基于临界雨量的陕南地区山洪灾害预警指标研究与应用

发布时间：2018-07-31 09:24

【摘要】：山洪灾害是由降雨引起的一种自然灾害,主要受流域的降雨特性和下垫面条件等因素影响。陕西省山洪灾害频发,每年均会造成严重的人员伤亡和财产损失。小流域山洪灾害预警预报研究可为山洪灾害的预防和治理提供理论基础和技术依据。本文分析了陕西省陕南地区山洪灾害成因、特点及发展趋势,并结合山洪灾害防治工作的开展情况,对防治工作的效益进行分析。针对无资料和资料不足或缺乏的山区小流域,分别采用水位流量反推法和TOPMODEL流域水文模型法进行预警指标的确定。采用经验公式法、推理公式法和瞬时单位线法推求冷水河流域设计洪水,通过分析比较计算结果并确定各方法适用性。得到如下结论:(1)陕南地区山洪灾害主要由突发的强降雨形成。由于大气环流条件和地形因素短期内不会有较大的改变,因此陕南地区山洪灾害防治现状短时期内不会有较大的改观。通过分析近年山洪灾害造成的生命财产损失,可知由于山洪灾害防治项目的开展,灾害损失有所减少,工作成效较明显。(2)针对无资料小流域采用经验公式法、推理公式法和瞬时单位线法计算设计洪峰流量,均有一定可行性,三种方法计算结果存在差异。经分析可知,经验公式法因考虑影响因素过少,在运用时仅能作为参考结果。瞬时单位线法计算所得设计洪峰流量偏大,适用于流域面积较大的区域。推理公式法计算过程比较简洁,能较好地反映流域实际情况,针对无资料且流域面积较小的流域,推理公式法有较好的适用性。(3)采用水位反推法计算山区小流域山洪雨量预警指标,假定不同的前期土壤含水量,计算相应的临界雨量值,即为立即转移预警雨量值,可实现较简单的动态雨量预警预报。采用水位流量反推法计算临界雨量时,在相同土壤含水量情况下,临界雨量值随着时段的增大而增大,变化速率随着时段的增大而减小,土壤含水量对临界雨量的影响随着时段的增长而减小;相同时段的临界雨量随着土壤含水量的增大而减小,且变化速率随着土壤含水量的增大而减小,即土壤含水量对临界雨量的影响随着其增大而减小。(4)采用TOPMODEL水文模型法确定雨量预警指标。提取流域DEM数据并进行处理得到流域地形指数分布曲线,通过人工试错法率定模型参数。由模拟结果知TOPMODEL模型可应用于陕南湿润地区,能较好地模拟径流过程。通过试算法反算不同土壤湿润程度下的临界雨量值。(5)对比分析水位流量反推法和TOPMODEL流域水文模型法确定临界雨量值,可知水位流量反推法确定的预警指标值较小,TOPMODEL模型法确定的预警指标值较大。与历史洪水资料相比较,知两种方法均可进行预警指标的计算,可应用于山洪预警预报工作中。
[Abstract]:Mountain flood disaster is a natural disaster caused by rainfall, which is mainly influenced by the rainfall characteristics of the basin and the conditions of the underlying surface. The flood disasters in Shaanxi province are frequent and cause serious casualties and property losses every year. The study of mountain flood disaster early warning and prediction in small watershed can provide theoretical basis and technology for the prevention and control of mountain torrents. This paper analyzes the causes, characteristics and development trend of mountain torrents in southern Shaanxi Province, and analyzes the benefit of the prevention and control work in the light of the prevention and control work of mountain torrents. In view of the small and lack of data and data, the water flow backstepping method and the TOPMODEL watershed hydrologic model method are adopted respectively. The empirical formula method, the inference formula method and the instantaneous unit line method are used to calculate the design flood in the cold water river basin. The results are analyzed and compared and the applicability of each method is determined. The following conclusions are obtained: (1) the mountain flood disaster in southern Shaanxi is mainly caused by the sudden heavy rainfall. There will be no big changes in the period, so there will not be a great change in the current situation of flood disaster prevention and control in southern Shaanxi. By analyzing the loss of life and property caused by mountain flood disasters in recent years, it is known that the loss of disaster loss has been reduced and the work efficiency is obvious because of the project of flood disaster prevention and control. (2) the use of the small watershed for no data is adopted. The experimental formula method, the inference formula method and the instantaneous unit line method are feasible to calculate the flood peak flow. The calculation results of the three methods are different. The analysis shows that the empirical formula method can only be used as a reference result when the influence factors are too few and can be used as the reference result. The calculation process of the inference formula method is relatively simple and can better reflect the actual situation of the basin. The reasoning formula method has good applicability for the basin with no data and the basin area is small. (3) the early warning index of mountain flood rainfall is calculated by the water level backstepping method, and the different early soil water content is assumed and the calculation phase is assumed. The critical rainfall value, that is, to transfer early warning rainfall value immediately, can realize a relatively simple dynamic rainfall forecast. When the critical rainfall is calculated by the reverse method of water level and flow, the critical rainfall value increases with the increase of the period of time, the rate of change decreases with the increase of the time period, and the soil water content is critical. The effect of rainfall decreases with the increase of the period of time; the critical rainfall in the same period decreases with the increase of soil water content, and the change rate decreases with the increase of soil water content, that is, the influence of soil water content on the critical rainfall decreases with the increase of soil water content. (4) the rainfall early warning index is determined by the TOPMODEL hydrological model method. The watershed DEM data are processed to get the distribution curve of the basin topographic index, and the model parameters are determined by the artificial test and error rate. The simulation results know that the TOPMODEL model can be applied to the humid region of Southern Shannan, and the runoff process can be simulated well. The critical rainfall value under different soil wetting degree is calculated by the test algorithm. (5) the contrast analysis of the water level and flow rate is made. The method of pushing and the hydrological model of the TOPMODEL basin determines the critical rainfall value. It is known that the early warning index value determined by the backstepping method of the water level and flow is smaller, and the early warning index value determined by the TOPMODEL model method is larger. Compared with the historical flood data, two methods can be used to calculate the early warning index, which can be applied to the early warning and prediction work of the mountain torrents.
【学位授予单位】：西北农林科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV87;X43

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