نتایج جستجو برای: coarse bed rivers

تعداد نتایج: 97968  

2001
Peter Molnar

Although regional climates throughout much of the world appear to have become more arid in late Cenozoic time, sedimentation rates, and therefore presumably erosion rates, have increased. For sustained erosion of elevated terrain, at least where glaciers are not the major erosive agent, rivers must incise. Therefore bed-load transport by rivers should be a rate-limiting process in erosion. Theo...

2008
Michael Bliss Singer

Grain-size distributions of bed material sediment in large alluvial rivers are required in various scientific and management applications, but characterizing gravel beds in navigable rivers is hampered by difficulties in sediment extraction. The newly developed and preliminarily tested sampler reported here can extract sediment from a range of riverbeds. The 36 × 23 × 28 cm stainless steel toot...

2014
Michele Guala Arvind Singh

This paper considers the problem of spatiotemporal bed topography evolution and sediment transport estimation in rivers with migrating bed forms of different types and sizes, in statistical equilibrium conditions. Instead of resorting to bed form classification, we propose to evaluate the evolution of multiscale bed topography as the integral of unit contributions defined through a space-time F...

2016
R. D. Williams R. Measures D. M. Hicks J. Brasington

Numerical morphological modeling of braided rivers, using a physics-based approach, is increasingly used as a technique to explore controls on river pattern and, from an applied perspective, to simulate the impact of channel modifications. This paper assesses a depth-averaged nonuniform sediment model (Delft3D) to predict the morphodynamics of a 2.5 km long reach of the braided Rees River, New ...

Journal: :caspian journal of enviromental sciences 0

rivers are important water resources for human life, but sometimes cause irreparable damages. the flood plains are fertile terrains which are endangered by flood. flood hazard mapping is one of the basic methods in flood fighting. in order to decline flood damages, the simulation of the hydraulic behavior of the rivers during flood occurrence is very important. in this study, areas that are flo...

Journal: :The Science of the total environment 2013
D El Azzi J Viers M Guiresse A Probst D Aubert J Caparros F Charles K Guizien J L Probst

For centuries, many Mediterranean catchments were covered with vineyards in which copper was widely applied to protect grapevines against fungus. In the Mediterranean-type flow regime, brief and intense flood events increase the stream water discharge by up to 10 times and cause soil leaching and storm runoff. Because vineyards are primarily cultivated on steep slopes, high Cu fluxes are discha...

Journal: :Water 2023

The transport of a non-uniform bed load in river is complicated process and has enormous implications on the sediment flux anomalous riverbed evolution. To investigate characteristics related particle interactions, real-time monitoring system was developed to determine instant rate grain composition load. Doppler Velocimetry used synchronously measure fluctuating velocity high frequency. A tota...

2000
F. Métivier Y. Gaudemer

We compare the present-day sediment discharge (solid phase) of some of the largest rivers in Asia to the average discharge deduced from the mass accumulated in several sedimentary basins during the Quaternary. There is a very good correlation, especially for the largest rivers: the Ganges–Brahmaputra, the Changjiang, the Huanghe and, to a lesser extent, the Indus and the Zhujiang. This suggests...

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