【作者】 林韵；

【导师】 潘文斌；

【作者基本信息】 福州大学 ， 环境科学， 2010， 硕士

【摘要】 洪水是自然灾害中最为严重的一种，有着频率高，范围大，速度快的特点。福州地处我国东南沿海，汛期暴雨洪水较为频繁，常带来难以计数的伤亡和经济损失。据统计，上世纪90年代开始每年大雨到大暴雨出现的次数在增多，同时福州城市化发展带来的不透水层面积扩大，这两者都对洪水重现期的变化产生较大的影响。为给福州城区的防洪排涝及城市扩展建设提供科学指导，研究洪水重现期的变化有着重要的科学意义。本文旨在研究洪水重现期变化。研究以福州市晋安区八一水库流域为例，按照研究需要将该流域分为A和B两个子流域，借助遥感技术，利用该流域1989、1994、1999、2001、2002、2003、2007年份的TM/ETM+影像获取各年份的土地利用分类情况。结合流域数字高程数据(DEM)，土壤类型数据，以及流域气象、水文资料，应用WMS7.1软件构建流域结构，建立HEC-HMS水文模型对流域内单次降雨的降雨-径流进行模拟。研究比较发现实测径流量与模拟径流量数值较为接近，建立模型模拟结果基本可信。模型模拟结果得到单次降雨和径流在24小时历时内皆呈现正态分布的变化，单次降雨的洪峰到达时间及峰值随年份变化而有不同程度的提前。在降雨—径流的形成理论基础上，结合模型，情景模拟了影响径流的两种情况，得到以下结论：⑴在相同的土地利用情况下，流域内的径流量与峰值都和降雨量呈良好的二次抛物线关系。⑵在相同的降雨强度情况下，流域内的径流量和CN值亦呈良好的二次抛物线关系。降雨—径流的转化过程及所产生洪水的重现期同时受到降雨强度及土地利用两者的作用。本研究通过建立不透水率(Im)与CN值的关系，拟合公式为CN=61.842Im0.0924，构建不透水率与洪水重现期的关系，并将降雨强度及土地利用两大影响因素组合后进行模拟估算，以不透水率和重现期为变量，绘制重现期变化趋势图。由趋势图得出，30年间，A流域重现期为100、50、25年一遇的洪水随着不透水率的增长，分别提前了20年、8年、3年。B流域的重现期为100、50、25年一遇的洪水随着不透水率的增长，分别提前了25年、10年、4年。本研究为洪水重现期的研究积累了宝贵的经验。研究结果有利于城市防洪规划和城市防洪排涝应急方案措施的科学制定，并对城市流域的土地利用合理规划提供了基础理论依据。更多还原

【Abstract】 Flood, which is one of the most critical disasters, is famous for itshigh frequency, wide impact scope and violent oncoming force. Becauseof the typhoon storm flood during rainy season, Fuzhou, located on thesoutheast coast of China, is bearing huge calamities and economic lossannually. According to statistics, the number of heavy rain was risingannually since the1990s. At the same time urbanization processchanged urban land use status and the impervious surface ratios. Both ofthese had influences on the change of return periods. It is vitalimportant to conduct a series of studies on the change of return periods,aiming to provide guidance for flood control under the circumstance ofurban expansion.This study focuses mainly the change in return periods. The BayiReservoir watershed, situated in Jin’an district of Fuzhou city, was takenas an example in this paper. In virtue of remote sensing technology, thelanduse information can be extracted from the TM/ETM+image of studyin1989,1994,1999,2001,2002,2003,2007. Additionally, digitalelevation model (DEM) data, soil type data, meteorological andhydrological data were collected to provide model information in thestudy. The Bayi Reservoir watershed HEC-HMS hydrological modelwas well established after the pretreatment of partial data by means ofWMS software. Furthermore, the process of single rainfall-runoff in theBayi Reservoir watershed was simulated. The simulation results broadlyconsistent with the actual data, and the results are credible.The result indicated that single rainfall and runoff within24hoursboth are normal distribution. The peak time and peak flows of singlerainfall both were ahead of their designed time. Based on the theory ofrainfall-runoff and the HEC-HMS model, this paper used model to carryout two scene simulations, and got some results. The results showed thatin the same landuse, the relationship between runoff and peak flows was quadratic parabola, and in the same rainfall conditions, the relationshipbetween runoff and CN was quadratic parabola.Rainfall conditions and land use both impacted rainfall–runoff andthe return periods. This study found that the relationships between theimpervious surface ratios (Im) and CN was CN=61.842Im0.0924. And itstructured the relationship between the impervious surface ratios and thereturn periods. The study designed to combine the rainfall conditionswith landuse case to calculate the discharge, and used impervious surfaceratios and return periods as the variables, drew the graph of return periodchange. Finally according to the graph, in A sub-basin the returnperiods of100,50,25years were ahead of designed time by20,8,3yearswith the growth of impervious surface ratios. In B sub-basin the returnperiods of100,50,25years were ahead of designed time by25,10,4years.This study provided precious experiences for return periods research.The research results were beneficial to urban flood control planning andscientific establishment of emergency program for urban flood controland drainage, furthermore, the results supplied theoretical basis torational planning for land use in urban watershed and scientificprevention and treatment of non-point pollution.更多还原