Development and Application of a Distributed Conceptual Hydrological Model to Simulate Runoff in the Be River Basin and the Water Transfer Capacity to the Saigon River Basin,Vietnam

A distributed conceptual model(FRASC(Flow Routed Accumulation Simulation in a Catchment))has been developed,in which a rainfall-runoff module is modified from an original lumped conceptual model(Xinanjiang)via a GIS(Geographic Information System)-aided approach and a water allocation module contains reservoirs,water users and hydropower plants.The model is relatively easy to use and can easily obtain input data,but still has the ability to generate hydrological information at many points within a catchment.The model application to the Be River basin is evaluated and shows to be reliable in terms of close agreements between simulated and observed series.Daily natural flow rates for 36 years are simulated at 7,981 grid cells within a studied area of 7,650 km^2.Based on this simulated database,design discharges are predicted in various probabilities.Finally,the research determines that the water transfer capacity from the Be River basin to the Saigon River basin reaches 14%,18% and 23% of a planned value of 75 m^3/s during the dry period in a wet year(P10%),average year(P50%)and dry year(P90%),respectively.

Digital Elevation Modeling不确定性对地形参数影响的空间分布特征分析

Digital elevation modeling(DEM)是基础地理数据之一,从其中可以提取多种地形参数,DEM不确定性对提取的地形参数具有一定的影响.选择坡度、上坡集水面积和地形指数作为研究对象,在DEM不确定性模拟的基础上,研究DEM不确定性对地形参数影响的空间分布特征.研究发现:DEM不确定性对坡度的影响没有明显的空间分布特征,对上坡集水面积和地形指数具有明显的空间分布特征.DEM不确定性对上坡集水面积影响的空间分布特征为:总体上分布均匀,在河道及附近、水库区域影响大于其它地区;DEM不确定性对地形指数影响的空间分布特征为:总体上分布均匀,在河道及附近、水库、平地地区影响大于其它地区.不同DEM不确定性程度对地形参数影响的空间分布特征相似.

Distributed modeling of direct solar radiation on rugged terrain of the Yellow River Basin

Due to the influences of local topographical factors and terrain inter-shielding, calculation of direct solar radiation （DSR） quantity of rugged terrain is very complex. Based on digital elevation model （DEM） data and meteorological observations, a distributed model for calculating DSR over rugged terrain is developed. This model gives an all-sided consideration on factors influencing th a resolution of 1 km × 1 km for thDSR. Using the developed model, normals of annual DSR quantity wie Yellow River Basin was generated, with DEM data as the general characterization of terrain. Characteristics of DSR quantity influenced by geographic and topographic factors over rugged terrain were analyzed thoroughly. Results suggest that： influenced by local topographic factors, i.e. azimuth, slope and so on, and annual DSR quantity over mountainous area has a clear spatial difference; annual DSR quantity of sunny slope （or southern slope） of mountains is obviously larger than that of shady slope （or northern slope）. The calculated DSR quantity of the Yellow River Basin is provided in the same way as other kinds of spatial information and can be employed as basic geographic data for relevant studies as well.

Application of Developed Grid-GA Distributed Hydrologic Model in Semi-Humid and Semi-Arid Basin

A grid and Green-Ampt based （Grid-GA）distributed hydrologic physical model was developed for flood simulation and forecasting in semi-humid and semi-arid basin. Based on topographical information of each grid cell extracted fi＇om the digital elevation model （DEM） and Green-Ampt infiltration method, the Grid-GA model takes into consideration the redistribution of water content, and consists of vegetation and root interception, evapotranspiration, runoff generation via the excess infiltration mechanism, runoff concentration, and flow routing. The downslope redis- tribution of soil moisture is explicitly calculated on a grid basis, and water exchange among grids within runoff routing along the river drainage networks is taken into consideration. The proposed model and Xin＇anjiang model were ap- plied to the upper Lushi basin in the Luohe River, a tributary of the Yellow River, with an area of 4 716 km2 for flood simulation. Results show that both models perform well in flood simulation and can be used for flood forecasting in semi-humid and semi-arid region.

LAN Tool: A GIS Tool for the Improvement of Digital Elevation Models Using Drainage Network Attributes

Digital Elevation Models (DEMs) are constructed using altitude point data and various interpolation techniques. The quality and accuracy of DEMs depend on data point density and the interpolation technique used. Usually however, altitude point data especially in plain areas do not provide realistic DEMs, mainly due to errors produced as a result of the interpolation technique, resulting in imprecise topographic representation of the landscape. Such inconsistencies, which are mainly in the form of surface depressions, are especially crucial when DEMs are used as input to hydrologic modeling for impact studies, as they have a negative impact on the model’s performance. This study presents a Geographical Information System (GIS) tool, named LAN (Line Attribute Network), for the improvement of DEM construction techniques and their spatial accuracy, using drainage network attributes. The developed tool does not alter the interpolation technique, but provides higher point density in areas where most DEM problems occur, such as lowland areas or places where artificial topographic features exist. Application of the LAN tool in two test sites showed that it provides considerable DEM improvement.

Adistributedeco-hydrologicalmodelanditsapplication

Eco-hydrological processes in arid areas are the focus of many hydrological and water resources studies. However, the hydrological cycle and the ecological system have usually been considered separately in most previous studies, and the correlation between the two has not been fully understood. Interdisciplinary research on eco-hydrological processes using multidisciplinary knowledge has been insufficient. In order to quantitatively analyze and evaluate the interaction between the ecosystem and the hydrological cycle, a new kind of eco-hydrological model, the ecology module for a grid-based integrated surface and groundwater model(Eco-GISMOD), is proposed with a two-way coupling approach,which combines the ecological model(EPIC) and hydrological model(GISMOD) by considering water exchange in the soil layer. Water interaction between different soil layers is simply described through a generalized physical process in various situations. A special method was used to simulate the water exchange between plants and the soil layer, taking into account precipitation, evapotranspiration, infiltration, soil water replenishment, and root water uptake. In order to evaluate the system performance, the Heihe River Basin in northwestern China was selected for a case study. The results show that forests and crops were generally growing well with sufficient water supply, but water shortages,especially in the summer, inhibited the growth of grass and caused grass degradation. This demonstrates that water requirements and water consumption for different kinds of vegetation can be estimated by considering the water-supply rules of Eco-GISMOD, which will be helpful for the planning and management of water resources in the future.

Application of Radar-Measured Rain Data in Hydrological Processes Modeling during the Intensified Observation Period of HUBEX

On the basis of Digital Elevation Model data, the raster flow vectors, watershed delineation, and spatial topological relationship are generated by the Martz and Garbrecht method for the upper area of Huangnizhuang station in the Shihe Catchment with 805 km2 of area, an intensified observation field for the HUBEX/GAME Project. Then, the Xin’anjiang Model is applied for runoff production in each grid element where rain data measured by radar at Fuyang station is utilized as the input of the hydrological model. The elements are connected by flow vectors to the outlet of the drainage catchment where runoff is routed by the Muskingum method from each grid element to the outlet according to the length between each grid and the outlet. The Nash-Sutcliffe model efficiency coefficient is 92.41% from 31 May to 3 August 1998, and 85.64%, 86.62%, 92.57%, and 83.91%, respectively for the 1st, 2nd, 3rd, and 4th flood events during the whole computational period. As compared with the case where rain-gauge data are used in simulating the hourly hydrograph at Huangnizhuang station in the Shihe Catchment, the index of model efficiency improvement is positive, ranging from 27.56% to 69.39%. This justifies the claim that radar-measured data are superior to rain-gauge data as inputs to hydrological modeling. As a result, the grid-based hydrological model provides a good platform for runoff computation when radar-measured rain data with highly spatiotemporal resolution are taken as the input of the hydrological model.

GTOPMODEL模型与TOPMODEL模型比较

构造了名为GTOPMODEL用于洪水模拟基于栅格的分布式水文模型.通过假设土壤饱和水力传导率随着深度的增加呈指数递减和地下水面平行于地表面,推导出了基本方程;介绍了植物及根系截留、蒸散发、地下水补给、基流以及汇流的计算方法,并与TOPMODEL进行了比较.采用因特网提供的数字高程模型、土壤组成和土地覆盖等资料,选用流域面积4 716 km2的黄河支流洛河卢氏以上流域,应用两个模型进行了洪水模拟比较.结果表明,在该流域GTOPMODEL比TOPMODEL模拟更好.

基于TOPMODEL的分布式水文模型在中小流域的应用研究

及时准确的洪水预报可为防汛减灾、洪水风险评估、水资源调配管理等方面提供重要的理论指导和决策依据.本文根据TOPMODEL和一维水动力学原理,构建了一套适用于中小流域的松散型分布式水文模型,筛选了40场代表性洪水,对模型的模拟精度进行了评价.结果表明:所有场次洪水模拟结果的峰现时间误差绝对值合格率为97.5%、达到甲级预报精度,洪峰相对误差合格率为75%、达到乙级预报精度,效率系数合格率为77.5%、可达乙级预报精度.本文构建的松散型分布式水文模型,模型参数少、运算速度快且具有较强的物理机制,可为分布式水文模型在实时洪水预报领域的应用提供一条新思路.

Hydrological assessment of TRMM rainfall data over Yangtze River Basin

High-quality rainfall information is critical for accurate simulation of runoff and water cycle processes on the land surface. In situ monitoring of rainfall has a very limited utility at the regional and global scale because of the high temporal and spatial variability of rainfall. As a step toward overcoming this problem, microwave remote sensing observations can be used to retrieve the temporal and spatial rainfall coverage because of their global availability and frequency of measurement. This paper addresses the question of whether remote sensing rainfall estimates over a catchment can be used for water balance computations in the distributed hydrological model. The TRMM 3B42V6 rainfall product was introduced into the hydrological cycle simulation of the Yangtze River Basin in South China. A tool was developed to interpolate the rain gauge observations at the same temporal and spatial resolution as the TRMM data and then evaluate the precision of TRMM 3B42V6 data from 1998 to 2006. It shows that the TRMM 3B42V6 rainfall product was reliable and had good precision in application to the Yangtze River Basin. The TRMM 3B42V6 data slightly overestimated rainfall during the wet season and underestimated rainfall during the dry season in the Yangtze River Basin. Results suggest that the TRMM 3B42V6 rainfall product can be used as an alternative data source for large-scale distributed hydrological models.

A distributed hydrological model with its application to the Jinghe watershed in the Yellow River Basin

For the purpose of water resources management in the Yellow River Basin with highly spatial difference, a daily distributed hydrological model was proposed, of which the determination of spatially-distributed parameters and model inputs processing were performed by means of GIS/RS. In the model, the computation of runoff yield was based on the topography index method and flow routing was modeled by Maskingum method. The operation of the model is followed by means of “command structure” technique based upon the topography of river network. A case study using the model was conducted for the Jinghe watershed, which locates at the middle Yellow River Basin. The simulation of the hydrological processes in 1996 has shown that water quantity balance errors were less than 5% and the Nash-Sutcliffe coefficient arrived at 0.7, indicating that the model structure is justifiable, and the precision of the model can satisfy the purpose of water resources management.

A New Algorithm to Automatically Extract the Drainage Networks and Catchments Based on Triangulation Irregular Network Digital Elevation Model

A new algorithm to automatically extract drainage networks and catchments based on triangulation irregular networks(TINs) digital elevation model(DEM) was developed. The flow direction in this approach is determined by computing the spatial gradient of triangle and triangle edges. Outflow edge was defined by comparing the contribution area that is separated by the steepest descent of the triangle. Local channels were then tracked to build drainage networks. Both triangle edges and facets were considered to construct flow path. The algorithm has been tested in the site for Hawaiian Island of Kaho'olawe, and the results were compared with those calculated by ARCGIS as well as terrain map. The reported algorithm has been proved to be a reliable approach with high efficiency to generate well-connected and coherent drainage networks.

Simulation of astronomical solar radiation over Yellow River Basin based on DEM

Based on the developed distributed model for calculating astronomical solar radiation (ASR), monthly ASR with a resolution of 1 km×1 km for the rugged terrains of Yellow River Basin was calculated, with DEM data as the general characterization of terrain. This model gives an all-sided consideration on factors that influence the ASR. Results suggest that (1) Annual ASR has a progressive decrease trend from south to north; (2) the magnitude order of seasonal ASR is: summer>spring>autumn>winter; (3) topographical factors have robust effect on the spatial distribution of ASR, particularly in winter when a lower sun elevation angle exists; (4) the ASR of slopes with a sunny exposure is generally 2 or 3 times that of slopes with a shading exposure and the extreme difference of ASR for different terrains is over 10 times in January; (5) the spatial differences of ASR are relatively small in summer when a higher sun elevation angle exists and the extreme difference of ASR for different terrains is only 16% in July; and (6) the sequence of topographical influence strength is: winter>autumn>spring>summer.

Flash flood hazard mapping: A pilot case study in Xiapu River Basin, China

Flash flood hazard mapping is a supporting component of non-structural measures for flash flood prevention. Pilot case studies are necessary to develop more practicable methods for the technical support systems of flash flood hazard mapping. In this study, the headwater catchment of the Xiapu River Basin in central China was selected as a pilot study area for flash flood hazard mapping. A conceptual distributed hydrological model was developed for flood calculation based on the framework of the Xinanjiang model, which is widely used in humid and semi-humid regions in China. The developed model employs the geomorphological unit hydrograph method, which is extremely valuable when simulating the overland flow process in ungauged catchments, as compared with the original Xinanjiang model. The model was tested in the pilot study area, and the results agree with the measured data on the whole. After calibration and validation, the model is shown to be a useful tool for flash flood calculation. A practicable method for flash flood hazard mapping using the calculated peak discharge and digital elevation model data was presented, and three levels of flood hazards were classified. The resulting flash flood hazard maps indicate that the method successfully predicts the spatial distribution of flash flood hazards, and it can meet the current requirements in China.

Morphometric Analysis of Drainage Basins in the Western Arabian Peninsula Using Multivariate Statistics

The uplift of the Arabian Shield and the opening of the Red Sea led to the development of steep drainage systems in the Western Arabian Peninsula. Although the Peninsula has been studied from a geological perspective, in relation to oil production, plate tectonics and eolian systems such as sand dunes, the steep mountainous drainage basins have received much less attention. This paper aims to assess the characteristics and development of 36 drainage basins in the Western Arabian Peninsula, using a digital elevation model (DEM), principal component analysis (PCA), and hierarchical cluster analysis (CA). Three major principal components (PC1 to PC3) are found to explain 73% of total variance. CA divided the basins into two or four groups. The division by CA strongly reflects PC1, showing that the two analyses give comparable results. PC1 strongly reflects basin dimensions and drainage texture, and their positive correlations indicate the significant effect of basin relief and slope on mass wasting and limited stream incision in small basins under an arid climate. PC2 mainly reflects the effect of bedrock geology, suggesting that volcanic rocks tend to produce more elongated and less eroded immature basins than crystalline rocks do. PC3 mainly reflects the basin relief and slope and the length of each stream segment, which may also reflect the effect of mass wasting on stream development.

Morphotectonic and Lithostratigraphic Analysis of Intermontane Karewa Basin of Kashmir Himalayas,India

Morpho-tectonic study plays an important role in deciphering the effects of tectonic activity in the geomorphic evolution of the drainage basins.Romushi watershed forms one of the major watersheds of the intermontane Karewa Basin of Kashmir Valley.The Karewa sediments are characterized by glacio-fluvio-lacustrine deposits capped by the aeolian loess.The geomorphic,morphometric and lithostratigraphic studies of these cap deposits have been carried out to elucidate the effect of tectonics on the geomorphic evolution of Romushi Watershed.Geomorphic mapping was carried out using GPS measurements,DEM at 30m resolution,Topographic Position Index(TPI) model,topographic maps,LANDSAT TM Imagery and field data.Morphometric and morphotectonic analyses in GIS environment were used to calculate various geomorphic indices(Mountain Front Sinuosity Index,Bifurcation Ratio,Asymmetry Factor,River Profile,etc).These indices reveal that the tectonic uplift observed in the region due to Himalayan orogeny coupled with mass movement and aeolian deposition have dominated the landscape evolution of intermontane Karewa Basin of Kashmir throughout the Late Quaternary Period.Additional data from lithostratigraphic measurements were analyzed to understand the geomorphic evolution of intermontane Karewa Basin.The data revealed that the basin has experienced differential uplift and erosion rates from time to time in the geological past.This was corroborated by the results from the morphometric and morphotectonic analysis.

Application of hydrometeorological coupled European flood forecasting operational real time system in Yellow River Basin

This study evaluated the application of the European flood forecasting operational real time system （EFFORTS） to the Yellow River. An automatic data pre-processing program was developed to provide real-time hydrometeorological data. Various GIS layers were collected and developed to meet the demands of the distributed hydrological model in the EFFORTS. The model parameters were calibrated and validated based on more than ten years of historical hydrometeorological data from the study area. The San-Hua Basin （from the Sanmenxia Reservoir to the Huayuankou Hydrological Station）, the most geographically important area of the Yellow River, was chosen as the study area. The analysis indicates that the EFFORTS enhances the work efficiency, extends the flood forecasting lead time, and attains an acceptable level of forecasting accuracy in the San-Hua Basin, with a mean deterministic coefficient at Huayuankou Station, the basin outlet, of 0.90 in calibration and 0.96 in validation. The analysis also shows that the ;simulation accuracy is better for the southern part than for the northern part of the San-Hua Basin. This implies that, along with the characteristics of the basin and the mechanisms of runoff generation of the hydrological model, the hydrometeorological data play an important role in simulation of hydrological behavior.

Digitally Mapping the Hydro-Topographical Context for Community Planning: A Case Study for the Upper Choapa River Watershed in Chile

Urban and non-urban settlements in many regions are usually located on the lands bordering shores, rivers, canals or streams. However, housing complexes, landfills, and areas for agriculture and mining are often assigned to locations without sufficiently detailed hydrographic information about subsequent potential if not actual flow and flooding impacts. Yet, for sustainable community planning with emphasis on harmonizing social, economic, environmental and institutional aspects, such information is essential. This article demonstrates how this need can in part be accommodated by way of digital elevation and wet-area modelling and mapping using the upper component of the Choapa watershed in Chile as a case study. The terrain of this area has sharply incised valleys, with communities, fields and roads strung narrowly along the Choapa River and its tributaries. Above these locations along the Estero de Los Pelambres near the Chile-Argentina border are major mining and mineral refining activities. This article provides modelling and mapping details about the wet-to-moist area zonation along the upper Choapa River valleys, and addresses some of the mining-induced changes from 2000 to 2010.

Quantitative Estimation of Altimetric Variations Using Residual DEM from Topographical Maps between Two Epochs 1893 and 1985: Case Study: The Endorheic Basin of Enfidha-Tunisia

This article endeavours to analyse the recent deformation in the Enfidha region. This analysis has been carried out using the Residual Digital Elevation Model (DEM). It is the altimetric difference between two DEM generated from the contour lines of two topographical maps over a period of 100 years. This deformation has been studied by some authors who report the presence of recent ground movements by comparing contour lines with a downward trend in elevation from 1893 to 1985. In 2006, this study area was marked by the presence of two earthquakes that occurred in several coastal cities located in the northeastern part of Tunisia. Our study involves a quantitative estimation of altimetric variations under a Geographic Information System (GIS) environment. Our proposed methodology aims at the mapping of residual (DEM) and the extraction of parameters that have a morphological and morphostructural signature. The extraction of quantitative morphostructural parameters requires the integration of multi-source and multi-scale data. This can only be done if the problem of heterogeneity at the level of scale and coordinate system is solved through the use of GIS tools and the obtainment of the vectorial shapefile format. Then, in order to compare the DEM generation errors with reference to recent and old data, they must be projected in the same projection system and on the same scale. The available data are two topographic maps of Enfidha which represent two different epochs. The first one is an old topographic map of 1893 (type 1922) at a scale of 1:50,000 and the second one is a recent topographic map of 1985 at a scale of 1:25,000. These topographical maps have the Lambert (IGN) projection system. This methodological approach, based on residual (DEM), allows to highlight an estimated subsidence of 3 m/100years located in the Enfidha plain and extends to the south coast of Cap Bon area in Tunisia. The variation of the contour lines shape between the old and the recent map can be studied in correlation with a relay structure fault observed and recognized by some analysts in this area. These relay accidents remain active according to the results obtained by the residual (DEM) and validated by the field observations of two sites that we have carried out in the Enfidha endorheic basin.

基于区域地质图与数字高程模型的地层埋深预测方法及应用

对于页岩气、水溶气等非常规天然气资源早期选区评价,往往因为缺乏地震资料导致难以依赖地震构造解释获得目的层的埋深,故借助其他非地震资料有效预测目的层区域性埋深具有重要意义。区域地质图与数字高程模型(DEM)都是广泛覆盖且容易获取的基础性资料。利用区域地质图蕴含的地层产状、地下构造起伏趋势、地层埋深和地表出露地层年代的关系等信息,再叠合DEM地表高程,建立了一种有效预测目的层构造高度和埋深的新方法。利用四川盆地及周缘地区36幅1∶20万区域地质图和美国航空航天局(NASA)数字高程模型资料,预测了该区下志留统龙马溪组底界埋深,据此编制的龙马溪组底界埋深等值线图为该区页岩气保存条件评价提供了重要参数。该方法不仅可为页岩气早期选区评价提供有效支撑,还可应用于深部高压含水层中水溶气的资源评价、深部咸含水层CO_(2)地质封存的构造优选。