نتایج جستجو برای: sediment transport

تعداد نتایج: 305291  

2007
Nira L. Salant Carl E. Renshaw Francis J. Magilligan James M. Kaste Keith H. Nislow Arjun M. Heimsath

We investigate the use of the short-lived fallout radionuclide beryllium-7 ( Be; t1/2 = 53·4 days) as a tracer of medium and coarse sand (0·25–2 mm), which transitions between transport in suspension and as bed load, and evaluate the effects of impoundment on seasonal and spatial variations in bed sedimentation. We measure Be activities in approximately monthly samples from point bar and stream...

Journal: :Computers & Geosciences 2006
Guy Simpson Sébastien Castelltort

This paper presents a mathematical model coupling water flow and sediment transport dynamics that enables calculating the changing surface morphology through time and space. The model is based on the shallow water equations for flow, conservation of sediment concentration, and empirical functions for bed friction, substrate erosion and deposition. The sediment transport model is a non-capacity ...

Sediment Bypass Tunnels (SBTs) are deviant channels that convey the current containing sediments from the upstream of the reservoir to the downstream of the dam. In this research, by applying submerged plates on the entrance of a 90-degree diversion channel for sediment transport, the effect of hydraulic parameters of flow and changes in the angle of plates on sediment transport and deviated fl...

H. Torabi R. Dehghani

Sediment transport constantly influences river and civil structures and the lack ofinformation about its exact amount makes management efforts less effective. Hence,achieving a proper procedure to estimate the sediment load in rivers is important. We usedsupport vector machine model to estimate the sediments of the Kakareza River in LorestanProvince and the results were compared with those obta...

The efficiency and economical performance of sewer systems is an essential issue in urban drainage. The need for sewers to carry sediment has been recognized for many years. One of the main problems in designing sewerage systems is the sediment deposition. Sedimentation in sewers occurs regularly according to the alternating natural flow. The present study investigates the hydraulic characteris...

2004
GREGORY E. TUCKER

Long-term average rates of channel erosion and sediment transport depend on the frequency–magnitude characteristics of flood flows that exceed an erosion threshold. Using a Poisson model for rainfall and runoff, analytical solutions are developed for average rates of stream incision and sediment transport in the presence of such a threshold. Solutions are derived and numerically tested for thre...

2011
J. Taylor Perron

[1] The numerical methods used to solve nonlinear sediment transport equations often set very restrictive limits on the stability and accuracy of landscape evolution models. This is especially true for hillslope transport laws in which sediment flux increases nonlinearly as the surface slope approaches a limiting value. Explicit‐time finite difference methods applied to such laws are subject to...

2015
Zhiguo He Peng Hu Liang Zhao Gangfeng Wu

Breaching of earthen or sandy dams/dunes by overtopping flow and waves is a complicated process with strong, unsteady flow, high sediment transport, and rapid bed changes in which the interactions between flow and morphology should not be ignored. This study presents a depth-averaged two-dimensional (2D) coupled flow and sediment transport model to investigate the flow and breaching processes w...

2010
Andrea S. Ogston

A long-term goal of our sediment transport and accumulation investigations is to link sedimenttransport processes to the formation and preservation of event beds in sediment deposits. The general aim of this project is to investigate how forcing processes affect the sediment-transport dynamics that act to import or export fine-grained sediment in intertidal regions. We strive to understand how ...

2016
Ian E. Floyd S. Jarrell Smith Steve H. Scott Gary L. Brown

BACKGROUND: Inland waterways provide many benefits to society but serve primarily as conduits of water and sediment. Bank erosion, channel sedimentation, and reservoir infilling remain challenges to the effective management of waterways. Reservoirs have a limited service life, associated in part with the reduced capacity caused by infilling. The USACE manages more than 600 reservoirs, many of w...

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