peak modulus to calculate rainfall threshold, was proposed in this study based on national flash flood investigation and evaluation results. Rational equation is the basis
6、of the calculation method.The flood peak modulus in rational equation is expressed as a ratio of the flow to watershed area. Then, the critical rainfall formula is obtained. Using the Manning formula and national investigation and evaluation results, the flood peak modulus on the condition of critic
7、al flow is obtained, and the net rainfall is calculated.Based on the research results of the scholars, three aspects about the rainfall loss calculation are considered.They are depression storage, vegetation interception and soil infiltration. The sum of the net rainfall and the rainfall loss is the
8、 critical rainfall. Considering the factors such as soil water content of watershed, the rainfall threshold was finally obtained. In order to demonstrate this method, Shuanghe catchment in Suijiang County of Yunnan Province was chosen as the study area, of which the area is 89.12 km2. The calculated
9、 concentration time was 5.2 h. Thus, the duration was estimated to be 1 h, 3 h, and 6 h. The results indicated there was a linear correlation between the net rain amount and different rainfall durations. Depression storage and canopy interception was invariant during different rainfall durations, bu
10、t the infiltration was variable. For 1 h duration, initial infiltration was the main factor to consider; for 3 h, both initial infiltration and mid-term infiltration were considered; and for 6 h, steady infiltration also needed consideration besides the initial and medium-term infiltration. The calc
11、ulated critical rainfall for 1 h, 3 h, and 6 h were 38.6 mm, 64.8 mm, and 96.9 mm, respectively. Rainfall thresholds of different durations for flash flood early warning were estimated on basis of critical rainfall considering three different soil moisture conditions. Under dry soil moisture conditi
12、on, large rainfall loss leads to a large rainfall threshold; under wet soil moisture condition, contrary to the dry condition, small rainfall threshold is caused by small rainfall loss; and under medium soil moisture condition, the rainfall threshold was in medium. The rationality analysis on critic
13、al runoff, rainfall losses, and rainfall threshold was carried out in the end of this study. The results showed the calculated rainfall threshold by flood peak modulus method was approximated to the rainfall threshold obtained from national flash flood investigation and evaluation project. Also, the
14、y are in accord with the observed rainfall during flash flood events. Thus, the calculated results are reasonable in this study. This study provided a quick and convenient way of calculating rainfall threshold of flash flood warning for the grass root staffs and offered technical support for estimat
15、ing rainfall threshold correctly.Keyword： flood peak modulus; rainfall threshold; flash flood early warning; Yunnan province; the watershed of Shuanghe; Received： 2017-07-121 引言山洪是山丘区小流域由强降雨引起的突发性洪水1-2。近些年, 山洪灾害已经成为世界各类自然灾害中的一个主要灾种, 每年因山洪灾害所造成的人员伤亡和社会经济损失占各类自然灾害的比例持续上升, 引起各国政府和世界组织及山丘区居民的普遍关注, 部分国家已
16、将防御山洪上升为国家战略3。小流域山洪灾害预警是防御山洪的关键环节和技术难点, 而利用雨量预警指标进行山洪灾害预警是中国目前采用的主要方法4。当气象预报或实测降雨数据达到或超过雨量预警指标时, 通过发布预警信息, 安全转移危险区群众, 可以有效地减少人员伤亡和财产损失。国内外国学者开展了大量山洪灾害预警指标研究。在欧美国家和地区中, 美国的预警指标 Flash Flood Guidance (FFG) 最具代表性, 该方法基于临界流量, 同时考虑土层含水量变化, 利用分布式水文模型计算预警指标5-8。日本山洪灾害预警指标通过建立降雨强度与有效累积雨量之间的线性关系来确定9。中国早期采用的均为半经验方法10, 2013 年至今, 通过开展全国山洪灾害防治项目调查评价工作11, 极大程度上推进了中国山洪灾害预警指标的研究。但是上述方法对水文气象资料条件以及模型建模率定都有很高的要求, 适用于高层次专业人员及研究人员, 而对于县、乡、村一级的基层防汛人员并不适用。2010 年至今, 通过开展全国山洪
