【作者】 高敏；

【导师】 孔凡哲；

【作者基本信息】 中国矿业大学 ， 水利工程（专业学位）， 2022， 硕士

【摘要】 我国洪涝灾害频发,流域水文模型已经成为洪水预报的主要工具。计算单元是流域水文模型构建的基础,计算单元的划分对流域水文模型影响的研究非常重要,关系到流域水文模拟和预报精度的好坏。本论文基于流域水文模型,结合谭家河流域的DEM以及洪水资料,主要围绕计算单元划分对流域水文模型的模拟结果及模型参数的影响开展研究。探究了计算单元划分与流域形状系数的关系,为机理分析提供依据,并以河网汇流和河道演算理论为基础,从机理上分析了计算单元划分对汇流计算方法及对河网汇流曲线的影响机理,研究内容及结果如下:(1)流域水文模型的构建。采用自然流域作为模型计算单元,划分了6组不同的计算单元划分方案,分别是:基础方案方案1(7个计算单元),方案2和方案3在方案1的基础上进行横向计算单元合并,方案4、方案5和方案6进行了纵向计算单元合并。根据划分的6组计算单元方案,构建了6个水文模型。产流计算采用三水源新安江模型,河网汇流采用分布式单位线,河道演算采用马斯京根模型。(2)计算单元划分对模型模拟结果的影响。基于构建好的模型和8场洪水资料对基础方案1进行模拟率定,选择模拟效果最优的汇流时间系数及其他参数,将这组参数应用到其他方案上,统计分析这些方案的模拟结果。统计结果为:方案2及方案3的合格率为100%;方案4合格率为50%,洪峰流量变化较大;方案5及方案6合格率为37.5%,洪峰流量变化较大,部分洪水峰现时间提前。(3)计算单元划分对模型参数的影响。基于默认参数下,不同划分方案模拟结果不理想,要得到相同或相近的模拟结果,需要调整各方案模型中汇流时间系数以改变河网汇流单位线。经过重新率定,各方案下的汇流时间系数不同,随着计算单元个数的减少,呈变大趋势,模拟精度提高。(4)计算单元划分与形状系数之间的关系。基于白土岗流域、伊河流域以及汉江流域的三个支流,通过给定不同的集水面积阈值划分流域的计算单元,将不同集水面积阈值下的流域形状系数均值以箱型图为工具统计出来。结果表明,形状系数随着计算单元个数的减少而变小,流域形状逐渐趋于狭长。(5)计算单元划分对模型的影响机理。1)对比分析了不同计算单元划分方案中的汇流计算方法。结果表明:不同单元划分方案,模型采用的汇流计算方法组合不同。2)分析了计算单元划分对单位线计算结果的影响。结果表明:在参数相同的情况下,计算出不同形状单元的单位线与实际汇流特征的吻合程度不同。得出的结论为:不同的单元划分方案,对应不同的汇流计算方法组合及不同的计算单元形状,导致在参数相同的情况下,具有不同的模拟结果,要得到同样的模拟结果,需要采用不同的汇流参数。提出了计算单元合理划分应遵循的原则:横向宜合并,纵向宜拆分。本文研究成果对采用水库调蓄的汇流曲线计算方法的流域水文模型的应用,具有积极意义。本论文有图50幅,表16张,参考文献84篇。更多还原

【Abstract】 Flood disasters occur frequently in China,and the watershed hydrologic model has become the main tool for flood prediction.The calculation unit is the basis of the construction of the watershed hydrological model,and the study of the division of the calculation unit on the watershed hydrological model is very important,which is related to the accuracy of the watershed hydrological simulation and forecast.Based on the watershed hydrological model,combined with the DEM and flood data of the Tanjiahe watershed,this thesis mainly focuses on the simulation results of the calculation unit division on the watershed hydrological model and the influence of the model parameters.The relationship between the calculation unit division and the watershed shape coefficient is explored.rovides the basis for the mechanism analysis.Based on the theory of river network confluence and river calculus,the mechanism of the calculation unit division on confluence calculation method and confluence curve of hydrographic net is analyzed.The research content and results are as follows:(1)Construction of the Watershed Hydrological Model.The natural basin is used as the model calculation unit,and 6 different calculation unit division schemes are divided,respectively are: scheme 1 as the basic scheme(seven calculation units),scheme 2 and scheme 3 were combined with horizontal calculation units on the basis of scheme 1,and scheme 4,scheme 5 and scheme 6 were combined with vertical calculation units.According to the six groups of calculation unit scheme,six hydrological models are constructed.Flow production calculation was used Xin’anjiang hydrological model with three water sources,distributed unit line is used for river network confluence,and Masjingen model is used for river calculation.(2)Influence of calculation unit division on simulation results.Based on the established model and eight floods data,the basic scheme 1 was calibrated,and the confluence time coefficient and other parameters with the best simulation effect were selected.The parameters were applied to other schemes,and the simulation results of these schemes were statistically analyzed.Statistical simulation : the qualified rate of Scheme 2 and 3 is 100%;the qualified rate of Scheme 4 is 50%,the flood peak dischanges varies greatly;the qualified rate of Scheme 5 and 6 is 37.5%,the flood peak dischanges varies greatly and the some flood peaks are ahead of schedule.(3)The influence of unit division on model parameters.Based on the default parameters,the simulation results of different division schemes are not ideal.To obtain the same or similar simulation results,the confluence time coefficient in each scheme model is adjusted to change the confluence unit line of the river network.After the redetermination,the confluence time coefficient under each scheme is different,with the decrease of the number of calculation units,and the simulation accuracy improves.(4)The Relationship Between the Calculation Unit Division and the Shape Coefficient.Based on the Baitugang watershed,Yihe watershed and the tributaries of Hanjiang watershed,The calculation units of watershed were divided by given different catchment area thresholds,and the mean of watershed shape coefficients under different catchment area thresholds was calculated by box plot tool.The results show that the shape coefficient decreases with the number of computed units reduce,and the basin shape tends to be narrow.(5)The influence mechanism of computational unit division on the model.1)The confluence calculation method in different computing unit division schemes is compared and analyzed.The results show that the combination of convergence calculation methods is different for different unit calculation.2)The influence of unit division on the calculation result of unit line is analyzed,The results show that under the condition of the same parameters,the agreement between the calculated unit lines and the actual confluence characteristics is different.The conclusion is as follows:different unit division schemes correspond to different confluence calculation method combinations and different calculation unit shapes,resulting in different simulation results with the same parameters,and to get the same simulation results,different confluence parameters need to be adopted.Put forward the principle of reasonable division of calculation units should be followed: horizontal should merge,vertical appropriate split.The research results of positive significance to the watershed hydrological model based on reservoir regulation and storage.There are 50 figures,16 tables and 84 references in this thesis.更多还原