| [Chinese] |
Impact of Flood Events from Different Source Areas on
Chann el Transects
Adjustment at the Wandering braided Reach of the Lower Yel low River
ZHANG Ou-yang1,2, XU Jiong?xin2?ZHANG Hong-wu1
(1.Department of Hydraulic Engineering, Tsinghua University, China;
2.Institute of Geographic Sciences and Natural Resources Research, CAS,)
Abstract:
¡¡¡¡Flood events from the upper clear water producing area and the lower clear wat er producing area both have abundant runoff and low sediment concentration, but they have different impacts on channel deformation. Flood events from the upper clear water producing area generally have the sediment concentration just slight ly larger than the carrying capacity, which makes the sediment slightly deposite d in the main channel and thus cause the width to depth ratio slightly increase. Flood events from the lower clear water producing area generally have very smal l sediment concentration that the water have excessive energy to carry sediment, thus the main channel will be scoured that causes the width to depth ratio larg ely decreased.
¡¡¡¡Flood events from the coarser sediment producing area and the fine sediment prod ucing area both have large peak discharge and high sediment concentration, but t hey also have different impacts on channel deformation. Many of the flood events from the coarser sediment producing area are the hyper-concentration flow that makes the sediment deposit heavily on the flood plain and scour in the main chan nel and thus cause the width to depth ratio decrease. Flood events from the fine sediment producing area may make the sediment deposited both in main channel an don flood plain and thus the width to depth ratio of the channel will not chang ed obviously.
Key
words: channel transverse adjustment; flood events from dif ferent source areas;
the Yellow River
Fluvial Process Pattern
of the Heavy Sediment-carrying Rivers and Design of Water
Diversion Structure in Xinjiang Plain Area
LI Shan, WEI Shu-fan, YAN Xiao-da
(The Planning & Design Administration of Xinjiang Department of Water Resources,
Urumqi)
Abstract: More than 400 water diversion structures built in Xinj iang are located mostly in the mountain pass of the rivers, and partially in the fine-silt riverbed in the plain areas.Owing to the gentle slope of the fine-silt riverbed,the low ability of erosion resistance, and the complicated boundary conditions of the river flow,building water diversion works across rivers has great influence s on the characteristics of erosion and sedimentation in the original river,and the river flow is comparatively sensitive to the change of boundary conditions.So, it is very important to make deep study on the water diversion structures in the sediment-carrying rivers in the plain areas.By analyzing the fluvial process pattern of the rivers in the plain areas,this article proposes some main points and methods of the design for water diversion structures in the plain areas,with some discussions on the problems concerned.
Key words:
Xinjiang; plain area; sediment-carrying rivers and w ater diversion
structure
Fractal Characteristics
of Discharge and Sediment Discharge in the PearlRiver Delta
YANG Qing-shu1?2, FU Jia-mo1, LUO
Zhang-ren2, YANG Gan-ran2
(1.State Key Laboratory of Organic Geochemistry,Guangzhou Institute of Geochemis
try,Chinese Academy of Science,Guangzhou;
Abstract: Based on the discharge and sediment concentration of Gaoyao station at Xijiang main stream,Shijiao station at Beijiang main stream,Mak ou station and Sanshui station of the Pearl River Delta,the Hurst Dimension and fractal dimension of discharge and sediment discharge were calculated by rescale d range analysis(R/S).The study shows that fractal dimensions of discharge are greater than those of sediment discharge;the fractal dimensions of discharge an d sediment concentration at Sanshui Station are greater than those at Shijiao station.The results also indicate that the discharge and sediment at Sanshui sta tion are different from those at Shijiao station.
Key words:
fractal; rescaled range analysis; the flow and sedim ent;Xijiang and Beijiang Delta
Study on River Patterns of the Tarim River
WANG Yan-gui, HU Chun-hong, ZHOU Wen-hao, LI Xi-xia, ZHU Bi-sheng
(China Institute of Water Resources and Hydropower Research)
Abstract: Based on the hydrologic data and river regimes by aerial survey,the river patterns and their causes of formation in the trunk channel of the Tarim river were studied in this paper. The study shows that Tarim river can be divided into three river patterns: the wandering stream,meandering stream and transitional reach,of which the wandering stream,meandering stream and transitional reach are respectively located in the upper reach of Xinqiman (from Alaer hydrographic station to the Deer farm in Shaya county,Xinqiman is also a hydrographic station),the Xinqiman reach (from Deer farm to Qumaogejin) and the lower reach of Xinqiman (from Qumaogejin to Qiala hydrographic station).The lower reach downstream Qiala hydrographic station could be called as a developing meandering stream because of water shortage.River boundary and the oncoming flow and sediment,such as the dense and sparse vegetation by shrub and diversiform-leaved poplar?flooding?and diversion in the both sides of the Tarim river,are very important factors in the formation of the river patterns.
Key words: trunk channel of the Tarim river; river pattern; cause of formation in the river pattern
Development,Practice and
Understanding of Sediment Treatment of the Yellow River
WANG Kai-rong, LI Wen-xue, ZHENG Chun-mei
(Yellow River Institute of Hydraulic Research)
Abstract:
Based on the general analysis of characteristics and variation tendencies of wat
er and sediment of the Yellow River,this paper reviews the background o f various sediment
treatment measures,the practice results and the problems exis ted.Treating sediment of the
Yellow River is a long term,complex and extremely h ard work.The comprehensive sediment
treatment system of ¡¡ãretaining,discharging, regulating,desilting, and dredging¡¡À could
be brought into full play only if the plan is unified with overall considering that
comprehensive water and soil cons ervation works are performed on a big scale,water and
sediment control and regul ating systems are established,and water and sediment are
utilized and treated re asonably.
Key words: sediment of the Yellow River; treatment; practice; understanding
Experimental
Study on Evolvement of the Yellow River Mouth in Action of the Imported Seawater
CAO Wen-hong, HU Chun-hong, JIANG Nai-sen
(China Institute of Water Resources and Hydropower Reseach)
Abstract:
Based on physical model, the article studies and discusses processes of the retr
ogressive and streamwise erosion, the corresponding equilibrium slope, scouri ng effects,
and water level changes in the upper or down river of the imported s eawater point. The
experimental results demonstrate that the imported seawater c ombining with the operation
of Xiaolangdi reservoir can extend the life-span of the
use of river mouth channels, alleviate the flood pressure in the Shandong r each of the
lower Yellow River, and prolong the rise of riverbed.
Key words: the Yellow River mouth; seawater; retrogressive erosion; streamwise erosion
Numerical Simulation of
Supercritical Flow and Sediment in Channel with Continuous Curves
WANG Shuang-ming1,3, YANG Hong2,
PAN Guang-zai3
(1.Dept. of Mechanics of Shanghai Jiaotong University,2.River and Harbor Engineering
Department,Nanjing Hydraulic Research Institute,3.Dept. of Hydraulic Engineering,Taiyuan
University of Technology)
Abstract:
A two-dimensional flow and sediment model is proposed for channel with continuo
us curves, and is solved by the finite difference method. It can be used to calcul ate the
flow and sediment scouring and deposition in the Taohe River in Yangquan city,
Shanxi Province, China. The results show the model is applicable for the des ign of
hydraulic engineering.
Key
words: continuous curve; supercritical flow; sediment; numerical simulation
River
Shrinkage and Harnessing Countermeasures of the Lower Weihe River in Recent Period
CHEN Jian guo, HU Chun hong, DAI
Qing
(China Institute of Water Resources and Hydropower Research)
Abstract: In recent years, an obvious river shrinkage in the lower Weihe River has been ob served due to the constant high elevation at Tongguan and the reduction of oncom ing flow and sediment. Such situation causes high water levels, serious flood d isasters occurred often during low flow discharges, and a series n ew problems, such as increasing of deposition rate, narrowing of main channel, decreasing of flow-carrying capacity, higher water level at the same flow discha rge, prolonging of flood movement, more river bends, unstable main channel, seri ous siltation at the mouth of branches, and much more difficult flood prevention.
¡¡¡¡Based on
above analyses, this paper pointed out the harnessing countermeasures of the Lower Weihe
River: lowering Tongguan elevation, river training in the Lowe r Weihe River, routing of
Beiluohe River, harnessing in confluence region of the Yellow, Weihe and Beiluohe
Rivers, operation of flood and sediment regulation in Dongzhuang reservoir, and water
transfer from other river basin to the Weihe River.
Key words: the Lower Weihe River?recent period?river shrinkage?harnessing countermeas ures
Key
Issues in Heavy metal Sorption by Sediments
SUN Wei-ling?NI Jin-ren
?The Key Laboratory of Water and Sediment Sciences, Ministry of Education,
Depa rtment of Envinmental Engineering, Peking University)
Abstract:
Based on asystematic review of the recent studies on heavy metal sorption by sediments,this paper investigates the
classifications?primary issues?impact factors and mechanisms of sorption
processes Both sorption
and speciation are
discussed. Various methods have been compared. Deficiencies in the present stu dies are
also indicated As
results?perspectives are made on the significance o f the study on heavy?metal sorption by sediments in hyper concentrated
solid- liquid systems?which is of potential practical use in
environmental and ecologi cal protection in large rivers like the Yellow River.
Key
words: sediment?heavy metal?sorption speciation
Finite
Element Method for 2-D Flow and Sediment Mathematical M odel in Channels
(Yangtze River Scientific Research Institute, YRSRI)
Abstract: A 2-D flow and sediment mathematical model by the fin ite element method is established in the article. Based on the former research, methods of Mass Concentration and Compressed Memory are used to reduce the needed memory . Since the methods of Prediction-Correct-Iteration and Unsteady-Steady-Unst eady are adopted, the timestep becomes longer and the calculation is greatly r educed. Simulation is carried out in the Jianli reach of the lower Jingjiang river and shows that the calculated results are in good agreement with the fiel d data.
Key words:
2-D Mathematical
Model for Nonuniform Sediment Transport in Ya ngtze Estuary
CAO Zhen-yi, HU Ke-lin
(State Key Laboratory of Estuarine and Coastal, East China Norma l University, Shanghai)
Abstract:
A 2-D horizontal mathematical model is established fo rsuspended sediment
transport based on the character of hydraulic and suspended sediment in
Yangtze estuary. In the model the effects of wave on momentum equation and se diment
capacity are considered. The fine sediment settling velocity due to flocc ulation is
determined by sediment grain, salt, sediment concentration, and flow turb ulence. A
boundary?fitted curvilinear coordinate system has been deployed
to ob tain a more accurate solution of SSC. The operato-splitting algorithm and the
Ultimate Quickest scheme have been used to solve the sediment transport equation . The
calculated results are in close agreement with field observation, which sh ows this model
can predict suspended sediment transport in Yangtze estuary.
Key words:
sediment-carrying capacity; suspended sediment numerical
model; Yangtze Estuary
Model Study on
Sedimentation and Control Measures in Baihepu Reservoir
HUANG Bing-bin, WANG Li-xu, ZHANG
Chun-yi, LIU Xiang-zhong
(Beijing Hydraulic Research Institute)
Abstract:
Constructed in 1973, the Baihepu Reservoir Project has played an important
role in flood control, irrigation, hydropower generation? and interbasin div ersion.
The sedimentation has been influencing the water diversion from the rese rvoir since 1997.
Based on analysis of the oncoming runoff and suspended load, a nd the sediment
distribution of the reservoir, a physical model study is carried out to explore the
development and control measures of sedimentation. Three ope rational schemes are
simulated and the results of the study show that the one wi th sediment guiding dike is
much more effective in preventing the water diversio n tunnel inlet sedimentation,
compared with the other two alternatives, which ar e the existing operational mode and
high water level operational mode. The sedim ent guiding dike scheme can keep the water
diversion project running for more th an twenty years or even longer if other reasonable
schemes are applied simultane ously.
Key words: reservoir sedimentation; physical model; control mea sures; sediment guiding dike