Download or read book Handbook for Predicting Stream Meander Migration written by Peter Frederick Lagasse and published by Transportation Research Board. This book was released on 2004 with total page 107 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Predicting Meander Migration written by Jean-Louis Briaud and published by . This book was released on 2001 with total page 39 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Predicting Meander Migration of the Sacramento River CA written by Jessica Louise Thomas and published by . This book was released on 2001 with total page 402 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Prediction of Meander Migration Based on Large scale Flume Tests in Clay written by Namgyu Park and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Meander migration is a complex and dynamic process of the lateral movement of a river due to erosion on one bank and deposition on the opposite bank. As a result, the channel migrates in a lateral direction, which might be a major concern for the safety of bridges during their life span of 75 years. Although there are several existing models for predicting meander migration of a river, none of them are based on the physical model tests on a specific type of soil. A total of eight flume tests are conducted to develop a prediction equation of meander migration in clay. The test results of migration rate follow a hyperbolic function, and spatial distribution of the maximum migration distance is fitted with the Pearson IV function. The proposed equations of the initial migration rate and the maximum migration distance, obtained by a multiple regression technique, are validated with the laboratory data. A new methodology for risk analysis is developed to process a number of predicted channel locations based on each future hydrograph generated in such a way that all the hydrographs have the same probability of occurrence. As the output from risk analysis, a CDF map is created for a whole river representing a general trend of migration movement along with the probability associated with new location of the river. In addition, a separate screen is generated with a CDF plot for a given bridge direction so that bridge engineers can read a specific migration distance along the bridge corresponding to the target risk level (e.g. 1 %). The newly developed components through this research are incorporated with the other components in the MEANDER program which is a stand-alone program and the final outcome of the research team. Verification study of the MEANDER program is conducted with full-scale field data at the Brazos River at SH 105, Texas. The prediction results matched quite well with the measured field data. However, a more extensive verification study for other sites is highly recommended.
Download or read book Establish Guidance for Soils Properties based Prediction of Meander Migration Rate written by and published by . This book was released on 2007 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt: Several solutions for predicting the movement of meanders have been proposed in the past. This report shows these solutions to be unreliable. The solution outlined in this report considers soil erodibility as an independent parameter influencing meander migration. Other conventional parameters such as flow velocity, meander radius of curvature, river width, and others are part of the proposed solution. Through a combination of well-instrumented large-scale flume tests, quality numerical simulations, and fundamental laboratory erosion tests, a simple and reliable solution is developed.
Download or read book A Hydrograph based Prediction of Meander Migration written by Wei Wang and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Meander migration is a process in which water flow erodes soil on one bank and deposits it on the opposite bank creating a gradual shift of the bank line over time. For bridges crossing such a river, the soil foundation of the abutments may be eroded away before the designed lifetime is reached. For highways parallel to and close to such a river, the whole road may be eaten away. This problem is costing millions of dollars to TxDOT in protection of affected bridges and highway embankments. This research is aimed at developing a methodology which will predict the possible migration of a meander considering the design life of bridges crossing it and highways parallel to it. The approaches we use are experimental tests, numerical simulation, modeling of migration, risk analysis, and development of a computer program. Experimental tests can simulate river flow in a controlled environment. Influential parameters can be chosen, adjusted, and varied systematically to quantify their influence on the problem. The role of numerical simulation is to model the flow field and the stress field at the soil-water interface. Migration modeling is intended to integrate the results of experimental tests and numerical simulations and to develop a model which can make predictions. The Hyperbolic Model is used and its two major components M[subscript]max equation and [tau][subscript]max equation are developed. Uncertainties in theparameters used for prediction make deterministic prediction less meaningful. Risk analysis is used to make the prediction based on a probabilistic approach. Hand calculation is too laborious to apply these procedures. Thus the development of a user friendly computer program is needed to automate the calculations. Experiments performed show that the Hyperbolic Model matches the test data well and is suitable for the prediction of meander migration. Based on analysis of shear stress data from numerical simulation, the [tau] [subscript]max equation was derived for the Hyperbolic Model. Extensive work on the simplification of river geometry produced a working solution. The geometry of river channels can be automatically simplified into arcs and straight lines. Future hydrograph is critical to risk analysis. Tens of thousands of hydrographs bearing the same statistical characteristics as in history can be generated. The final product that can be directly used, the MEANDER program, consists of 11,600 lines of code in C++ and 2,500 lines of code in Matlab, not including the part of risk analysis. The computer program is ready for practice engineers to make predictions based on the findings of this research.
Download or read book Prediction of Meander Migration for Four Rivers in Texas at Roadway Crossings written by Fahmidah Ummul Ashraf and published by . This book was released on 2013 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt: River meandering can endanger the hydraulic structures by lateral expansion and down-valley translation of meander bends. In this study, the RVR Meander model was used to predict the meander migration for four bridge crossings in the state of Texas, USA. The bridge crossings are SH 105 at the Brazos River, FM 787 at the Trinity River, US 90 at the Nueces River and SH 63 at the Sabine River. A widely used migration coefficient approach developed by Ikeda et al. (1981) was adopted, which relates migration rate linearly to vertically-averaged near bank excess velocity through the use of a coefficient of bank erosion. This study estimates erosion coefficient values for eroded banks from measured long term migration rates and computed near bank excess velocities. The values of erosion coefficients are calibrated using the RVR Meander model with the least prediction error. The predicted planform evolution using the model suggests that the migration coefficient approach used in the model can capture the growth of meander bends if they do not change the migration direction. In general, the model can predict migration well in lateral and downstream direction. This study also attempts to examine the extent to which erosion coefficient depends on resistance of bank material to fluvial erosion. Erosion Function Apparatus (EFA) erodibility values represent the resistance of bank material to fluvial erosion. At the upstream bends adjacent to the road crossings for which both erosion coefficients and EFA erodibility values were obtained, it was found that erodibility values follow the trend of erosion coefficients, unless significant hydraulic or geomorphic changes occurred in the watershed and in the channel due to the human activities. It opens up the possibility that erosion coefficients may be estimated directly from the bank material properties instead of using the historical maps. This suggests that for long term (several decades) meander migration riparian vegetation is not a major controlling factor. This hypothesis requires further testing with data sets from other road crossings over rivers.
Download or read book Evaluating River Restoration Design Using a Meander Migration Model on the Trinity River California written by Alex Jeremiah Young and published by . This book was released on 2006 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Methodology for Predicting Channel Migration written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This report documents and presents the results of a study to develop a practical methodology to predict the rate and extent of channel migration in proximity to transportation facilities. The principal product of this research was a stand-alone Handbook for predicting stream meander migration using aerial photographs and maps. The Handbook is published separately as NCHRP Report 533 and can be purchased through the TRB bookstore (trb.org/bookstore). The Handbook deals specifically with the problem of incremental channel shift and provides a methodology for predicting the rate and extent of lateral channel shifting and down valley migration of meanders.
Download or read book Observation Method to Predict Meander Migration and Vertical Degradation of Rivers written by Axel M. Montalvo Bartolomei and published by . This book was released on 2014 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt: Meander migration and vertical degradation of river bed are processes that have been studied for years. These two erosion controlled processes consist of the gradual change of the geometry of the river due to the flow of water eroding the soil. This erosion may cause a shift that could be a threat to existing bridges, highways, and useful lands. Different methods have been proposed to make predictions of the behavior of rivers with respect to these processes. Many of these methods are used to predict the migration rate and the final position of the bankline or centerline of a river, assuming that the erosion rate is constant for a certain time. However, most of these methods ignore one of the three general processes of meander migration and vertical degradation: geometry, flow, and soil. Therefore, there is need for a method that can accurately predict the amount of erosion that may occur in rivers. Six different sites in Texas were selected for this project. Four of the selected rivers have meander migration problems, and two rivers have vertical degradation problems. Each river has shown erosion problems that have been a threat to the bridges, roads or farm lands. A new method, called the Observation Method, was developed to predict meander migration and vertical degradation by using geometry, water flow, and soil erodibility. Aerial photos and maps from different years were obtained to study the change of the geometry of the rivers. River hydrographs were obtained from the U.S. Geological Survey to estimate the river velocity from daily flow. Soil samples from each site were obtained for laboratory testing, using the Erosion Function Apparatus. A code was written in MATLAB and Excel to estimate the critical velocity by using a model based on the erosion function obtained from the erosion tests. It is important to know where the river was and its history to be able to predict where the river will be. The erosion of each river from the six sites was estimated using the model and predictions were made for 10 years after the last observation for each case. This method proved to be a simple and quick way to obtain results for the movement of one point of the river. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/152490
Download or read book Meander Migration Prediction of the Clark Fork River at Grant Kohrs Ranch Montana written by Claudia Elena Castro and published by . This book was released on 2005 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Quantifying the Connections Between Flow Bar Deposition and Meander Migration in Large Gravel bed Rivers written by Candice R. Constantine and published by . This book was released on 2006 with total page 382 pages. Available in PDF, EPUB and Kindle. Book excerpt: Predicting channel migration is a key component of designing plans for river management and restoration. Fundamentally, the lateral migration rate depends on the rate of excavation of the outer bank toe. This rate is a function of bank resistance to erosion, flow velocity, bend geometry, and sediment transport and storage. Although it is certain that all these variables play some role in determining migration rates in gravel-bed rivers, the importance of sediment storage in particular has not been thoroughly investigated. Currently employed meander migration models are driven by curvature effects on near-bank flow and account for differences in bank erodibility through use of a calibrated bank erosion coefficient. Despite increasing application of such models to sensitive management problems, it remains unclear how the coefficient varies with properties of the channel and to what extent it incorporates the effects of changes in bed-material storage on migration rate.
Download or read book Mechanics and Modeling of River Meander Migration written by Eric Walsh Larsen and published by . This book was released on 1995 with total page 728 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Channel Meander Migration in Large scale Physical Model Study written by Po Hung Yeh and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A set of large-scale laboratory experiments were conducted to study channel meander migration. Factors affecting the migration of banklines, including the ratio of curvature to channel width, bend angle, and the Froude number were tested in the experiments. The effect of each factor on the evolution of channel plan form was evaluated and quantified. The channel bankline displacement was modeled by a hyperbolic function with the inclusion of an initial migration rate and a maximum migration distance. It is found that both the initial migration rate and maximum migration distance exhibit a Gaussian distribution along a channel bend. Correlations between the distributions and the controlling parameters were then studied. Two sets of equations were developed for predicting the initial migration rate and the maximum migration distance. With the initial migration rate and maximum migration distance being developed as a function of geometric and flow parameters, a hyperbolic-function model can be applied to estimate the bankline migration distance. The prediction of channel centerline migration was also developed in this study. The channel centerline was represented with a combination of several circular curves and straight lines. Each curve with the radius of curvature and bend angle was used to describe the channel bend geometry. HEC-RAS was applied to estimate the flow hydraulic properties along the channel by adjusting the channel bed slope. The intersections of two consecutive centerlines were found to be the inflection points of the centerline migration rate. Phase lag to the bend entrance was measured and correlated with the bend length and water depth. The migration rate between two successive inflection points demonstrated a growth and decay cycle. A sine function was used to model the centerline migration rate with regression analysis of the measurement data. The method was applied to four sites of four natural rivers in Texas. The results showed that the prediction equation provides agreeable results to the centerline migration of natural rivers.
Download or read book Water Security and Sustainability written by Chandrashekhar Bhuiyan and published by Springer Nature. This book was released on 2021-02-22 with total page 311 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains selected peer-reviewed papers presented in the International Conference Down To Earth 2019, and is focused on Water Security and Sustainability. The topics covered in this book include sustainability of water resources, geospatial modelling and hydro-informatics, extreme hydrology (drought and flood), adaptation to climate-change impacts, vulnerability-risk-reliability-resilience, and hydrological risks in north-east India. The book also discusses innovative techniques and technologies for water resources assessment and management. Enriched with numerous case studies covering diverse topics, the book can be valuable for students, researchers, as well as industry professionals interested in water resources assessment, management and sustainable development.
Download or read book River Dynamics written by Bruce L. Rhoads and published by Cambridge University Press. This book was released on 2020-04-29 with total page 544 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rivers are important agents of change that shape the Earth's surface and evolve through time in response to fluctuations in climate and other environmental conditions. They are fundamental in landscape development, and essential for water supply, irrigation, and transportation. This book provides a comprehensive overview of the geomorphological processes that shape rivers and that produce change in the form of rivers. It explores how the dynamics of rivers are being affected by anthropogenic change, including climate change, dam construction, and modification of rivers for flood control and land drainage. It discusses how concern about environmental degradation of rivers has led to the emergence of management strategies to restore and naturalize these systems, and how river management techniques work best when coordinated with the natural dynamics of rivers. This textbook provides an excellent resource for students, researchers, and professionals in fluvial geomorphology, hydrology, river science, and environmental policy.
Download or read book Meander Migration Rate written by J.-L. Briaud and published by . This book was released on 2002 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt:
