【作者】 张宇；

【导师】 武鹏林； 邢肖鹏；

【作者基本信息】 太原理工大学 ， 水利工程（专业学位）， 2020， 硕士

【摘要】 山西省位于半干旱半湿润地区,地形以山地为主,山区小流域星罗棋布。其汛期洪水形式多为“陡涨陡落”,具有很强的突发性与危害性,而且此类地区往往缺乏水文观测资料,洪水预报较为困难。因此对半干旱半湿润无资料山区小流域进行水文预报研究具有重要的科学意义和实用价值。双超产流计算模型在半干旱半湿润地区的良好适用性已由前人研究验证。地貌瞬时单位线(GIUH)是一种适用于无资料地区的汇流计算方法,以往其研究应用集中于南方湿润地区,且多数研究只针对整个流域构建地貌单位线,难以反映流域内地貌特征的空间差异,此法在北方半干旱半湿润地区的应用尚少。利用上述方法分单元进行产汇流计算,结合河道汇流构建双超-地貌瞬时单位线耦合模型(以下简称“耦合模型”),通过将耦合模型应用于水文资料充足的流域,对模型的适用性进行验证,对参数的敏感性进行探究,以便将其进一步推广至半干旱半湿润地区的无资料流域。本文以山西省忻州市王家会水文站流域为研究对象,主要研究内容及结论如下:(1)基于数字高程模型(DEM)的子流域划分与地貌参数提取。对研究区DEM资料进行水文分析,利用河网密度法确定出流域集水面积阈值为3 km~2;在此基础上提取流域河网水系,然后根据水系分布划分出7个子流域;利用泰森多边形法获取各子流域的雨量站权重;利用Strahler法对河网进行分级,并获取各子流域的地貌参数。(2)地貌单位线的计算与分析。根据R-V GIUH理论对子流域降雨质点的汇流路径进行划分,根据地貌参数计算路径概率与状态持留时间概率密度函数,进而求得GIUH公式;通过S曲线法将瞬时单位线转换为时段单位线。将双超产流、地貌单位线汇流及河道汇流进行耦合。结合流域地理特性对比分析各子流域单位线的差异,将影响单位线形状的地貌因素归纳为流域面积、水系形状、异级河段长度(或异级汇水面积)以及坡度四项,且在不同的流域中起主导作用的因素也不同。(3)洪水预报研究与分析。利用耦合模型对王家会水文站流域25场历史洪水进行模拟研究。结果显示,洪峰流量合格率为92.0%,径流深合格率为64.0%,峰现时间合格率为96.0%,三个预报项目的平均合格率为84.0%,达到了乙级精度。且确定性系数大于0.70的场次占总场次的72.0%。说明耦合模型在王家会流域模拟结果较为理想,具有良好的适用性。耦合模型对大中型洪水模拟效果优于小型洪水;单峰陡涨陡落型洪水模拟效果优于涨落平缓的洪水;多峰且洪峰不叠加的洪水模拟效果优于多峰且峰间重叠的洪水。耦合模型中主要的产流参数有Sr、b、Ks、、δ,其中Sr、Ks、与洪峰和径流深呈负相关变化,b、δ与洪峰和径流深呈正相关变化,各参数因其物理意义及作用时期的差异而对洪峰流量和径流深表现出不同的敏感性,从洪峰流量角度分析参数敏感性排序为Sr>b>Ks>>δ,其中Sr为敏感参数,b、Ks、均为较敏感参数,δ敏感性较低;从径流深角度分析参数敏感性排序为Sr>δ>>Ks>b,其中Sr为敏感参数,δ、均为较敏感参数,b、Ks敏感性较低。汇流参数a与洪峰流量呈正相关关系,对径流深没有影响,参数a的增大会导致峰现时间的提前。更多还原

【Abstract】 Shanxi Province is located in the semi-arid and semi-humid region with mountainous terrain.The small watersheds are scattered all over the place.During the flood season,the rising and falling sections of the flash floods are quite steep,causing them to be sudden and harmful.In addition,there is often a lack of hydrological observation data in such areas,so the flood prediction is difficult.Therefore,it is of great scientific and practical value to analyze flash flood forecasting for ungauged basins in semi-dry and semi-humid region.It has been verified by previous studies that the Double-excess runoff generation model has good applicability in semi-dry and semi-humid areas.The geomorphologic instantaneous unit hydrograph（GIUH）is a method for calculating runoff concentration,which is applicable to ungauged basins.At present,the domestic research and applications of this method focus on the humid areas in south China,and most studies build GIUH based on the entire watershed,which was difficult to reflect the spatial differences of geomorphic characteristics in the watershed.The applications of this method in semi-dry and semi-humid region is still rare.By applying the coupling model to the basin with sufficient hydrological data,the applicability of the model is verified,and the sensitivity of parameters is explored,so as to further extend it to the similar areas.This paper takes Wangjiahui watershed in Xinzhou city,Shanxi Province as the research object.The main research contents and conclusions are as follows:（1）Sub-basins division and geomorphic parameters extraction based on DEM.Hydrologic analysis is carried out on DEM,and the critical contributing area is determined to be 3 km²by river network density method.Then,7 sub-basins are divided by the distribution of the river network,and the weight of each rainfall station was obtained through the Thiessen polygon method.Finally,the Strahler method was used to classify the river network and obtain the geomorphologic parameters of each sub-basin.（2）Calculation and analysis of geomorphic unit hydrograph.According to the R-V GIUH theory,the runoff paths of the precipitation particles are determined.The path probabilities and retention time probability density functions are calculated by the geomorphic parameters,and then the GIUH formulas are derived.The instantaneous unit hydrographs are converted into time unit hydrographs by S curves.Based on the comparison and analysis of unit hydrographs by geographical characteristics,the geomorphologic factors affecting the shape of unit hydrographs are summarized into four items:basin area,river network distribution,length of different grade river reach（or area of different grade catchment）and slope.Besides,the dominant factors are different in different basins.（3）Research and analysis of flood forecasting.The coupling model is used to simulate 25 historical representative rainfall events in the Wangjiahui watershed.The results show that the qualified rate of peak flow is 92.0%,the qualified rate of runoff depth is 64.0%,the qualified rate of peak time is 96.0%,and the average qualified rate of the three forecast items is 84.0%,the simulation accuracy of this model is up to grade B.Moreover,the deterministic coefficient greater than0.70 accounted for 72.0%.The results show that the coupling model has good applicability in Wangjihui watershed.In terms of simulation effect,the big floods are better than small floods.The steep floods with single peak is better than the gentle floods.The floods with multiple peaks and no superposition between peaks is better than floods with overlapping peaks.The Sr,b,Ks,₀ andδare the main runoff generation parameters in this model.The Sr,Ks and ₀ are negatively correlated with peak flow and runoff depth.The b andδare positively correlated with peak flow and runoff depth.Due to the difference of physical meaning and action period,each parameter shows different sensitivity to flood peak flow and runoff.From the perspective of peak flow,the parameter sensitivity order is Sr>b>Ks>>δ.For peak flow,the Sr is the most sensitive parameter;the b,Ks and ₀ are sensitive parameters;theδis insensitive parameter.From the perspectives of runoff depth,the parameter sensitivity order is Sr>δ>>Ks>b.For runoff depth,the Sr is the most sensitive parameter;the ₀ andδare sensitive parameters;the b and Ks are insensitive parameter.The runoff concentration parameter a is positively correlated with the peak flow,but has no effect on the runoff depth.The peak time is advanced with the increase of a.更多还原