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Comparative Mountain hydrology: A Case Study of Wis?ok River in Poland and Chaohe River in China

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Chinese Geographical Science 2015年第1期25卷 1-12页

作者： Leszek SOBKOWIAK LIU Changming department of hydrology and Water Management Institute of Physical Geography and Environmental Planning Adam Mickiewicz University Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences

Hydrological processes in river basins of similar size and morphology may differ significantly due to different climatic conditions. This paper presents a comparative analysis of hydrological characteristics of two river basins located in different climatic zones: the Wisok River Basin in the south-eastern Poland and the Chaohe River Basin in the northern China. The criteria of their choice were similarities in the basin area, main river length and topography. The results show that climate plays a key role in shaping fluvial conditions within the two basins. It is concluded that: 1) precipitation in the Wisok River Basin is more evenly distributed in the yearly cycle, while in the Chaohe River Basin it is highly concentrated in the few summer months; 2) spring snowmelt significantly contributes to runoff in the Wisok River Basin, while its role in the Chaohe River Basin is negligible; 3) in the Wisok River Basin, besides the peak flow in spring, there is also a period of high water in summer resulting from precipitation, while in the Chaohe River Basin there is only one high water period in summer; 4) the Wisok River Basin shows relatively higher stability in terms of the magnitude of intra- and inter-seasonal discharges; 5) during the multi-year observation period, a decrease in both precipitation and runoff was recorded in the two river basins.

关键词： comparative hydrology mountain area Wislok River Basin Chaohe River Basin seasonal changes inter-annual changes

Erodibility study of sediment in a fast-flowing river

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International Journal of Sediment Research 2019年第2期34卷 144-154页

作者： Cheng He David Nguyen Watershed hydrology and Ecology Research Division National Water Research InstituteEnvironment and Climate Change Canada department of Environmental Engineering University of Guelph

Determination of sediment stability in the field is challenging because bed shear stress(BSS),a determining factor of sediment erosion,can’t easily be directly *** tackle this challenge and reliably assess sediment erodibility in a fast flowing river,a standalone underwater camera system and a new insitu flume(ISF)were developed and applied in this *** camera system was used to record sediment movement and the new ISF was used for measuring critical bottom shear stress(CBSS).The camera can be deployed alone in water to record videos or take pictures with light emitting diode(LED)lighting and flexible schedule *** ISF is based on the concept that the amount of force needed to erode the same particle under different flow conditions should be *** high resolution Acoustic Doppler Current Profilers(ADCP)also were deployed in the field to collect velocity-depth profiles which are used by conventional methods to calculate BSS with the law of the *** sediment erodibility was then assessed based on the comparison between the obtained CBSS and BSS and then further verified with the recorded observations from the deployed *** results reveal that the widely used conventional method can produce large uncertainties and is not adequate to provide meaningful conclusion under these conditions.

关键词： Sediment erodibility Bed shear stress Critical bed shear stress Underwater camera

Application of fuzzy logic approach for landslide susceptibility mapping in Garuwa sub-basin, East Nepal

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Frontiers of Earth Science 2012年第4期6卷 420-432页

作者： Prabin KAYASTHA department of hydrology and Hydraulic Engineering Vrije Universiteit Brussel Brussels 1050 Pleinlaan 2 Belgium Mountain Risk Engineering-Unit Tribhuvan University Kirtipur Kathmandu Nepal

Landslide is one of the major natural disasters which cause extensive loss of life and property. During the last three decades, different researchers have developed different methodologies to prepare landslide susceptibility mapping and hazard assessment in the world. The main goal of this paper is to apply a fuzzy logic approach to landslide susceptibility mapping in the Garuwa sub-basin area, East Nepal. Eight different causative factors are considered： slope angle, slope aspect, slope shape, relative relief, distance from drainage, land use, geology, and distance from active faults. Likelihood ratios are obtained for each class of causative factors by comparison with past landslide occurrences. Then, the likelihood ratios are normalized between zero and one to obtain fuzzy membership values. Next, different fuzzy operators are applied to generate landslide susceptibility maps. Compar- ison with the landslide inventory map reveals that the fuzzy gamma （γ） operator with a y-value of 0.70 yields the best prediction accuracy which is then used to produce the final landslide susceptibility zonation map.

关键词： landslide susceptibility fuzzy logic GIS Garuwa sub-basin Nepal

Tidal Flushing Time of Marine Fish Culture Zones in Hong Kong

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China Ocean Engineering 2011年第4期25卷 625-643页

作者：毛劲乔黄子文李行伟蔡景华 State Key Laboratory of hydrology-Water Resources and Hydraulic Engineering Hohai University department of Civil Engineering The University of Hong Kong Hong Kong University of Science and Technology

Accurate determination of flushing time is crucial for maintaining sustainable production in fish culture zones （FCZs）, as it represents the physical self-purification capability via tidal exchange with clean water in the outer sea. However, owing to the temporal and spatial complexity of the coastal flushing process, existing methods for determining flushing time may not be generally applicable. In this paper, a systematic method for determining the flushing time in FCZs is presented, in which bathymetry, runoff, tidal range and stratification are properly accounted for. We determine the flushing time via numerical tracer experiments, using robust 3D hydrodynamic and mass transport models. For FCZs located in sheltered and land-locked tidal inlets, the system boundary can be naturally defined at the connection with the open sea. For FCZs located in open＇waters, hydrodynamic tracking is first used to assess the extent of tidal excursion and thus delimit the initial boundary between clean water and polluted water. This general method is applied to all designated marine FCZs in Hong Kong for both the dry and wet seasons, including 20 sheltered FCZs （in semi-enclosed waters of Tolo Harbour, Mirs Bay, and Port Shelter） and 6 FCZs in open waters. Our results show that flushing time is the longest in inner Port Shelter （about 40 days in dry season）, and the shortest for the FCZs in open waters （less than one week in dry season）. In addition, the flushing time in dry season is commonly longer than that in wet season： 20%~40% for most well-sheltered FCZs; 2.6-4 times for the others. Our results indicate a positive correlation between the flushing time and distance to open boundary, supporting the view that the flushing time of a FCZ is closely related to its location. This study provides a solid basis for mariculture management such as the determination of carrying capacity of FCZs.

关键词： flushing time fish culture zone hydrodynamic tracking carrying capacity tidal exchange physical

PARAMETER IDENTIFICATION FOR MODELING RIVER NETWORK USING A GENETIC ALGORITHM

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Journal of Hydrodynamics 2010年第2期22卷 246-253页

作者： TANG Hong-wu XIN Xiao-kang DAI Wen-hong XIAO Yang State Key Laboratory of hydrology-Water Resources and Hydraulic Engineering Hohai University Nanjing210098 China

The simulation of a one-dimensional river network needs to solve the Saint-Venant equations,in which the variable parameters normally have a significant influence on the model accuracy.A Trial-and-Error approach is a most commonly adopted method of parameter calibration,however,this method is time-consuming and requires experience to select the appropriate values of ***,simulated results obtained via this method usually differ between *** article combines a hydrodynamic model with an intelligent model originated from the Genetic Algorithm（GA） technique,in order to provide an intelligent simulation method that can optimize the parameters *** with current approaches,the method presented in this article is simpler,its dependence on field data is lower,and the model accuracy is *** the optimized parameters are taken into the hydrodynamic numerical model,a good agreement is attained between the simulated results and the field data.

关键词： river network simulation genetic algorithm parameter identification

Assessment of runoff changes in the sub-basin of the upper reaches of the Yangtze River basin, China based on multiple methods

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Journal of Arid Land 2024年第4期16卷 461-482页

作者： WANG Xingbo ZHANG Shuanghu TIAN Yiman department of Water Resources China Institute of Water Resources and Hydropower ResearchBeijing 100038China College of hydrology and Water Resources Hohai UniversityNanjing 210098China

Quantitative assessment of the impact of climate variability and human activities on runoff plays a pivotal role in water resource management and maintaining ecosystem *** study considered six sub-basins in the upper reaches of the Yangtze River basin,China,to reveal the trend of the runoff evolution and clarify the driving factors of the changes during 1956–*** regression,Mann-Kendall test,and sliding t-test were used to study the trend of the hydrometeorological elements,while cumulative distance level and ordered clustering methods were applied to identify mutation *** contributions of climate change and human disturbance to runoff changes were quantitatively assessed using three methods,i.e.,the rainfall-runoff relationship method,slope variation method,and variable infiltration capacity(Budyko)hypothesis ***,the availability and stability of the three methods were *** results showed that the runoff in the upper reaches of the Yangtze River basin exhibited a decreasing trend from 1956 to 2020,with an abrupt change in *** attribution analysis,the runoff series could be divided into two phases,i.e.,1961–1985(baseline period)and 1986–2020(changing period);and it was found that the rainfall-runoff relationship method with precipitation as the representative of climate factors had limited usability compared with the other two methods,while the slope variation and Budyko hypothesis methods had highly consistent *** factors showed different effects in the sub-basins of the upper reaches of the Yangtze River ***,human disturbance was the main factor that contributed to the runoff changes,accounting for 53.0%–82.0%;and the contribution of climate factors to the runoff change was 17.0%–47.0%,making it the secondary factor,in which precipitation was the most representative climate *** results provide insights into how climate and anthropogenic changes synergistically influence the runoff of t

关键词： economic belt runoff change influencing assessment climate human activities

Laboratory-scale investigation of the material distribution characteristics of landslide dams in U-shaped valleys

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Journal of Mountain Science 2023年第3期20卷 688-704页

作者： JIAN Fu-xian CAI Zheng-yin GUO Wan-li Geotechnical Engineering department Nanjing Hydraulic Research InstituteNanjing 210024China State Key Laboratory of hydrology-Water Resources and Hydraulic Engineering Nanjing 210024China

Material distribution characteristics during sliding and depositing is particularly significative to investigate the internal structure and spatial variation of landslide dams,which are fundamentally determining the mechanical and hydraulic behavior and the susceptibility to cause dam ***,limited by longevity shortages and special geographic environments,the material distribution characteristics and their formation mechanisms are difficult to observe in the ***,an experimental apparatus modeling a landslide dam was developed in this paper,designing three sampling methods with two valley *** internal deposit characteristics,void ratio variation and relative content of the particle size range(PSR)were analyzed,and the mechanics of deposit structure were also delicately *** results indicate that granular material deposited in valley shows a structure of inverse grain size accumulation in both vertical and horizontal directions,exhibiting spatial variability of particle gradation and void *** characteristic PSR decreases from 22-30 mm in the two-dimensional state to 10-14 mm in the threedimensional *** excitation and vibration sieve are the intrinsic mechanisms of granular flow segregation,intrinsically inducing the formation of inverse grading deposit ***,spatial variability in size is mainly trig gered by segregation,whereas coarse particle content and deposition boundaries merely exacerbate the difference degree.

关键词： Landslide dam IInverse grading structure Granular flow segregation Material spatial variability Deposit characteristics

FAST MULTIPOLE SINGULAR BOUNDARY METHOD FOR LARGE-SCALE PLANE ELASTICITY PROBLEMS

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Acta Mechanica Solida Sinica 2015年第6期28卷 626-638页

作者： Wenzhen Qu Wen Chen State Key Laboratory of hydrology-Water Resources and Hydraulic Engineering Center for Numerical Simulation Software in Engineering and SciencesCollege of Mechanics and MaterialsHohai University department of Mathematics University of North Carolina

The singular boundary method （SBM） is a recent meshless boundary collocation method that remedies the perplexing drawback of fictitious boundary in the method of fundamental solutions （MFS）. The basic idea is to use the origin intensity factor to eliminate singularity of the fundamental solution at source. The method has so far been applied successfully to the potential and elasticity problems. However, the SBM solution for large-scale problems has been hindered by the operation count of O（N^3） with direct solvers or O（N^2） with iterative solvers, as well as the memory requirement of O（N^2）. In this study, the first attempt was made to combine the fast multipole method （FMM） and the SBM to significantly reduce CPU time and memory requirement by one degree of magnitude, namely, O（N）. Based on the complex variable represen- tation of fundamental solutions, the FMM-SBM formulations for both displacement and traction were presented. Numerical examples with up to hundreds of thousands of unknowns have successfully been tested on a desktop computer. These results clearly illustrated that the proposed FMM-SBM was very efficient and promising in solving large-scale plane elasticity problems.

关键词： fast multipole method singular boundary method meshless boundary collocation method elasticity problems

Artificial neural network simulation for prediction of suspended sediment concentration in the River Ramganga,Ganges Basin,India

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International Journal of Sediment Research 2019年第2期34卷 95-107页

作者： Mohd Yawar Ali Khan Fuqiang Tian Faisal Hasan Govind Joseph Chakrapani Institute of hydrology and Water Resources Department of Hydraulic EngineeringSchool of Civil EngineeringTsinghua University department of Earth Sciences Indian Institute of Technology Roorkee department of Mechanical Engineering Aligarh Muslim University

The relation between the water discharge(Q) and suspended sediment concentration(SSC)of the River Ramganga at Bareilly,Uttar Pradesh,in the Himalayas,has been modeled using Artificial Neural Networks(ANNs).The current study validates the practical capability and usefulness of this tool for simulating complex nonlinear,real world,river system processes in the Himalayan *** modeling approach is based on the time series data collected from January to December(2008-2010)for Q and *** ANNs(T1-T3)with different network configurations have been developed and trained using the Levenberg Marquardt Back Propagation Algorithm in the Matlab *** were optimized using the enumeration technique,and,finally,the best network is used to predict the SSC values for the year *** values thus obtained through the ANN model are compared with the observed values of *** coefficient of determination(R2),for the optimal network was found to be *** study not only provides insight into ANN modeling in the Himalayan river scenario,but it also focuses on the importance of understanding a river basin and the factors that affect the SSC,before attempting to model *** the temporal variations in the study area,it is possible to model and successfully predict the SSC values with very simplistic ANN models.

关键词： ANN Water discharge Suspended sediment concentration prediction Ramganga River Himalayas