GIS技术在小流域地区暴雨推求设计洪水的应用

广东省小流域地区暴雨推求设计洪水的方法主要是广东省综合单位线法和推理公式法。GIS技术结合DEM和土壤数据的应用为流域地理属性的提取提供了便利,进而为无资料地区设计洪水推求提供基础条件。该文以流溪河水库流域为例,采用STRM90m的DEM和国际粮农组织(FAO)1k分辨率的土壤数据,在ArcGIS9.2平台中分析计算流域地理参数,用以计算该流域地区暴雨推求设计洪水,取得较好的效果。     

资料匮乏地区中小流域设计洪水计算方法的研究

因缺乏实测流量资料,中小流域常采用暴雨资料推求设计洪水。文章以乌托水电站近坝支流--谟章河为例,首先基于数字高程模型（DEM）和ArcGIS平台提取流域特征信息,为谟章河设计洪水推求提供基础条件;然后利用反距离权重插值法计算谟章河流域设计暴雨;接着利用SCS模型进行产流计算,利用推理公式法进行汇流计算。计算结果表明,推荐的中小流域设计洪水计算方法是可行的,对解决资料匮乏地区具有一定的参考价值。     

无资料地区设计洪水计算成果合理性探析

无资料地区设计洪水计算,由于缺乏水文实测资料,成果准确性难以保证。以蓝田县汤峪河流域为例,通过对小流域典型设计洪水流量推求,采用地区经验公式、推理公式等传统计算方法和基于高精度的DEM的分布式水文模型计算方法,对计算成果进行相互对比、与设计流域已有成果和相似流域进行对比、与新方法计算结果进行对比,综合分析其合理性。进而对无资料地区设计洪水计算成果合理性分析及新方法未来发展领域进行探析。     

Wetspa模型在流溪河水库入库洪水模拟中的应用

Wetspa模型是一个基于GIS技术的分布式物理水文模型。引进Wetspa模型,以广东省流溪河水库流域为例,利用流域的DEM、土地利用、土壤等数字化资料, 以ArcView3.2为操作平台,经过模型预处理, 建立了流溪河水库流域的Wetspa模型框架。从流域出口断面1980-2004年的流量资料中选取有代表性的大中小洪水20场,其中15场用来率定参数,另外5场用来验证模拟结果。研究结果表明,Wetspa模型适用于流溪河水库入库洪水的模拟。     

HEC-HMS模型在新疆天山北坡地区设计洪水计算中的应用

以新疆天山北坡的白杨河、木垒河、乌鲁木齐河、大黑沟和开垦河流域为例,构建了各流域的HEC-HMS模型。利用Arc GIS软件,依据数字高程模型(DEM)、土地利用、土壤类型等遥感数据确定HEC-HMS模型产、汇流参数初值,根据设计暴雨资料对各流域设计洪水进行了模拟,采用白杨河、木垒河、乌鲁木齐河、大黑沟和开垦河的流量频率计算值对模型参数进行率定,并用乌鲁木齐河资料进行结果验证。结果表明:HEC-HMS模型计算结果可靠,可应用于新疆天山北坡地区设计洪水计算中。     

某小型水库工程设计洪水分析计算

在水库工程设计中,所属流域内常常无水文实测流量资料,难以用流量资料推求洪水,针对此类地区设计洪水计算问题,以某一小型水库为研究对象,在分析暴雨洪水特性基础上,分别采用暴雨洪水法、水文比拟法、推理公式法推求水库坝址设计洪水,并结合历史洪水调查、地区等值线图综合分析取值,验证设计洪水成果合理性,为水库的建设提供可靠的依据。     

无资料地区混合地貌流域设计洪峰流量计算探讨

目前无资料地区多采用经验公式法或根据暴雨资料推求设计洪水,这些方法的参数或公式多是根据单一下垫面情况分区建立的,对于混合型地貌并不能完全套用。由于所依据资料的可靠程度不同,各方法计算的洪水成果差异也较大,使得无资料混合地貌流域洪水参数选取及洪水量级更难确定。以南川河为例对无资料地区复杂地貌流域的设计洪峰流量计算进行探讨,分析结果表明:根据下垫面情况将流域分为黄土丘陵沟壑区和黄土林区两部分,分别按经验公式法、推理公式法推求各分区设计洪水并进行叠加计算,这样推求的洪峰流量成果更符合流域实际。     

基于HEC-HMS的资料匮乏山区洪水模拟研究

以白花河小流域为例,探讨缺资料地区HEC-HMS模型的适用效果。通过流域DEM等下垫面数据获取流域信息,采用SCS-CN曲线法、SCS单位线法、指数衰退法、马斯京根演算法进行流域产汇流计算及河道洪水演算,构建了HEC-HMS降雨径流模型,结合广东省综合单位线法与推理公式法的结果对模型参数进行率定。结果表明,设计洪水计算结果的误差均小于20%且平均相对误差均小于10%;实测洪水模拟的洪峰流量相对误差小于10%,Nash系数为0.90。HEC-HMS模型进行径流模拟效果较好,可适用于研究区山洪预报。     

分布式洪水预报模型在汾河流域的应用

为提高汾河流域的洪水预报水平,选取了该流域DEM、土壤、土地利用及水文气象资料,基于EasyDHM建立了汾河流域分布式洪水预报模型,并进行参数率定。通过场次洪水对模型验证表明,该模型可以很好地应用于流域水情形势分析,从而为流域防洪调度工作的数字化提供技术支持。     

基于推理公式法的小流域牛顿迭代计算程序与流域参数影响分析

由于缺乏流量资料,工程小流域设计洪水计算通常需要采用暴雨资料推求法获得相应的洪峰流量。该文基于推理公式法,结合牛顿迭代方法,基于VC++编译平台自主开发小流域设计洪水计算程序,用于快速计算小流域洪峰流量、汇流历时与汇流速度,提高工程小流域设计洪水计算效率。利用该程序计算小流域河道平均坡降、主河道长及流域下垫面条件类别等参数变化实例,分析参数变化对小流域洪峰流量的影响,对揭示小流域设计洪水的影响因素具有借鉴作用。     

WetSpa Model Application for Assessing Reforestation Impacts on Floods in Margecany–Hornad Watershed,Slovakia

The spatially distributed hydrologic model WetSpa working on a daily or hourly time scale combines elevation, soil and landuse data within GIS, to predict flood hydrographs and spatial distribution of hydrologic characteristics in a watershed. The model is applied to the Margecany–Hornad river basin (1,131 km²) located in Slovakia. Daily hydrometeorological data from 1991 to 2000, including precipitation data from nine stations, temperature data from four stations and evaporation data measured at one station are used as input to the model. Three base maps, i.e., DEM, landuse and soil types are prepared in GIS form, using 100×100 m cell size. Results of the simulations show good agreement between calculated and measured hydrographs at the outlet of the basin. The model predicts the daily/hourly hydrographs with good accuracy, between 75–80% according to the Nash–Sutcliff criteria. For assessing the impact of forests on floods, the calibrated model is applied for a reforestation scenario using the hourly data of the summer of 2001. The scenario considers a 50% increase of forest areas. The model results show that the reforestation scenario decreases the peak discharge by 12%. Investigation of peak discharges from the whole simulation period, shows that the scenario results are reduced by 18% on average. Also, the time to peak of the simulated hydrograph of the reforestation scenario is 14 h longer than for the present landuse. The results show that the effect of land cover on flood is strongly related to storm characteristics and antecedent soil moisture.     

Application of WetSpa model for assessing land use impacts on floods in the Margecany-Hornad watershed, Slovakia.

The spatially distributed hydrologic model WetSpa combines elevation, soil and land use data within GIS, to predict flood hydrographs and spatial distribution of hydrologic characteristics in a watershed. The model is applied to the Margecany-Hornad river basin (1131 km2) in Slovakia. Daily hydrometeorological data from 1991-2000, including precipitation data from nine stations, temperature data from four stations and evaporation data measured at one station are used as input to the model. Three base maps, i.e. DEM, land use and soil type are prepared in GIS form, using 100 x 100 m cell size. Results of the simulations show good agreement between calculated and measured hydrographs. The model predicts the daily/hourly hydrographs with 75-80% accuracy according to the Nash-Sutcliff criteria. For assessing the impact of land use changes on floods, the calibrated model is applied for a reforestation scenario, which considers a 50% increase of forest areas. The model results show that the reforestation scenario decreases the peak discharge by 12%. Investigation of peak discharges from the whole simulation period, shows that the scenario results are reduced by 18% on average, while for small discharges the reduction is even about 34%. The time to peak of the simulated hydrograph of the reforestation scenario is 20 hours longer than for the present land use.     

Flood Modeling for Complex Terrain Using GIS and Remote Sensed Information

A spatially distributed hydrological model WetSpa (Water and Energy Transfer between Soil, Plants and Atmosphere) working on an hourly time scale is presented in this paper. The model combines elevation, soil and land use data, and predicts flood hydrograph and the spatial distribution of hydrological characteristics in a watershed. The model is tested on a small catchment in Belgium for which topography and soil data are available in GIS form, while the land use and soil cover is obtained from remote sensed images. The resulting calculated discharges compare favorably with the field measurements. Next a 102-year series of measured hourly precipitation data is processed with the model and the resulting hydrographs are analyzed statistically to determine the characteristics of extreme floods. Finally, the simulated extreme peak discharges are compared to the results calculated with design storms. Comparison of the two methods shows that the model is capable to predict both normal and extreme floods. Since the model accounts for spatially distributed hydrological and geophysical characteristics of the catchment, it is suitable for simulating hydrological processes in a complex terrain and for predicting the influence of changes in land use on the hydrological behavior of a river basin.     

模型选择准则在洪水频率分析中的应用

以广东省北江流域的长坝、坪石、犁市、韶关4站以及韩江流域的溪口站和珠江三角洲的流溪河站的洪峰流量频率分析为背景,选用6种常用的频率分布线型(模型)进行分析计算,采用线性矩法估计出模型的参数,分别用较少用于水文的模型选择准则AIC、AICc、BIC和ADC进行考虑历史洪水的频率分布模型的选择。结果表明:4种不同模型选择准则对同一站的洪水洪峰流量频率分布线型的选择结果基本一致,与实际资料拟合较好。6站选择的最优线型虽然传统的皮尔逊3型比较多,但最多的是LN型。     

Distributed Hydrological Modeling and Sensitivity Analysis in Torysa Watershed, Slovakia

The spatially distributed hydrologic model WetSpa is applied to the Torysa river basin (1,297 km²) located in Slovakia. Daily hydrometeorological data from 1991 to 2000 are used as input to the model. The spatial characteristic of the basin are described by three base maps, i.e. DEM, landuse and soil type, in GIS form using 100 m cell size. Results of the simulations show a good agreement between calculated and measured hydrographs at the outlet of the basin. The model predicts the daily discharge values with a good accuracy, i.e. about 73% according to the Nash–Sutcliff criterion. Sensitivity analysis of the model parameters is performed using a model-independent parameter estimator, PEST. It is found that the correction factor for calculating the actual evapotranspiration from potential evaporation has the highest relative sensitivity. Parameter K _gm which controls the amount of evapotranspiration from the groundwater has the least relative sensitivity.     

DEM分辨率对小流域设计洪峰推求误差的影响

推理公式法在小流域设计洪水的计算中被广泛应用,DEM数据分辨率对公式中的流域地形参数取值存在重要影响,甚至会造成设计洪峰流量的计算误差。以深圳石岩流域作为研究区域,分别采用分辨率为30,60,90,120,150 m的DEM数据进行流域地形参数的提取及比较分析,并针对推理公式中的3个流域地形参数进行敏感性分析。研究结果表明:随着DEM分辨率的增大,分析的流域面积有增大趋势,主河道坡降则反之,而干流河长随DEM分辨率呈无规律变化;3个流域地形参数中,流域面积取值误差对设计洪峰计算精度影响最大,其次为干流河长,主河道坡降影响较小。综合考虑参数重要性,以及DEM数据分辨率及集水面积阈值对参数取值的影响,选用90 m分辨率的DEM数据,并设置集水面积阈值为390~500 hm~2来提取石岩流域的地形参数,推理公式计算所得设计洪峰误差是可接受的。研究结果可为类似的小流域设计洪水计算提供一定参考。     

基于分布式水文模型的“尼伯特”台风暴雨洪水反演

台风暴雨具有强度大、降雨集中的特点,容易在沿海地区中小流域形成局地破坏性洪水灾害,基于高精度地形地貌数据构建分布式水文模型,是实现中小流域洪水模拟和预报的重要手段。以福建闽清县梅溪流域为研究区,基于高精度DEM、土壤和土地利用数据,采用中国山洪水文模型(CNFF-HM),构建了梅溪流域分布式水文模型,以56场实测水文气象资料对模型进行率定和验证,并对2016年7月9日发生的"尼伯特"台风带来的暴雨洪水进行反演。结果显示,构建的分布式水文模型验证和率定效果良好,对"尼伯特"台风暴雨洪水模拟的洪峰流量误差小于20%,确定性系数达到0.96,因此模型能够很好地反映流域短历时强降雨引发的洪水特征,为流域防洪减灾提供可靠的技术支撑。     

HEC-HMS模型在缺资料地区山洪预报的应用研究

以桃河阳泉小流域为例,探索了HEC-HMS模型在缺资料地区山洪预报的应用可行性。产流模块采用Green-Ampt模型、坡面汇流模块采用SCS单位线、河道汇流模块采用运动波,通过流域DEM、土壤、土地利用等下垫面信息获取了主要参数,构建了山洪预报模型。在1970—2015年的流量系列中筛选出14场典型洪水场次,对模型进行了验证。结果表明,验证期洪峰流量相对误差均小于10%,平均纳什效率为0.88,对于起涨和退水速度快的单峰型洪水,模拟效果较好,通过下垫面信息获取的模型参数准确有效,达到了山洪预报的技术要求。