分布式单位线在河北雨洪模型中的应用

因河北雨洪模型的汇流计算方法难以用于无资料流域,其汇流参数难以获得且不宜移用,为此,将基于数字高程模型的分布式单位线用于河北雨洪模型,并对峪门口流域4场较大洪水过程进行了模拟。结果表明:4场洪水洪峰流量相对误差均<5%,峰现时间误差均<2 h,确定性系数均>0.85,模拟效果令人满意。河北雨洪模型与基于流域地形地貌特征的分布式单位线相结合,可解决无资料流域,特别是山丘地区中小流域的洪灾预警预报等问题。     

分流量区间BMA方法在小流域暴雨山洪模拟中的应用——以官山小流域为例

小流域山洪灾害具有成灾时间短、突发性强、危害性大、频次多等特点,严重威胁着区域内社会经济发展和人民群众生命财产安全。受当前山区雨洪资料少、产汇流机理不够完善所限,小流域的暴雨洪水模拟存在着可靠性差、精度低的问题。以我国中部秦巴山区山洪灾害典型流域官山小流域为研究对象,搜集了近期代表性较好的10场洪水,以TOPMODEL、TUWMODEL和新安江模型结果为基础,基于分流量区间BMA方法计算模型权重,提出适用于小流域的水文集合预报模型。结果显示,相比单一水文模型,分流量区间BMA方法模拟的洪峰流量、洪量和峰现时间指标的合格率可分别提高4.5%、39.7%和48.9%,为官山小流域洪水模拟提供了一种有效的模拟手段。研究成果对提高山区小流域洪水预报精度具有一定的理论意义和实践价值。     

湖北省小流域洪水汇流参数复合分析

基于同一小流域各场洪水的汇流参数,即纳希瞬时单位线(IUH)参数(n、k)随造峰雨强度及时空分布呈一定规律变化的特点,根据湖北境内河流、湖泊、水库实测暴雨洪水资料复合场次洪水汇流参数,综合得出设计条件下的流域汇流参数。结果表明,复合计算洪水与实测洪水较为接近,其复合优化参数明显优于矩法参数,是适用于目前湖北地区洪水资料短缺的小流域设计洪水计算的有效方法之一。     

小流域设计洪水推理公式计算方法探讨

在小文分析计算中，根据现行水利水电工程设计洪水计算规范，小流域暴雨洪水多采用水科院陈家琦的推理公式计算，在公式求解时一般用图解法，亦有采用简单迭代求解。根据在实际中应用推理公式计算小流域设计洪水的工作经验，对其中求解洪峰流量Ｑｍ和汇流时间τ的计算方法采用牛顿迭代法进行适当的优化处理，并以实例说明使用该方法可提高计算速度和成果质量。     

灰关联分析方法在NAM模型参数敏感性分析中的应用

应用NAM模型对资水水系夫夷水流域新宁水文站的洪水过程进行模拟。利用灰色系统关联分析方法来研究NAM模型参数对模型模拟径流深、洪峰流量和峰现时间的影响。计算实例表明：浅层蓄水容量对NAM模型模拟径流深的影响较大,地表径流和壤中流汇流时间常数对NAM模型模拟径流深的影响较小;地表径流系数、地表径流和壤中流汇流时间常数对NAM模型模拟洪峰流量的影响较大,壤中流出流时间对NAM模型模拟洪峰流量的影响较小;地表径流和壤中流汇流时间常数对NAM模型模拟峰现时间的影响较大。     

城镇小流域设计洪峰流量计算方法研究

城镇小流域地处城市化发展快速地区,设计洪峰流量是确定城镇防洪安全的重要依据。阐述了广泛应用于城镇小流域设计洪水计算的综合单位线、推理公式、城市水文学和室外排水公式等方法的基本原理,分别利用这4种方法计算深圳市民治河流域设计洪峰流量。结果表明:尽管不同方法所得结果有一定差异,但综合单位线法与其他方法所得结果的相对误差均在允许范围内,采用综合单位线法所得结果作为设计成果能够满足城市防洪安全。     

推理公式简析法在小流域暴雨洪水计算中的应用

从推理公式的原理和基本关系式出发，导出推理公式在全面汇流时设计洪峰流量的简析式。黄山地区小流域设计洪水计算实例表明，推理公式简析法比图解试算法计算方便， 计算结果与图解试算法计算结果相差小于2.0％。该方法在黄山地区小流域暴雨洪水计算中已得到应用。     

聊城市城区小流域设计洪水分析

对聊城市基于设计暴雨和推理公式计算小流域设计洪水洪峰流量的有关参数进行了分析.结果表明:汇水面积为5 km2时、汇流历时为11.6 h,汇水面积为150 km2时、汇流历时为26.2 h;市区径流系数为0.85～0.70,市郊为0.55;保证率为2%时,最大1 h降水量为120.7 mm,暴雨指数为0.79.同时,得到了各控制断面50 a一遇洪水时的水位和流量.     

HEC-HMS水文模型在辽宁省细河流域的应用研究

基于HEC-HMS模型及地理信息系统平台,对辽宁省细河流域分辨率为90 m×90 m的数字高程数据进行预处理和基本计算,提取研究区水网并划分子流域,收集流域范围内土地利用及土壤类型信息,生成水文模拟基本计算单元。构建两套洪水演算方案对洪水过程进行模拟,方案1采用初损后损法、Snyder单位线法、退水曲线法和马斯京根法;方案2选用SCS曲线法、SCS单位线法、退水曲线法、马斯京根法,并根据实测数据对两种方案结果进行对比验证,以期提高细河流域山洪预报工作准确度。结果显示:方案1模拟结果更适用于细河流域实际的山洪预报工作,洪峰流量和径流深合格率分别为91.67%、100%,确定性系数均值0.79;方案2洪峰流量误差为91.67%,径流深误差合格率为83.33%,峰现时差在两场洪水预测中出现较大偏差,平均确定性系数为0.75;方案1中超渗产流计算方法在细河流域更加适用,模拟误差相对较小;两种方案在短时间强降水洪水汇流计算结果上更加精准。该研究成果可为山区小流域洪水灾害非工程设施建设及产汇流模拟提供一定理论依据和方法支撑。     

HEC-HMS模型在岢岚流域的应用研究

针对岢岚流域1967—2007年的场次洪水情况,在基于DEM构建数字模型的基础上,采用HEC-HMS模型,选取SCS-CN值法、SCS单位线法、指数衰退法以及马斯京根法分别对流域产流、坡面汇流、基流以及河道汇流进行计算,进而构建洪水预报模型,并对模型的适用性进行研究。结果表明：率定期与验证期各场次洪水的洪峰流量、峰现时间以及径流深均达到合格水平,确定性系数DC均值分别为0.640、0.612,合格率均为71.4%,均达到乙级预报精度,且模型对小型洪水的模拟精度较大中型洪水更高;HEC-HMS模型在岢岚流域的适用性良好,能为岢岚流域未来洪水预报提供新的依据。     

Comparing Three Hydrological Models for Flash Flood Simulations in 13 Humid and Semi-humid Mountainous Catchments

Flash flood disaster ranks top among all the natural hazards across the world due to its high frequency, severity and fatality. However, flash flood simulation is still challenging in small and medium-sized catchments with complex orography, flashy hydrological responses and poor observations. Three distributed hydrological models, i.e., TOPModel, HEC and CNFF, are selected to simulate flash floods in seven humid and six semi-humid catchments in China, with consideration of water balance (RER), peak flow rate (REQ) and its occurrence time (TP), hydrograph variation (SNSE) and model uncertainty. Influences of five catchment attributes are further investigated on individual model performances. All three models perform satisfactorily in humid catchments, but less satisfactorily in semi-humid catchments. Water balance is well obtained by CNFF, followed by HEC and TOPModel. Peak flow rate and its occurrence time are most accurately captured by CNFF and HEC, respectively. Hydrograph variations are well reproduced by HEC and CNFF. TOPModel performs well for picking peak flow and hydrograph variation in humid catchments. Uncertainty interval is narrowest for HEC with average relative interval length at 95% confidence level being 0.78?~?2.53. Most observations are bracketed by uncertainty intervals for TOPModel (64.79%?~?91.91% of total). Three model performance indices (i.e., RER, REQ, and SNSE) are mainly affected by drainage area and forest ratio across humid and semi-humid catchments, while TP performance is mainly affected by mean slope in humid catchments.

     

Overland Flow on a Pervious Surface

ABSTRACT

This article presents the analytical solutions for overland runoff hydrographs produced by a uniform rainfall with decay soil infiltration rates. It was found that the kinematic wave travel time through a catchment under such a nonuniform rainfall excess is not a constant, but varies between the time of concentration and the time of equilibrium according to the soil moisture condition. The analytical solutions reveal that kinematic wave travel times are part of the hydrograph convolution process and can hardly be measured from observed hydrographs. The findings of this article suggest that the time of concentration of a small catchment shall be estimated by velocity-based methods rather than those empirical formulas developed for and calibrated by the time difference between the center of mass of the rainfall excess and the inflection point on recession of the observed runoff hydrograph.     

泥沙源区沟道输沙能力的计算方法

小流域沟道是泥沙进入江河的初级通道，在洪水流量较大时，沟道挟沙力强，其输沙量往往接近断面以上流域侵蚀量，进入江河的沙量取决于流域内的补给沙量，但在洪水流量较小时，沟道水流挟沙力下降，其输沙量小于断面以上流域侵蚀量，进入江河的沙量取决于各级沟道的挟沙能力。黄土地区小流域沟道纵坡陡，固体物质补给又十分丰富，虽然沟道尺度不大，但水流含沙量却很高，已有各种基于低含沙水流的挟沙公式不能表达沟道中高含沙水流的输沙特性。作者通过分析及试验研究，求得在输沙平衡条件下水流泥沙因子间的关系，提出小流域沟道挟沙力公式，经初步验证结果满意，这为估算分析不同条件下流域输沙量提供依据，也对水土保持规划有一定的指导意义。     

Sensitivity Analysis of the GIUH based Clark Model for a Catchment

For estimation of runoff response of an ungauged catchment resulting from a rainfall event, geomorphologicalinstantaneous unit hydrograph (GIUH) approach is getting popularbecause of its direct application to an ungauged catchment. Itavoids adoption of tedious methods of regionalization of unithydrograph; wherein, the historical rainfall-runoff data of anumber of gauged catchments are required to be analyzed. In thisstudy, the GIUH derived from geomorphological characteristics ofa catchment has been related to the parameters of Clark IUH modelfor deriving its complete shape. The DSRO hydrographs estimatedby the GIUH based Clark model have been compared with the DSROhydrographs computed by the Clark IUH model option of the HEC-1package and the Nash IUH model by employing some of the commonlyused error functions. Sensitivity analysis of the GIUH basedClark model has been conducted with the objective to identify thegeomorphological and other model parameters which are moresensitive in estimation of peak of unit hydrographs computed bythe GIUH based Clark model. So that these parameters may beevaluated with more precision for accurate estimation of floodhydrographs for the ungauged catchments.     

淤地坝淤积对漫顶溃坝洪水影响数值模拟研究

为分析淤地坝淤积高度对漫顶溃坝洪水的影响,选择理想沟道和某小流域内的淤地坝为研究对象,采用耦合溃口演变过程的水动力数值模型,模拟分析了不同淤积程度下淤地坝溃坝洪水过程。研究表明:溃坝洪水流量随淤积高度的增加而减小,且洪峰流量与淤积高度的关系可用二次多项式拟合,相关系数均在0. 99左右,拟合精度较高;淤积高度至坝高20%和40%时,洪峰流量削减率分别达40. 50%和68. 71%,可见在淤地坝运行初期和中期,淤积对洪峰流量的削减效果显著。研究成果对淤地坝系规划及安全度汛有指导意义。     

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.     

Assessment of flood regulation service based on source–sink landscape analysis in urbanized watershed

Facing climate change and rapid urbanization, urban flooding has exposed human and properties to increasing disaster risks. The attention from researchers and decision-makers to understand the key role of flood regulation service (FRS) in flood management has arisen. However, the mechanism of FRS supply–demand is little known from landscape scale. The FRS assessment methodology considering interacts between source, sink, and flow landscape was proposed in this study. The spatial distributions of surface runoff generation, runoff reduction capacity, and flood inundation were mapped using one-dimensional rainfall–runoff method SCS-CN and two-dimensional flood propagation model CADDIES. Four 3-hour designed rainfall scenarios ranging from nuisance to extreme events (3a, 11a, 56a, and 100a) were simulated. The Liuyang River Watershed in Changsha Municipality, China was selected for case study. The results showed that, the differences of runoff reduction coefficient and runoff generation volume between vegetation and built-up landscape have shortened. The peak flood depth, extent of flood inundation, and peak flood velocity have increased continuously with the growing rainfall intensity. The number of source–sink mismatch catchment was the highest under 56 and 100a, and the most of source-sink match catchments were observed under 3a. Under four rainfall scenarios, the changes of source–sink relationships were witnessed and the potentials of flow zone in source–sink mismatch catchments have increased. The FRS management framework concerning supply–demand connections has been proposed based on source–sink–flow analysis. These findings could provide a scientific basis for sustainable urban flood management and disaster risk mitigation.     

河道数据对流溪河模型预报中小河流洪水的影响

针对琴江流域构建了中小河流洪水预报流溪河模型,分别从河道断面形状、断面尺寸和河道分级的角度定量评估了河道特征数据对应用流溪河模型开展中小河流洪水预报的影响。结果表明:河道分级越多,模型模拟洪水的洪峰流量峰值越大、次洪径流系数越大、洪峰出现时间越早,模拟的洪水过程效果越好;在构建流溪河模型时,假定河道断面为矩形,采用卫星遥感影像估算河道断面尺寸的方法是可行的,模型模拟的洪水过程精度可以满足实际洪水预报的精度要求;利用改进的流溪河模型进行中小河流洪水预报时,以3级河道构建的模型洪水模拟精度最好,可很好地模拟中小河流洪水过程。     

数字水系分级对流溪河模型中小河流洪水预报的影响

为了探讨流溪河模型在中小河流洪水预报中的适用性,以及基于DEM的数字水系提取和分级对流域洪水预报的影响,构建了江西省龙华江流域洪水预报流溪河模型,采用PSO算法优选模型参数,最后验证模型并讨论了数字水系分级对流域洪水预报的影响。结果表明:随着数字水系分级变多,流域洪水峰值增大、峰现时间提前、径流系数越大、模拟过程越接近实测值;采用流溪河模型进行中小河流洪水预报时,不能采用1级数字水系构建模型,适宜采用3级水系构建模型;流溪河模型采用PSO算法的自动优选模型参数,实际应用中只需要一场具有代表性的实测洪水过程就可以优选模型参数,有效提高了模型的性能;基于3级水系构建龙华江流域洪水预报流溪河模型,采用PSO算法优选模型参数,对50场洪水过程的模拟结果与实测值吻合很好,模型可用于龙华江流域实时洪水预报。