نتایج جستجو برای: river bed

تعداد نتایج: 131107  

Journal: :international journal of environmental research 0
t.h. choo department of civil engineering, pusan national university, jangjeon-dong, geumjeong-gu, busan, 609-735, south korea s.j. maeng chungbuk national university, jangjeon-dong, geumjeong-gu, south korea h.c. yoon department of civil engineering, pusan national university, jangjeon-dong, geumjeong-gu, busan, 609-735, south korea d.m. kim department of civil engineering, pusan national university, jangjeon-dong, geumjeong-gu, busan, 609-735, south korea s.c. kim department of civil engineering, pusan national university, jangjeon-dong, geumjeong-gu, busan, 609-735, south korea

this study proposed a new discharge estimation method using a mean velocity formula derived from chiu’s 2d velocity formula of probabilistic entropy concept and the river bed shear stress of channel. in particular, we could calculate the mean velocity, which is hardly measurable in flooding natural rivers, in consideration of several factors reflecting basic hydraulic characteristics such as ri...

2010
Jonathan M. Nelson Yasuyuki Shimizu Sanjay Giri Richard R. McDonald

Uncertainties in flood stage prediction and bed evolution in rivers are frequently associated with the evolution of bedforms over a hydrograph. For the case of flood prediction, the evolution of the bedforms may alter the effective bed roughness, so predictions of stage and velocity based on assuming bedforms retain the same size and shape over a hydrograph will be incorrect. These same effects...

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...

2011
JAMES C. BRICE Thomas B. Nolan

_ ----------____-_.__________.__..____._... Introduction.-.._._..___.__.___...'_.._.._.___...___ Pleistocene and Recent deposits .......L.............. North Loup River valley near Elba._____._..___._ North Loup River valley near Burwell..__.__._.__ North Loup River valley downstream from Brewster. North Loup River valley upstream from Brewster... South Loup River valley near Cumro. ___________...

2005
Franco Bagnoli Duccio Fanelli Luca Sguanci

The interaction between a fluid and a granular material plays a crucial role in a large class of phenomena such as river-bed morphology and river transport of sediments, aeolian sand dunes and ripples dynamics. Standard models involve deterministic continuum equations or, alternatively, Lattice Boltzmann and Lattice Gas Cellular Automata. We here introduce a toy-model to address the issue of ri...

H Bonakdari M Moazamnia

Flow-rate measurement in rivers under different conditions is required for river management purposes including water resources planning, pollution prevention, and flood control. This study proposed a new discharge estimation method by using a mean velocity derived from a 2D velocity distribution formula based on Tsallis entropy concept. This procedure is done based on several factors which refl...

M. Zamani Faradonbe S. Eagderi

The relationship between some habitat factors and fish assemblage was analyzed in the Taleghan River, Alborz Province, Iran. Fish specimens from thirty-three sites were sampled by electrofishing device in October 2014. The habitat parameters, including elevation (m), water depth (cm), river width (m), river slope (%), current velocity (m.s-1), number of large stone (> 15 cm), average stone diam...

2011
Arvind Singh Stefano Lanzoni Peter R. Wilcock Efi Foufoula-Georgiou

[1] Migrating bed forms strongly influence hydraulics, transport, and habitat in river environments. Their dynamics are exceedingly complex, making it difficult to predict their geometry and their interaction with sediment transport. Acoustic instrumentation now permits high-resolution observations of bed elevation as well as flow velocity. We present a space-time characterization of bed elevat...

2008
MARC HONNORAT XIJUN LAI

A numerical method for model parameters identification is presented for a river model based on a finite volume discretization of the bidimensional shallow water equations. We use variational data assimilation to combine optimally physical information from the model and observation data of the physical system in order to identify the value of model inputs that correspond to a numerical simulatio...

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