نتایج جستجو برای: bed rivers

تعداد نتایج: 67553  

ژورنال: علوم آب و خاک 2017
خالدی درویشان, عبدالواحد, روشان, سید حسین, سلیمانی, کریم, وهاب زاده, قربان,

Sand and gravel mining from the most of our country rivers causes morphological, hydrological and geomorphological changes in these rivers. This study investigates the effects of removal of sand and gravel from the river bed on sedimentological features of Zaremrood River in Mazandaran province. For this purpose, by determining four sections before and four sections after the sand removing poin...

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Darab Plain is among region that in there formed several alluvial fans because presence of situation and climate change, and can mention to Katoeh, Rigabad and Chenar alluvial fans. In this research is tried to using of Geology and Topographic Maps, Arial Image ana Field survey analysis are discussed  Factors affecting the establishment and evolution of this alluvial fans. Result showed that Ka...

2011
Michael P. Lamb Jeffrey A. Nittrouer David Mohrig John Shaw

[1] Sediment flux from rivers to oceans is the fundamental driver of fluvio-deltaic morphodynamics and continental margin sedimentation, yet sediment transport across the river-to-marine boundary is poorly understood. Coastal rivers typically are affected by backwater, a zone of spatially decelerating flow that is transitional between normal flow upstream and the offshore river plume. Flow dece...

Journal: :Geophysical Research Letters 2022

Looping patterns, where channels divide and reconnect further downstream, are widespread in natural rivers. Here, we build an extensive dataset of different gravel-bed sand-bed rivers around the world encompassing a wide range physiographic sedimentological conditions. Field data show existence quasi-universal relations for anabranches length when scaled with bankfull hydraulic geometry variabl...

2003
Mattia Zaramella Aaron I. Packman Andrea Marion

[1] Hydrodynamic exchange between a stream and its bed plays an important role in solute transport in rivers. Stream-subsurface exchange is known to occur due to several different mechanisms and different approaches have been used to model the resulting solute transport, but there has been little investigation of the ability of the various models to represent specific exchange processes. This w...

2016
Douglas J. Jerolmack David Mohrig

Bed form evolution remains dynamic even in the special case of steady, uniform flow. Data from the sandy, braided North Loup River, Nebraska, show that roughness features on the channel bottom display a statistical steady state and robust scaling that are maintained through the collective interactions of transient (shortlived) bed forms. Motivated by such field data, and laboratory observations...

2007
B. Gharabaghi

Increased construction activity and associated receiving water concerns in the Greater Toronto Area has prompted this study to advance our knowledge on cohesive sediment transport processes in rivers and lake environments. Flow characteristics in a rotating circular flume at the National Water Research Institute (NWRI), Burlington, Ontario were studied using a computational fluid dynamics (CFD)...

2016
Michael P. Lamb Fanny Brun Brian M. Fuller

The hydraulics of steep mountain streams differ from lower gradient rivers due to shallow and rough flows, energetic subsurface flow, and macro-scale form drag from immobile boulders and channel and bed forms. Heightened flow resistance and reduced sediment transport rates in steep streams are commonly attributed to macro-scale form drag; however, little work has explored steep river hydrodynam...

2013
M K Verma M Z Qamar

The Himalayan Rivers due to their steep bed and side slopes, narrow width and fragile geology of the region carry huge amount of sediment with them. Many runof-river hydro power projects are coming up on these rivers and suspended sediment enters into the power intake of these projects. Desilting chambers are provided to remove / minimize the suspended sediment from water conductor system. The ...

2003
C. Donnelly H. Chanson

A tidal bore impacts significantly on the estuarine ecosystem, although little is known on the flow field, mixing and sediment motion beneath tidal bores. In the absence of detailed field measurements, a quasi steady flow analogy was applied to investigate an undular tidal bore with inflow Froude numbers 1.6 and 1.25. Experimental results indicated that rapid flow redistributions occur beneath ...

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