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River channel flood forecasting method of coupling wavelet neural network with autoregressive model 被引量:1
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作者 李致家 周轶 马振坤 《Journal of Southeast University(English Edition)》 EI CAS 2008年第1期90-94,共5页
Based on analyzing the limitations of the commonly used back-propagation neural network (BPNN), a wavelet neural network (WNN) is adopted as the nonlinear river channel flood forecasting method replacing the BPNN.... Based on analyzing the limitations of the commonly used back-propagation neural network (BPNN), a wavelet neural network (WNN) is adopted as the nonlinear river channel flood forecasting method replacing the BPNN. The WNN has the characteristics of fast convergence and improved capability of nonlinear approximation. For the purpose of adapting the timevarying characteristics of flood routing, the WNN is coupled with an AR real-time correction model. The AR model is utilized to calculate the forecast error. The coefficients of the AR real-time correction model are dynamically updated by an adaptive fading factor recursive least square(RLS) method. The application of the flood forecasting method in the cross section of Xijiang River at Gaoyao shows its effectiveness. 展开更多
关键词 river channel flood forecasting wavel'et neural network autoregressive model recursive least square( RLS) adaptive fading factor
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Channel changes of the Makou-Tianjiazhen reach in the middle Yangtze River during the past 40 years 被引量:3
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作者 ZHANG Qiang CHEN Yongqin David +1 位作者 JIANG Tong LI Maotian 《Journal of Geographical Sciences》 SCIE CSCD 2007年第4期442-452,共11页
Quantitative analysis was performed on the filling-scouring process for the river reach within Makou and Tianjiazhen, the middle Yangtze River with the help of GIS and DEM techniques. The research results indicate tha... Quantitative analysis was performed on the filling-scouring process for the river reach within Makou and Tianjiazhen, the middle Yangtze River with the help of GIS and DEM techniques. The research results indicate that the river reach between Makou and Tianjiaz- hen was dominated by the scouring process, and the magnitude of scouring is increasing over time. The intensity of scouring process is more in the deep and narrower river reach than shallower and wider ones. The river reach in the Makou and Tianjiazhen river knot is in frequent scouring and filling process, however the river reach upper to the Makou and lower to the Tianjiazhen river knot is in moderate scouring and filling process. The river reach just upstream or downstream to the river knot (e.g. Makou and Tianjiazhen river knot in this research) is dominated by filling process and the river reach in the river knot is dominated by the scouring process. Research results indicate no changes in the boundary of the river but the scouring and the filling magnitude in specific river channel is strong. The filling and the scouring process of the study river reach is greatly impacted by the sediments and water from the upstream of the study river reach. The construction of the Three Gorges Dam just up- stream to Yichang will cause further decrease of the release of the sediment load to the middle and the lower Yangtze River basin, which will further intensify the scouring process of the river channel in the study river reach. 展开更多
关键词 Makou-Tianjiazhen river reach GIS DEM river channel changes
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The analysis on reservoir sediment deposition and downstream river channel scouring after impoundment and operation of TGP 被引量:1
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作者 Lu Jinyou Huang Yue Wang Jun 《Engineering Sciences》 EI 2011年第3期113-120,共8页
According to the measured data after impoundment and operation of the Three Gorges Reservoir,the reservoir sediment deposition and downstream river channel scouring are described briefly and compared with the research... According to the measured data after impoundment and operation of the Three Gorges Reservoir,the reservoir sediment deposition and downstream river channel scouring are described briefly and compared with the research results achieved in the demonstration stage.It is indicated through analysis that the reservoir sediment deposition and downstream river channel scouring during 8-year impoundment and operation are still within the original forecast,so the original forecasting results are feasible.The further observation and comparison should be conducted because the comparison between the observed data and the original forecast is not so sufficient in time and the prototype observation and related research work should be strengthened in the future. 展开更多
关键词 Three Gorges Project (TGP) trial impoundment reservoir sediment deposition downstream river channel scouring
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Geomorphology Processes of Channel Planform Migration on Meandering Rivers 被引量:3
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作者 LIN Zhipeng SHAN Jingfu CHEN Le 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2017年第S1期134-135,共2页
1 Introduction Morphological analysis on the planform migration structure of meandering river is an important basis for the reconstruction of evolution of paleochannel.Besides,it is a significant method for restoratio... 1 Introduction Morphological analysis on the planform migration structure of meandering river is an important basis for the reconstruction of evolution of paleochannel.Besides,it is a significant method for restoration of rivers through the 展开更多
关键词 Geomorphology Processes of Channel Planform Migration on Meandering rivers
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Causes and typical control model of wind-drift sandy lands in abandoned channel of the Yellow River 被引量:1
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作者 Zhang Guo-zhen Yang Li +1 位作者 Xu Wei Sun Bao-ping 《Forestry Studies in China》 CAS 2006年第1期59-64,共6页
The historical formation and development of the abandoned channel of the Yellow River is reviewed and its causes of formation and present condition of prevention and control are analyzed in this paper. Based on this a... The historical formation and development of the abandoned channel of the Yellow River is reviewed and its causes of formation and present condition of prevention and control are analyzed in this paper. Based on this analysis, some ideas about control, critical problems and countermeasures in the next period are proposed with two typical control models as examples. We suggest that in preventing and controlling the wind-drift sandy lands in the region, the emphasis should be to develop, with a greatly expanded effort, a recycling economy. This should realize a combination of two ideas, i.e. integrate combating desertification with a structural adjustment of agricultural and an increase in the income of farmers. 展开更多
关键词 wind-drift sandy land cause of formation control model the abandoned channel of the Yellow river
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A New Method of Assessing Environmental Flows in Channelized Urban Rivers 被引量:2
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作者 Xin-An Yin Zhifeng Yang +3 位作者 Enze Zhang Zhihao Xu Yanpeng Cai Wei Yang 《Engineering》 2018年第5期590-596,共7页
Assessing environmental flows (e-flows) for urban rivers is important for water resources planning and river protection, Many e-flow assessment methods have been established based on species' habitat pro- vision re... Assessing environmental flows (e-flows) for urban rivers is important for water resources planning and river protection, Many e-flow assessment methods have been established based on species' habitat pro- vision requirements and pollutant dilution requirements, To avoid flood risk, however, many urban rivers have been transformed into straight, trapezoidal-profiled concrete channels, leading to the disappearance of valuable species, With the construction of water pollution-control projects, pollutant inputs into rivers have been effectively controlled in some urban rivers, For these rivers, the e-flows determined by tradi- tional methods will be very small, and will consequently lead to a low priority being given to river pro- tection in future water resources allocation and management, To more effectively assess the e-flows of channelized urban rivers, we propose three e-flow degrees, according to longitudinal hydrological con- nectivity (high, medium, and low), in addition to the pollutant dilution water requirement determined by the mass-balance equation, In the high connectivity scenario, the intent is for the e-flows to maintain flow velocity, which can ensure the self-purification of rivers and reduce algal blooms; in the medium connectivity scenario, the intent is for the e-flows to permanently maintain the longitudinal hydrological connectivity of rivers that are isolated into several ponds by means of weirs, in order to ensure the exchange of material, energy, and information in rivers; and in the low connectivity scenario, the intent is for the e-flows to intermittently connect isolated ponds every few days (which is designed to further reduce e-flows), The proposed methods have been used in Shiwuli River, China, to demonstrate their effectiveness, The new methods can offer more precise and realistic e-flow results and can effectively direct the construction and management of e-flow supply projects, 展开更多
关键词 Environmental flow Urban river Channelized rivers river restoration
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Response of the distributary channel of the Huanghe River estuary to water and sediment discharge regulation in 2007
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作者 马妍妍 李广雪 +6 位作者 叶思源 张志恒 赵广明 李景阳 周春艳 丁文洁 杨欣 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2010年第6期1362-1370,共9页
The water and sediment discharge regulation (WSDR) project, which has been performed since 2002 before flood season every year, is of great significance to the river management in China. Until 2007, six experiments ... The water and sediment discharge regulation (WSDR) project, which has been performed since 2002 before flood season every year, is of great significance to the river management in China. Until 2007, six experiments have been fulfilled to evaluate the effect of the project on the natural environment. To fill the gap of investigations, a study on flood and suspended sediment transportation and channel changing along the distributary channel of the Huanghe (Yellow) River was conducted during the WSDR project period in 2007. The lower channel was scoured rapidly and the channel became unobstructed gradually several days after the flood peak water was discharged from the Xiaolangdi Reservoir. Within four days after the flood peak at 3 000 m3/s entered the distributary, the channel in the river mouth area was eroded quickly. Both the mean values of area and depth of the main channel were tripled, and the maximum flood carrying capacity increased to 5 500 m3/s or more. Then, the river channel was silted anew in a very short time after completion of the WSDR. Favored by the WSDR project, the fiver status in April 2008 became better than that of the year before. The adjustment ranges of main channel parameters were about 30%, 10%, and 10% at sections C2, Q4, and Q7, respectively. The process of rapid erosion-deposition was more active 15 km away in the channel from the fiver mouth due to the marine influence. It is reasonable for discharging sediment at concentration peak from Xiaolangdi Reservoir at the end of the flood peak. As a result, the sediment peak reached the river mouth about two days later than that of the water current. In addition, the WSDR project has improved the development of the estuarine wetland. Wetland vegetation planted along the river banks restrained the water flow as a strainer and improved the main channel stability. It is suggested to draw water at mean rate of 150 m3/s from the Huanghe River during flood periods, because at the rate the water in the wetland would be stored and replenished in balance. Moreover, we believe that cropland on the river shoal of the lower Huanghe River should be replaced by wetland. These activities should achieve the Huanghe River management strategy of "To concentrate flow to scour sediment, stabilize the main channel, and regulate water and sediment". 展开更多
关键词 Huanghe (Yellow) river estuary water and sediment regulation river channel adjustment wetland.
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Some thermodynamic criteria for river channel changes
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作者 WANG Zheng Institute of Policy & Management, Chinese Academy of Sciences, Beijing 100080, CHINA 《Journal of Geographical Sciences》 SCIE CSCD 1998年第4期21-29,共9页
A theoretical model of river channel changes is presented, which shows some nonequilibrium thermodynamic criteria of a river channel to bedding and equilibrium.
关键词 river channel changes one-dimensional ideal river geographical system.
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Downstream effects of reservoirs in areas suffering from water deficiency-the case of Hutuo River, China
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作者 SHI Chang-xing (Institute of Geography,Chinese Academy of Sciences, Beijing 100101, China) 《Journal of Geographical Sciences》 SCIE CSCD 2000年第1期37-44,共8页
The Hutuo River is located in the semi-arid areas in China. Due to fat of water resources in these areas, changes in flow regime, mainly reduction in runoff downstream from the reservoirs, have been tremendous. As a r... The Hutuo River is located in the semi-arid areas in China. Due to fat of water resources in these areas, changes in flow regime, mainly reduction in runoff downstream from the reservoirs, have been tremendous. As a result of decrease in flow power and sediment load, the post-dam river showed a less change in channel morphology and the change varied reach by reach. Comparatively, the channel shrinkage may contribute to the flood disasters in the lower reaches of the river in recent years. An obvious increase of channel's hydraulic roughness, the main cause for reduction of flood transmission capacity of the channel, is attributed to vegetation encroachment in the channel. The effects of reservoir construction on ground water level and other environmental aspects are also discussed in the paper. 展开更多
关键词 Hutuo river pest-dam channel adjustment channel's roughness environmental effect
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Impact Analysis of Coastal Engineering Projects on Mangrove Wetland Area Change with Remote Sensing 被引量:4
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作者 李天宏 韩鹏 赵志杰 《China Ocean Engineering》 SCIE EI 2008年第2期347-358,共12页
In the past decades, two large scale coastal engineering projects have been carried out in the Deep Bay surrounded by Shenzhen City and Hong Kong Special Administrative Region. One project is Shenzhen River channel re... In the past decades, two large scale coastal engineering projects have been carried out in the Deep Bay surrounded by Shenzhen City and Hong Kong Special Administrative Region. One project is Shenzhen River channel regulation and the other is the sea reclamation along the seashore on the Shenzhen side. The two projects are very close to the two national nature reserves, specifically Futian in Shenzhen and Mai Po in Hong Kong, which are important wetland ecosystems worldwide. This paper aims to identify and monitor the mangrove wetland changes with time series of Landsat Thematic Mapper images pre and post to the two engineering projects being launched. Coupled analysis of the image interpretation results and tidal data acquired at the same time in the context of the two works reveals that the mangrove wetland area has increased from year 1989 to 1994, and has changed little from year 1994 to 2002. Binary coding is applied to reveal the distribution image of mangrove at each phase, and the coding image shows that the construction of the two coastal engineering projects has caused frequent changes in mangrove spatial distribution. The study also shows that the change is not significant regarding to the precision of the method and the natural evolution of mangrove wetland, and the projects do not cause apparently influences upon the two national mangrove conservation zones at least for the research time period. 展开更多
关键词 mangrove wetland remote sensing sea reclamation river channel regulation the Deep Bay
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Silting in the Lower Courses of Tidal Sluices in China 被引量:2
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作者 张金善 黄建维 杨红 《海洋工程:英文版》 SCIE EI 2004年第1期137-148,共12页
Serious sediment deposition often occurs after the construction of tidal sluices in small or medium-sized tidal muddy estuaries, so desilting or dredging is needed to meet the demands of flood discharge, saltwater ret... Serious sediment deposition often occurs after the construction of tidal sluices in small or medium-sized tidal muddy estuaries, so desilting or dredging is needed to meet the demands of flood discharge, saltwater retaining, and navigation in those areas. In this paper, the problem of sediment deposition induced by construction of tidal sluices is analyzed. Different problems of silting near tidal sluices for different types of estuaries are summed up, at the same time, corresponding methods are given to solve these problems, and a few successful examples are also given. The idea of comprehensive regulation and utilization of estuaries is put forward, and some proposals for solution of sediment deposition in this kind of estuaries are made. 展开更多
关键词 sediment deposition lower courses of tidal sluices CUT-OFF comprehensive utilization river channel RUNOFF
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Morphometric and geological conditions for sediment accumulation in the Udava River, Outer Carpathians, Slovakia 被引量:1
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作者 BARABAS Dusan BONA Jan +1 位作者 KLEIN Daniel BALAZOVICOVA Lenka 《Journal of Geographical Sciences》 SCIE CSCD 2017年第8期981-998,共18页
The accumulation of sediment in river channels is a phenomenon that is not only influenced by the channel morphology, but also by the physical and geographical character- istics and the endogenous and exogenous proces... The accumulation of sediment in river channels is a phenomenon that is not only influenced by the channel morphology, but also by the physical and geographical character- istics and the endogenous and exogenous processes taking place in the catchment. This paper presents an analysis of the impact the changes in lithological conditions have on the morphological and morphometric parameters of the Udava River channel and their relation to the channel accumulation forms representative of the river's longitudinal profile as well as of its planform. Results document when accumulation forms occur and what is their spatial dis- tribution within the longitudinal and cross-sectional river profiles. More resistant structures created sections with a lower degree of sedimentation, while in depression segments the degree of sedimentation was higher. With the increase in longitudinal slope, the impact of channel width on the average channel bar size increased. Also a difference in the accumula- tion was observed between the left and right bank which could be possibly explained by the impact of Coriolis force. 展开更多
关键词 Flysch Carpathians Udava river river channel channel bar ACCUMULATION longitudinal profile
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CALCULATION OF FLOW FIELD AND ANALYSIS OF SPAWNING SITES FOR CHINESE STURGEON IN THE DOWNSTREAM OF GEZHOUBA DAM 被引量:8
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作者 FU Xiao-li LI Da-mei JIN Guo-yu 《Journal of Hydrodynamics》 SCIE EI CSCD 2007年第1期78-83,共6页
The Chinese sturgeon (Acipenser Sinensis) is one of the unique and important fishery resources in China. Since the construction of the Gezhouba Dam, the traditional migration route of the sturgeon has been blocked; ... The Chinese sturgeon (Acipenser Sinensis) is one of the unique and important fishery resources in China. Since the construction of the Gezhouba Dam, the traditional migration route of the sturgeon has been blocked; consequently, the length of natural spawning sites is reduced from 800 km in the past to less than 5 km at present. As an endangered species, the Chinese sturgeon has become one of the most conserved aquatic species. In this article, the flow field of its spawning states in the downstream of Gezhouba Dam was simulated and analyzed using N-S equations and k-ε turbulence model. Volume Of Fluid (VOF) method with the Finite Volume Method (FVM) was used to simulate the water-air two-phase flow to examine the computed area. On the basis of the ecological-hydraulic characteristics of Chinese sturgeon, the features of the flow field were investigated to provide theoretical support for the proper management of the Three Gorges Reservoir. 展开更多
关键词 Chinese sturgeon (Acipenser Sinensis) FiniteVolume Method (FVM) Volume Of Fluid (VOF) naturalspawning site three-dimensional river channel
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NUMERICAL STUDY FOR EVOLUTION OF COHERENT VORTEX IN UNIDIRECTIONAL OSCILLATORY BOUNDARY LAYER OVER SAND RIPPLES 被引量:2
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作者 Bai Yu-chuan Institute for Sedimentation on River and Coast Engineering,Tianjin University, Tianjing 300072, China Ng Chiu-On Department of Mechanical Engineering, The University of Hongkong, Hongkong, China 《Journal of Hydrodynamics》 SCIE EI CSCD 2002年第4期88-94,共7页
Ripples are widely formed in river channels and coastal regions, the bed-forms and vortex dynamics accompanied with them are quite important because they are responsible for frictions and sediment transports. The cohe... Ripples are widely formed in river channels and coastal regions, the bed-forms and vortex dynamics accompanied with them are quite important because they are responsible for frictions and sediment transports. The coherent vortex structure play a key role in the process, so how to model them is needed for understanding the formation process of sand ripples. In this paper, 2D Large-Eddy-Simulation (LES) was used to predict the flow structure and the dynamics of coherent vortex. The numerical results show a complete process of formation, evolvement and disappearance for the cases of unidire ctional and oscillatory flows over symmetic and asymmetric ripples 展开更多
关键词 oscillatory flow large eddy simulation sand ripple river channel
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Basin-Scale Sand Deposition in the Upper Triassic Xujiahe Formation of the Sichuan Basin, Southwest China: Sedimentary Framework and Conceptual Model 被引量:10
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作者 谭秀成 夏青松 +5 位作者 陈景山 李凌 刘宏 罗冰 夏吉文 杨家静 《Journal of Earth Science》 SCIE CAS CSCD 2013年第1期89-103,共15页
The Upper Triassic Xujiahe (须家河) Formation in the Sichuan (四川) Basin, Southwest China is distinctive for the basin-scale sand deposition. This relatively rare sedimentary phenomenon has not been well interpre... The Upper Triassic Xujiahe (须家河) Formation in the Sichuan (四川) Basin, Southwest China is distinctive for the basin-scale sand deposition. This relatively rare sedimentary phenomenon has not been well interpreted. Here we addressed this issue by discussing sedimentary framework and conceptual model. Analysis of sedimentary setting implied that the basin received transgression during the deposition. It had multiple provenance supplies and river networks, as being surrounded by old- lands in multiple directions including the north, east and south. Thus, the basin was generally charac-terized by coastal and widely open and shallow lacustrine deposition during the Late Triassic Xujiahe period. This is similar to the modern well-known Poyang (鄱阳) Lake. Therefore, we investigated the framework and conceptual model of the Sichuan Basin during the Xujiahe period with an analogue to the Poyang Lake. Results show that the conceptual model of the deposition can be divided into transgressive and regressive stages. The first, third and fifth mem- bers of the formation are in transgressive stage and the deposits are dominated by shore and shallow lacustrine mud. In contrast, the deposition is mainly of braided river channel sand deposits during the regressive stage, mainly including the second, fourth and sixth members of the formation. The sand deposited in almost the entire basin because of the lateral migration and forward moving of the cross networks of the braided rivers. The multiple alternations of short and rapid transgression and relatively long regression are beneficial to the basin-scale sand deposition. Thus, the main channel of the braided river and its extensional areas are favorable for the development of hydrocarbon reservoir. This provides practical significance to the reservoir evaluation and exploration. In addition, the results also justify the relatively distinctive sedimentary phenomenon in the study area and may also have im- plications for understanding the large-scale sand deposition elsewhere. 展开更多
关键词 basin-scale sand deposition coastal and widely open lake sedimentary framework sedimentary conceptual model channel of braided river Upper Triassic Xujiahe Formation Sichuan Basin.
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