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1.
Mountain catchments are prone to flash flooding due to heavy rainfall. Enhanced understanding of the generation and evolution processes of flash floods is essential for effective flood risk management. However, traditional distributed hydrological models based on kinematic and diffusion wave approximations ignore certain physical mechanisms of flash floods and thus bear excessive uncertainty. Here a hydrodynamic model is presented for flash floods based on the full two-dimensional shallow water equations incorporating rainfall and infiltration. Laboratory experiments of overland flows were modelled to illustrate the capability of the model. Then the model was applied to resolve two observed flash floods of distinct magnitudes in the Lengkou catchment in Shanxi Province, China. The present model is shown to be able to reproduce the flood flows fairly well compared to the observed data. The spatial distribution of rainfall is shown to be crucial for the modelling of flash floods. Sensitivity analyses of the model parameters reveal that the stage and discharge hydrographs are more sensitive to the Manning roughness and initial water content in the catchment than to the Green-Ampt head. Most notably, as the flash flood augments due to heavier rainfall, the modelling results agree with observed data better, which clearly characterizes the paramount role of rainfall in dictating the floods. From practical perspectives, the proposed model is more appropriate for modelling large flash floods.  相似文献   

2.
Hydrological models within inflow forecasting systems for high-alpine hydropower reservoirs can provide valuable information as part of a decision support system for the improvement of hydropower production or flood retention. The information, especially concerning runoff, is however rarely available for the calibration of the hydrological models used. Therefore, a method is presented to derive local runoff from secondary information for the calibration of the model parameters of the rainfallrunoff model COSERO. Changes in water levels in reservoirs, reservoir outflows, discharge measurements at water intakes and in transport lines are thereby used to derive the local, “natural” flow for a given sub-catchment. The proposed method is applied within a research study for the ÖBB Infrastructure Railsystem division in the Stubache catchment in the central Austrian Alps. Here, the ÖBB operates the hydropower scheme “Kraftwerksgruppe Stubachtal”, which consists of 7 reservoirs and 4 hydropower stations. The hydrological model has been set up considering this human influences and the high natural heterogeneity in topography and land cover, including glaciers. Overall, the hydrological model performs mostly well for the catchment with highest NSE values of 0.78 for the calibration and 0.79 for the validation period, also considering the use of homogeneous parameter fields and the uncertainty of the derived local discharge values. The derived runoff data proved to be useful information for the model calibration. Further analysis, examining the water balance and its components as well as snow cover, showed satisfactory simulation results. In conclusion, a unique runoff dataset for a small scale high-alpine catchment has been created to establish a hydrological flow prediction model which in a further step can be used for improved and sustainable hydropower management.  相似文献   

3.
基于洪峰模数的山洪灾害雨量预警指标研究   总被引：1，自引：0，他引：1  
山洪灾害预警是防御山洪的重要非工程措施,雨量预警指标是山洪灾害预警的关键。目前的雨量预警指标计算方法对水文气象资料条件以及模型建模率定都有很高的要求,并不适用于基层防汛人员。因此,本文基于全国山洪灾害调查评价成果数据,提出了一种运用洪峰模数计算雨量预警指标的简便、易用的方法。该方法以小流域洪水计算推理公式为基础,将公式中流量与流域面积的比值用洪峰模数表示,得到基于洪峰模数的临界雨量估算公式,并考虑流域土壤含水量等因素,分析临界雨量变化阈值,最终得到雨量预警指标。本文以云南省绥江县双河小流域为例,计算结果显示不同时段（1 h、3 h、6 h）净雨量和预警时段呈线性关系。降雨损失计算中洼地蓄水和植被截留在不同时段相同,土壤下渗在不同的时段不相同。在此基础上,计算不同土壤含水量条件下,不同时段的雨量预警指标。最后,对临界流量、降雨损失和预警指标进行了合理性分析,结果显示预警指标和调查评价结果及实测降雨都比较接近,计算的预警指标合理。本研究为基层山洪灾害预警提供了一种快速、便捷的预警指标计算方法,为预警指标计算提供技术支持。  相似文献   

4.
Land use changes such as deforestation,increase in cropping or grazing areas and built-up land, likely modify the water balance and land surface behavior in the Himalayan watersheds.An integrated approach of hydrological and hydraulic modeling was adopted for comparative analysis of hydrological pattern in three Himalayan watersheds i.e.Khanpur,Rawal and Simly situated in the Northern territory of Pakistan.The rainfall-runoff model SWAT- Soil and water assessment tool and Hydro CAD were calibrated for the selected watersheds.The correlation analysis of the precipitation data of two climate stations i.e.Murree and Islamabad, with the discharge data of three rivers was utilized to select best suitable input precipitation data for Hydro CAD rainfall-runoff modeling.The peak flood hydrograph were generated using Hydro CAD runoff to optimize the basin parameters like CN, runoff volume, peak flows of the three watersheds.The hydrological response of the Rawal watershed was studied as a case study to different scenarios of land use change using SWAT model.The scenario of high deforestation indicated a decline of about 6.3% in the groundwater recharge tostream while increase of 7.1% in the surface runoff has been observed under the scenario of growth in urbanization in the recent decades.The integrated modeling approach proved helpful in investigating the hydrological behavior under changing environment at watershed level in the Himalayan region.  相似文献   

5.
Flashfloodsaretheimportanteventsofthehydrologicalregimeofriversinaridareas.IntheTarilncaver(Fig.1),northwesternChina,flashfledarebeingmonitored.TheobSerVeddataandinvestigationdemonstratethedifferenceintime,place,frequencyandintensityoftheiroccurrences.Therearethreet~offlagescommontotheThermcaverbasin.AlmOSteveryyea-rhighwateroccursinmonthesofJuly,AugUstandseptembercausedbyablationrunoff.However,themostdamagingflowSarefromoccasionalflashfindsbyinstenserainstormandglacierlakeoutburstflags(…  相似文献   

6.
Suspended sediment transport in streams is an effective indicator of soil erosion at the watershed scale. This process was studied using the data obtained from two continuous monitoring stations installed in Italian watersheds, the Rio Cordon and Torrente Carapelle. The catchments have substantially different climatic, morphological and land use characteristics. The Rio Cordon, a small Alpine watershed, has been monitored since 1986, while in the Torrente Carapelle, a medium-size Mediterranean watershed, the monitoring station has provided data since 2007. Several flood events with suspended sediment transport were isolated in the two catchments, excluding those determined by snowmelt in the Rio Cordon as this process does not affect the Carapelle watershed. Analysis of the events showed different behavior in terms of hysteresis loop trends between water discharge (m3 s-1) and suspended sediment concentration (g l-1) values, as the Rio Cordon confirms clockwise relationships most frequently, while counter-clockwise trends represent the majority of cases for the Carapelle Torrent. The different behavior of the two watersheds was further analyzed by evaluating relationships between the main hydrological parameters related to suspended sediment transport. Runoff controls the total sediment budget in both catchments. In contrast, it was noted that the runoff process does not interfere in the magnitude of the suspended sediment transport in the Rio Cordon catchment, while variations due to the larger size of the catchment area characterize the events in the Carapelle watershed. Lastly, a flow peak threshold that determines the advance or delay of the hydrograph peak with respect to the sedigraph peak was established for the Carapelle Torrent, while it was not reported in the Rio Cordon.  相似文献   

7.
洪水研究包括径流与淹没两种模式。为了探究流域降雨产汇流与淹没情况、提高洪水预报精度,本研究在传统流域水文模型的基础上耦合二维水动力学模型,建立水文-水动力耦合模型。以我国吉林温德河流域为研究实例,模拟了2017年“7·13”洪水在下游口前镇所处子流域洪水淹没过程。首先对基础数据进行预处理,建立HEC-HMS水文模型并进行参数优化后,最终获得流量过程水文结果作为水动力学模型边界条件,之后建立HEC-RAS二维水动力学模型对重要子流域进行淹没模拟。耦合模型计算结果显示,水文模型经多参数优化流量模拟的NSE系数为0.988,水动力计算最大淹没水深达9.3 m相对误差为-5.2%。从泛洪模拟结果来看,子流域上游部分的农田大量被淹,淹没水深范围在0.5~2.0 m,平均流速基本在1 m/s以下。下游口前镇内最大淹没水深接近1 m,水流速度0.2 m/s至1.5 m/s,与实际的淹没情况相吻合。研究表明,所建水文水动力耦合模型模拟计算的结果准确率较高,对具有复杂水文、水力条件的流域的洪水预报具有重要的指导意义。  相似文献   

8.
To improve flood control efficiency and increase urban resilience to flooding, the impacts of forest type change on flood control in the upper reach of the Tingjiang River (URTR) were evaluated by a modified model based on the Soil Conservation Service curve number (SCS-CN) method. Parameters of the model were selected and determined according to the comprehensive analysis of model evaluation indexes. The first simulation of forest reconstruction scenario, namely a coniferous forest covering 59.35 km2 is replaced by a broad-leaved forest showed no significant impact on the flood reduction in the URTR. The second simulation was added with 61.75 km2 bamboo forest replaced by broad-leaved forest, the reduction of flood peak discharge and flood volume could be improved significantly. Specifically, flood peak discharge of 10-year return period event was reduced to 7-year event, and the reduction rate of small flood was 21%-28%. Moreover, the flood volume was reduced by 9%-14% and 18%-35% for moderate floods and small floods, respectively. The results suggest that the bamboo forest reconstruction is an effective control solution for small to moderate flood in the URTR, the effect of forest conversion on flood volume is increasingly reduced as the rainfall amount increases to more extreme magnitude. Using a hydrological model with scenarios analysis is an effective simulation approach in investigating the relationship between forest type change and flood control. This method would provide reliable support for flood control and disaster mitigation in mountainous cities.  相似文献   

9.
对河道汇流过程进行模拟可为洪水灾害预警预报提供参考。利用水力水文学方法能很好地模拟河道汇流过程,但需要输入的参数多,运算过程复杂,对数据精度要求高,而且在无资料区流域无法确定河道上断面流量情况下,该方法具有一定局限性。本文将元胞自动机模型与水文模型相结合,构建了河道汇流过程中的元胞自动机模型和产流汇流规则。通过建立河道坡面拓扑关系,利用SCS-CN（Soil Conservation Service-Curve Number）模型逐个计算河道元胞上的坡面入流,并利用曼宁方程模拟河道汇流过程,最后在ArcEngine平台下进行二次开发,实现了河道汇流可视化。本文以厦门市茂林溪流域为研究区,对1997年5月6日至7日的一场降雨进行了模拟。将本文模拟结果与该流域其他学者的研究进行了对比分析,结果表明在输入数据与水文模型参数相同的情况下,本文不仅模拟出每次降雨间隔产生的较小洪峰,并且整场降雨产生的最大洪峰流量精度与时间精度均提高了5倍,可以更准确地模拟河道汇流过程,适用于河道汇流可视化,该模拟可以为洪水灾害预警预报提供一定参考。  相似文献   

10.
基于WebGIS的流域级洪水管理系统集成与应用   总被引：1，自引：0，他引：1  
流域级洪水管理系统指为流域机构服务的洪水管理系统,是基于计算机网络、地理信息系统、数据库技术,专业分析模型,采用人机交互方式,按照统一标准与规范建立的流域洪水管理平台。为洪水预报、预警、预案编制、应急调度、风险评价、洪水整治、决策会商提供先进技术手段。本文首先讨论了流域洪水管理系统的结构设计与数据库,然后,以松花江流域洪水管理系统为例,对系统功能与分析模型进行了讨论。功能模块包括基础信息管理、洪水监视预警、洪水预报调度、二维洪水仿真、灾情评估、防汛管理等功能模块;分析模型方面,建立了水文-水力学耦合模型、全流域洪水预报模型与洪水调度模型。该模型由基于MIKE NAM的全流域降雨径流模型与基于MIKE11 HD的嫩江、二松、松干河道一维水动力模型组成。此外,在哈尔滨等4个重点城市与两个蓄滞洪区构建了MIKE21的二维洪水模拟模型,在城市、蓄滞洪区与防洪重点保护区,建立了灾情影响分析模型等。最后,利用WebGIS技术对这些功能模块进行了集成,建立了功能齐全的松花江流域洪水管理系统。作为国内第一个流域级洪水管理系统,松花江流域洪水管理系统的设计与建设,对流域级洪水管理系统的研究进行了有益的探索。  相似文献   

11.
Concerns regarding urbanization impacts on floods gradually moved from end-of-pipe solutions, based on open channel hydraulics improvement, to imperviousness ratio limiting and then to land use control and to integrated planning at local and large scale levels. The Niushou River basin is one of the fastest urbanizing areas in Nanjing City, East China, however, the high urban land percentage has leaded to series of flooding events. The paper aims to reveal the impact of imperviousness ratio, patterns and drainage system on flooding areas based on the unit of catchment and Storm Water Management Model (SWMM). The following conclusions were reached. 1) The ratio or spatial characteristics of the impervious surface affected the runoff volumes and associated floods areas. Despite the well-established drainage system, the high imperviousness ratio, particularly clustered pattern in locations such as hydrological sensitive zones aggravated the flooding tension across the basin. 2) The poor drainage hydraulic efficiency in local areas, and the lack of integral processes of infiltration, yield, storage and discharge in local catchment and larger basin are also significant factors. 3) The Niushou River basin development should improve the drainage transformations from a single local, short-term drainage process into integral, elastic processes of infiltration, yield, storage, and discharge.  相似文献   

12.
As a major sediment area in the upper Yangtze River, Jialing River basin experienced substantial land-use changes, many water conservancy projects were constructed from the 1980 s onward to promote water and soil conservation. The water and sediment yield at the watershed outlet was strongly affected by these water conservation works, including ponds and reservoirs, which should be considered in the modelling. In this study, based on the observed data of the Weicheng River catchment, the relationships between precipitation, runoff, vegetation, topography and sediment yield were analyzed, a distributed runoff and sediment yield model(WSTD-SED) was developed, and the hydrological processes of different land-use scenarios were simulated by using the model. The main results are summarized as follows: 1) there is an alternating characteristic in river channels and reservoirs in the Jialing River hilly area, with scour occurring in wet years and deposit occurring in dry years. 2) Most of the sediment deposited in river channels and reservoirs is carried off by the largest flood in the year. 3) The model yielded plausible results for runoff and sediment yield dynamics without the need of calibration, and the WSTD-SED model could be usedto obtain qualitative estimates on the effects of land use change scenarios. 4) The modelling results suggest that a 10% increase in cropland(dry land) reforestation results in a 0.7% decrease in runoff and 1.5% decrease in sediment yield.  相似文献   

13.
经典的Vensim模型采用2个平行线性水箱来模拟岩溶水文系统中的慢速流和快速流, 很难模拟岩溶水文系统内的非线性水文过程。提出一种改进的R-Vensim模型, 将Vensim中的一个水箱改为非线性水箱, 同时进一步考虑不同水文条件下降雨分配系数的变化, 用于模拟岩溶含水层中存在的非线性水文过程。2个模型被用于模拟丫吉试验场的S31岩溶泉, 模拟结果表明R-Vensim能更好地模拟不同降雨条件下岩溶泉水文动态过程, 而Vensim总是低估暴雨下的流量峰值和高估低强度降雨下的流量峰值。研究区岩溶水文系统中慢速流呈现强烈的非线性, 而快速流更接近于线性过程, 2个模拟时段内78.5%和68.4%的泉流量来源于非线性水箱。研究结果表明模型中考虑非线性水文过程对于岩溶泉流量尤其低流量过程的精准模拟十分重要。   相似文献   

14.
流域空间离散化及其对径流过程模拟的影响研究   总被引：1，自引：0，他引：1  
本文分析比较了流域空间离散化的两种途径 :子流域法和网格法 ,并以此对流域径流过程模拟的影响进行了探讨。结果表明空间尺度和时间尺度之间应该是相互关联、相互匹配的 ;时空尺度具体大小的选定要根据研究目的、研究区域的面积、流域下扩建面信息源和模型输入资料的可获性综合考虑。  相似文献   

15.
By using a degree-day based distributed hydrological model, regimes of glacial runoff from the Koxkar glacier during 2007-2011 are simulated, and variations and characteristics of major hydrological components are discussed. The results show that the meltwater runoff contributes 67.4%, of the proglacial discharge, out of which snowmelt, clean ice melting, buried-ice ablation and ice-cliff backwasting account for 22.4%, 21.9%, 17.9% and 5.3% of the total melt runoff, respectively. Rainfall runoff is significant in mid-latitude glacierized mountain areas like Tianshan and Karakorum. In the Koxkar glacier catchment, about 11.5% of stream water is initiated from liquid precipitation. Spatial distributions for each glacial runoff component reveal the importance of climatic gradients, local topography and morphology on glacial runoff generation, and temporal variations of these components is closely related to the annual cycle of catchment meteorology and glacier storage. Four stages are recognized in the seasonal variations of glacier storage, reflecting changes in meltwater yields, meteorological conditions and drainage systems in the annual hydrological cycle.  相似文献   

16.
Extreme seasonal water level fluctuations characterize natural floodplain lakes in monsoon regions, which are crucial for ensuring lake water security, including flood prevention water supply and health of aquatic ecosystem. In order to achieve this goal, we established a hydrological regime assessment method based on a set of hydrological indicators for lakes with heavy seasonal water level fluctuations. The results suggest that time-sensitive hydrological indicators and specific time scales for various water security aspects must be considered. We discovered that it is more practical and meaningful to combine the water level classification derived from statistical analyses with characteristic hydrological values linked to water security. The case study of Poyang Lake results show that there are no discernable trends of Poyang Lake water regime status over the last 35 years, and the two periods of poor status are in accordance with climate variation in the lake basin area. Scholars and policy makers should focus on both floods and droughts, which are the main water security problems for Poyang Lake. It is hoped that this multi-scale and multi-element hydrological regime assessment method will provide new guidelines and methods for other international scholars of river and lake water assessment.  相似文献   

17.
汇水区划分是分布式水文模型计算的基础。针对现有方法使用DEM在平原城市地区划分的汇水区不符合实际地形情况,本文提出了一种面向城市平原地区分级划分汇水区的技术方法。该方法从城市用地分类角度出发将城市分为中心城区和郊区,依据城市排水主干水系进行汇水区一级划分,将影响中心城区和郊区的不同径流因子分别融入DEM中,利用细化的DEM进行二级汇水区划分;在此基础上,根据实际汇流情况,结合Voronoi图,对中心城区进行三级划分,最后通过GIS技术进行修正。该方法既结合了传统DEM生成子流域的算法,又融入了城市区域地物地貌特点,能更好地满足城市地区的需要。选择上海市嘉定区西北部地区为实验样区,利用该方法进行汇水区划分比较表明,其对于城市平原地区具有很好的适用性。  相似文献   

18.
The Wenchuan earthquake that occurred on 12 May 2008 induced numerous landslides. Loose landslide materials were deposited on hillslopes, and deep channels were easily remobilized and transformed into debris flows by extreme rainstorms. Twelve years after the Wenchuan earthquake, debris flows were still active in the Qipangou Ravine in the quake-hit area. In this paper, we continuously tracked the spatiotemporal evolution of the landslides and vegetation restoration and evaluated the evolution of debris flow activity in the Qipan catchment with the aid of a GIS platform and field investigations from 2008 to 2019. We observed that the area with active landslides increased sharply immediately following the earthquake, and then decreased with time; however, the total area of landslides continued to increase from 6.93 km2 in 2008 to 10.55 km2 in 2019. The active landslides shifted towards lower angles and higher elevations after 2013. Since 2009, the vegetation coverage has been gradually increasing and approaching the coverage present before the earthquake as of 2019. The landslide activity was high and the vegetation recovery rates were rapidly rising during the first five years after the earthquake; the recovery rates then slowed over time. Therefore, we divided the evolution that occurred during the post landslide period into an active period(2008-2013), a self-adjustment period(2013-2026) and a stable period(after 2026). We then proposed a quantitative model to determine the trends of landslide activity rates and NDVI values in the catchment, which indicated that the landslide activities and postseismic vegetation restoration rates in this catchment will return to preseismic levels within approximately two decades. We also analysed the runout volumes of the debris flows after the earthquakes(Diexi and Wenchuan) and the standard deviation of the vegetation coverage and predicted that the debris flow activities will last for an additional 50 years or more.  相似文献   

19.
In this study, the differences in annual rainstorm changes in the Second Songhua River Basin and the Nenjiang River basin and their causes were compared from the perspective of mountain effects. The following results were drawn: (1) Altitude effect is the primary factor leading to increased rainstorms in the southern source; (2) Slope effect primarily leads to differences of the weather systems in the two sources, and thus cause the difference of the rainstorms; (3) Slope effect is responsible for the greater fluctuation in the observed floods in the southern source. These landform differences eventually lead to the differences in the characteristics of floods in the southern and northern sources. Commensurability method was used to identify the period of rainstorms in the southern and northern sources. The results showed that although rainstorms do not appear at the same time in the two sources they are characteristic of a 10 years’ period in both areas. These results can serve as hydrological references for flood control and long-term flood disaster predictions.  相似文献   

20.
流域水文模型研究的进展   总被引：14，自引：2，他引：12  
流域水文模型是对流域上发生的水文过程进行模拟计算的数学模型 ,在水文过程模拟中 ,对流域内的产流 ,坡面汇流以及河道汇流过程的模拟是很重要的。坡面产汇流模型模拟从降水到流域产流和流域坡面汇流的水文子过程 ,河道演进模型模拟河网汇流水文子过程 ,现有的水文模型大多数是没有考虑水文变量和水文参数空间变化的概念性水文模型。随着地理信息技术的发展 ,考虑水文变量和水文参数空间变化的分布式水文模型得到了极大的重视与发展 ,而且 ,遥感技术的发展满足了分布式水文模型对空间信息的需求.  相似文献   

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