江垭水库洪水单位过程线的推求方法

以江垭水库某次洪水过程为例,探讨了洪水单位过程线的推求。由实际降雨量和流量过程线进行分析,并做了基本假定;所选的降雨洪水过程超过三个时段,且有一个最大值,故采用试错法进行推求,给出了推求过程及方法。将推求成果与降雨径流相关图配合使用,可对洪水过程进行预报。     

流域汇流单位线时段转换应用分析

当流域汛期雨情报讯时段在特殊情况下出现变化时,流域汇流单位线必须事先进行时段转换后才能用于实际洪水预报。以实测水文原始数据为依据,根据示例流域在水文预报工作中的特殊需要,采用s曲线法对流域汇流单位线进行了实例转换和应用分析。分析成果符合相关行业规范精度标准,提出了分析成果的具体使用条件和应用范围,成果能够作为备选方法用于实际工作之中。     

Estimation of the Velocity Parameter of the Geomorphologic Instantaneous Unit Hydrograph

The problem of estimation of the velocity parameter in the exponential distribution geomorphological instantaneous unit hydrograph (ED-GIUH) is investigated in this study. The main difficulty in applying the ED-GIUH model is the estimation of this parameter. In the present study, the ED-GIUH model is applied to six watersheds in Indiana, U.S.A. The relationships between the velocity parameter and climatic as well as basin geomorphologic parameters are investigated. The results of the study indicate that the velocity parameter is related to effective rainfall depth, total basin area and cumulative slope; it does not depend on runoff characteristics. Therefore, the ED-GIUH model can be used for estimating discharge hydrographs from ungauged watersheds.     

Synthetic Unit Hydrograph for Al Fara'a Catchment in the West Bank

Abstract

Synthetic unit hydrographs are frequently used to estimate hydrograph characteristics when observed data are not available. A number of synthetic unit hydrograph approaches are available, but the ones that found widespread use are those based on models of Snyder, Clark, and the U.S. Soil Conservation Services (SCS). The major goal of the study is to develop a synthetic unit hydrograph for Wadi Al Fara'a Catchment, which is un-gauged and considered one of the West Bank's most important catchments. Unfortunately, none of the wadis in the West Bank are gauged and flow records are not available; therefore, it is hoped that this method will be applied successfully for Wadi Al Fara'a catchment and the results can hopefully to be applied to all West Bank catchments, which will facilitate estimation of potential runoff in the whole West Bank.     

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.     

Evaluation of the Adequacy of Statistical Distribution Functions for Deriving Unit Hydrograph

The unit hydrograph (UH) is one of the commonly employed techniques for the determination of flood hydrographs. Since the UH satisfies all the properties of a probability distribution function (PDF), it seems logical that PDFs can be employed for deriving the UH. In practice, the gamma distribution function has been commonly employed to derive the UH. In this paper, Beta (Beta), Exponential (EXP), Gamma (GM), Normal, Lognormal (LN), Weibull (WB), Logistic (LG), Generalized logistic (GLG) and Pearson Type 3 (PT 3) distribution functions were employed for the derivation of UH. Parameters of these distribution functions were estimated using the real coded genetic algorithm optimization technique. These distributions were tested on the 13 watersheds of different characteristics and it was observed that except for the EXP distribution function, most other distribution functions produced UHs which were in satisfactory agreement with observed UHs. However, three-parameter distributions GLG, PT 3 and two parameter LG were not capable of reproducing UHs for large watersheds having drainage areas of 3,360 and 4,300 km². For such large watersheds WB reproduced UHs satisfactorily. Combining the overall performance of the distributions over 13 watersheds, the order of ranking the suitability of distributions were as: GM > PT 3 > Beta ≥ GLG ≥ LN > WB.     

自适应差分进化算法在设计洪水过程线推求中的应用

针对设计洪水过程线分时段同频率放大法中手工修匀的不足,使用基于相似原理建立的一种推求设计洪水过程线优化模型,可以实现洪水过程的自动放大。文章采用自适应差分进化算法求解该模型,实例表明,该模型可以很好地控制设计洪水洪峰和洪量,有效保持了典型洪水模式,避免了人工修匀的任意性和复杂性,同时改进的差分进化算法可以更高效地完成优化过程。     

瞬时单位线汇流参数m1非线性改进方法探讨

针对瞬时单位线计算设计洪水过程中,对单位线汇流参数m1进行非线性改进的运用条件和改进公式中采用的临界雨强等参数的取值等进行探讨.     

Estimation of Sediment Yield for a Rain,Snow and Glacier Fed River in the Western Himalayan Region

Assessment of soil erosion, sediment transport and deposition of sediment in the reservoirs, irrigation and hydropower systems are considered essential for the land and water management. The magnitude of sediment transported by rivers has become a serious concern for the water resources planning. In the present study, an assessment of sediment yield has been made for the Satluj River, which flows through the western Himalayan region. Two approaches have been used for the assessment of sediment yield (i) relationship between suspended sediment load and discharge and (ii) empirical relationship. The first approach was used for Satluj Basin up to Suni (52 983 km²), Kasol (53 768 km²) and also for the intermediate basin between Kasol and Suni (785 km²). The sediment-discharge relationship was developed using daily data for a period of three years (1991–1993) for different basins and was applied for each basin for the years 1994 and 1996 for estimation of sediment yield. The second approach, which gives annual sediment yield, has been used for a small intermediate basin only because of data availability constraints. For estimation of the sediment yield using the empirical relationship, various geographical parameters such as land use, topographical etc. were generated using Geographic Information System (GIS) technique. The annual sediment yield for the intermediate basin was estimated for three years and compared with observed values. The trend of difference between computed and observed sediment yield suggested an effect of physical features of mountainous basins. The available empirical relationship was, therefore, revised by incorporating a basin parameter in the equation. This basin parameter represented an integrated effect of slope and spatial distribution of rainfall in the mountainous basin. Using the revised empirical relationship, the sediment yield was estimated for two independent years and a good correlation was found between computed and observed sediment yield.     

浅谈经验单位线法在岩溶区洪水计算中的应用

由于缺乏实测水文资料,桂北、桂西片区域岩溶地区水利工程设计洪水计算一直都是个难题。介绍了采用经验单位线法计算岩溶地区设计洪水的方法及流程。     

丹竹坪水电站黄沙坝址设计洪水的推求

丹竹坪水电站黄沙坝址设计洪水计算由于流量资料不足,又难以使用相关法来插补延长.只能用暴雨资料来推求工程设计洪水.通过历史洪水调查,分析黄沙河的洪水特性,根据其设计暴雨雨型,经过产流汇流分析计算和实测洪水单位线,采用瞬时单位线、历史洪水经验频率分析等方法,推算出黄沙坝址设计洪水.     

伊洛河夹滩地区对伊洛河入黄洪水的影响

伊洛河河道两岸堤防的存在使夹滩地区的滞洪作用不同于天然滞洪区，它不仅对人黄洪水起滞洪削峰作用，而且对洪水总量还略有削减。不 同时期堤防的建设标准及河道条件不同，夹滩地区的滞洪作用也不同。经过1935、1937、1954、1958、1982年实测洪水资料的分析知，夹滩地区对入黄洪水的滞洪作用与洪水量经大小、洪水过程胖瘦、堤防决溢程度等因素有关，在现状堤防条件下，如何再发生1954、1958年量级的洪水，在确保洛洛北大堤安全的情况下，有计划地使用夹滩及南岸滞洪共滞洪，则夹滩地区对入黄洪水的削峰率可达20%～25%。但夹滩地区的容量有限，因此对洪水总量的滞蓄作用不大。     

Evaluation of three unit hydrograph models to predict the surface runoff from a Canadian watershed

The predictability of unit hydrograph (UH) models that are based on the concepts of land morphology and isochrones to generate direct runoff hydrograph (DRH) were evaluated in this paper. The intention of this study was to evaluate the models for accurate runoff prediction from ungauged watershed using the ArcGIS^® tool. Three models such as exponential distributed geomorphologic instantaneous unit hydrograph (ED-GIUH) model, GIUH based Clark model, and spatially distributed unit hydrograph (SDUH) model, were used to generate the DRHs for the St. Esprit watershed, Quebec, Canada. Predictability of these models was evaluated by comparing the generated DRHs versus the observed DRH at the watershed outlet. The model input data, including natural drainage network and Horton's morphological parameters (e.g. isochrone and instantaneous unit hydrograph), were prepared using a watershed morphological estimation tool (WMET) on ArcGIS^® platform. The isochrone feature class was generated in ArcGIS^® using the time of concentration concepts for overland and channel flow and the instantaneous unit hydrograph was generated using the Clark's reservoir routing and S-hydrograph methods. An accounting procedure was used to estimate UH and DRHs from rainfall events of the watershed. The variable slope method and phi-index method were used for base flow separation and rainfall excess estimation, respectively. It was revealed that the ED-GIUH models performed better for prediction of DRHs for short duration (≤6 h) storm events more accurately (prediction error as low as 4.6–22.8%) for the study watershed, than the GIUH and SDUH models. Thus, facilitated by using ArcGIS^®, the ED-GIUH model could be used as a potential tool to predict DRHs for ungauged watersheds that have similar geomorphology as that of the St. Esprit watershed.     

上游水库调蓄对桂林水文站洪水预报的影响分析

随着上游川江、小溶江及斧子口水库的陆续建成,桂林水文站上游流域产、汇流条件已改变,原有的预报方案已不能满足洪水预报作业要求。为此,结合"2013.05"洪水,采用单位线法推求天然洪水过程,分析了上游水库调蓄对桂林水文站洪水预报的影响,探讨该流域洪水产汇流特性,以期优化桂林水文站洪水预报方案,提高洪水预报精度。     

洪水过程线为五边形的调洪解析计算

中小型水库调洪计算,如果设计洪水过程线为概化五边形模型,则防洪库容和相应的最大下泄流量可通过解析计算求得.推导中先假设洪水来临前库中水位为溢洪堰顶齐平并无闸门控制,为自由溢流,泄流过程线近似为直线.将洪水过程分为三个区,用解析方法建立各区的计算公式.     

澜沧江中游段洪水随机模拟研究

本文分析计算了澜沧江中游段洪水过程随机统计特性，阐述了采用典型解集模型和周期性一阶自回归模型模拟洪水过程情况，取得了比较满意的结果。     

乌溪江流域自动洪水预报系统研究与应用

由于预报模型的局限性和实时信息的不完善,洪水预报过程存在一定误差。利用自动预报模型和人工预报参数交互式修改相结合的方式可提高洪水预报精度。在乌溪江流域自动洪水预报系统研究中,采用径流系数控制前期雨量损失总量,通过调整雨量损失进行产流计算,根据时段降雨的降雨中心和降雨强度选用单位线进行汇流计算。同时在自动化洪水预报基础上配以预报人员的多年预报经验,完成可实时修正、高精度的实时洪水预报。以典型洪水预报为例,人工预报参数交互式修改方法的准确性较高,人工预报峰现时间相差1 h,人工预报洪峰流量误差为0.74%,预报精度等级为乙级。研究成果已在浙江省乌溪江流域自动洪水预报系统得到应用,对其他流域洪水预报具有参考价值。     

引江济汉(项目区)设计洪水计算分析

由于引江济汉工程区域内河流缺乏径流资料,采用暴雨资料来计算设计洪水。经合理性论证后认为,设计暴雨与设计洪水成果合理可靠,满足本阶段引江济汉干渠设计需要。     

红水河与清水河干、支流洪水遭遇分析

以红水河与清水河汇合口迁江镇河段为例,通过分析干流红水河与支流清水河洪水的组合情况,推算受干流红水河顶托影响的支流清水河河口段设计洪水位。河段设计洪水水面线是堤防设计的主要依据,对于有干支流洪水相互顶托的河段,需分析其洪水组合和遭遇规律,进行不同组合情况的水面线推算,以外包线作为设计的依据。     

滦河迁西段设计洪水分析

滦河迁西段河道位于潘家口和大黑汀水库下游,设计洪水需要考虑水库下泄洪水与区间洪水的组合,通过对天然条件和设计条件下的水库及区间洪水组合情况进行分析,得到合理的设计洪水成果,以做为工程设计的依据。