【作者】 李洁；

【导师】 莫淑红；

【作者基本信息】 西安理工大学 ， 水文学及水资源， 2017， 硕士

【摘要】 人类活动导致流域下垫面条件发生变化,改变了流域洪水径流特性。近年来,大理河流域年最大洪峰值有显著减小的趋势,洪水发生次数及量级均有减少,且同一降雨量级下产流量不断减小。种种迹象表明,由于人类活动的影响,大理河洪水规律已经发生了很大改变,威胁到区域水资源安全。本文以大理河流域为研究区域,选择大理河流域内青阳岔、岔巴沟、小理河流域为研究对象,分析了各研究流域的暴雨洪水特征的变化趋势,并基于多水源时变增益模型对研究流域进行次洪模拟,分析模型在大理河流域的适用性,通过下垫面变化前后不同的产汇流参数对不同量级的次洪进行模拟分析,估算下垫面变化对洪水规律的影响程度。主要研究内容如下:(1)根据大理河流域Landsat MSS/TM遥感资料分析青阳岔、岔巴沟、小理河流域70年代到80年代植被覆盖变化。结果表明,各流域植被覆盖度从1970s到1980s均呈增加的趋势,整体有由低覆盖度及中覆盖度转向中高覆盖度的趋势。调查收集了大理河流域水土保持治理规模,调查结果表明大理河流域在1970s修建了大量的工程措施。(2)采用线性趋势回归分析法和Mann-Kendall非参数秩次相关检验法分析各流域年最大洪峰及其对应的次洪量、次暴雨量和洪峰滞时等参数的时间序列的趋势,采用双累积曲线法、有序聚类法、滑动F检验法和滑动T检验法分析参数的变异,确定了参数可能变异点。(3)选择各研究流域暴雨洪水特征发生变异前后的不同量级的相似降雨产生的洪水,分析比较其洪水差异,初步结果表明,下垫面变化导致流域洪水洪峰和次洪量减小。(4)采用多水源TVGM模型对次洪进行模拟,选择多场暴雨洪水对模型进行参数率定和验证,模拟洪水过程与实测洪水过程拟合较好,洪峰及洪量误差整体在20%以内,Nash效率系数在0.7以上。结果表明,MTVGM模型在大理河流适用性较好,可以用来分析流域下垫面变化对洪水规律的影响。选择各研究流域大、中、小型洪水,分别在下垫面变化前后两组不同的产汇流参数下进行次洪模拟。结果表明,流域下垫面变化使得洪水洪峰及次洪量发生衰减,衰减率随洪水量级的减小而增大,且洪峰流量比次洪量衰减率大;对洪水产生了明显的削峰以及坦化效果,其中对大中水主要为削峰作用,对偏小型洪水主要为坦化作用。更多还原

【Abstract】 Change of underlying surface condition caused by human activities, changes characteristics of flood runoff in river basin. In recent years, in Dali River basin, annual maximum peak has a significantly decreasing trend; the number and magnitude of floods are reduced; the runoff at the same rainfall level is decreased. There are indications that, due to the impact of human activities,regulation of runoff yield and concentration has changed greatly. This change threatens regional water security. This paper taking Dali River basin as the study area, and choses Qingyangcha basin,Chabagou basin and Xiaoli River basin as research objects. In this paper, we analyzed the trends of rainstorm flood features in each research basin. Conducting flood simulation and analyzing the applicability of the model in Dali River basin based on multi-source Time Variant Gain Model(MTVGM). By the different parameters of runoff yield and flow concentration before and after the change of underlying surface condition, we conduct each magnitude of flood simulation, and estimate the influence degree of the change of underlying surface condition on the regulation of runoff yield and concentration. The main research contents are as follows:(1) According to the remote sensing data of Landsat MSS / TM in Dali River Basin, the vegetation cover changes in the 1970s and 1980s were analyzed. The result shows that the vegetation coverage of each basin increased from 1970s to 1980s. It has an overall trend from low coverage and moderate coverage to high coverage. At the same time, we collect the soil and water conservation measures and size in Dali River basin.(2) Using linear trend regression and Mann-Kendall trend test analyze the trend of the time series of annual maximum peak, flood volume, storm volume and flood peak delay time hydrologic parameters. Use double mass curve method, sequence cluster analysis, smoothing F test and smoothing T test analyze the variation of hydrologic parameters, and determine the aberrance point of parameters.(3) Selecting floods under similar rainfall before and after the variation of rainstorm flood features in each research basin, and comparing the characteristic changes of each flood. The preliminary results show that, the change of underlying surface condition leads to the decrease of flood peak and flood volume.(4) Using MTVGM model to simulate flood, calibrating and verifying the model parameters,the results show that the shapes of simulated flood hydrograph and measured flood hydrograph were fitting good. The error of most flood peak and flood volume is less than 20%, and the value of Nash-Sutcliffe efficiency coefficient is more than 0.7. Therefore, we consider that the model is well suited for the Dali River basin, and the model can be used to analyze underlying surface impact degree on the regulation of runoff yield and concentration. Selecting inundation, medium flood, miniature flood in each research basin to be simulated by different model parameters before and after the change of underlying surface condition. The results show that the change of underlying surface condition leads to the decrease of flood peak and flood volume, and the decay rate increases with the decrease of the flood magnitude, and the decay rate of flood peak rather than the decay rate of flood volume. At the same time, it also leads to flood peak clipping and attenuation actions. Among them, for inundation and medium flood the main role is peak clipping;for miniature flood the main role is attenuation actions.更多还原