نتایج جستجو برای: river bed
تعداد نتایج: 131107 فیلتر نتایج به سال:
Local bridge scour is caused by the interference of bridge piers with the flow of water and is characterized by the formation of scour holes. Local scour occurs at a bridge pier when the local flow field is strong enough to remove bed materials. Several variables affect the scour depth including the flow intensity, the relative flow depth, the pier-width, and the properties of the river bed mat...
The U.S. Army Corps of Engineers’ Hydrologic Engineering Center’s River Analysis System (HEC-RAS) is a widely used software application for performing one-dimensional and two-dimensional steady and unsteady flow river hydraulics calculations, sediment transport-mobile bed modeling, and water quality analysis. User’s of HEC-RAS have often unique applications including the coupling with other sof...
fractionation studies on the sediment samples provide valuable information on the nature of the metals bound to the sediments. thirty three sediment samples of river adyar were collected during two seasons and speciation study was carried out. the industrial and domestic effluents are directed into the river course at many points in the middle and lower of the adyar river. to ascertain the exte...
Sediment dynamics were investigated in Lake Maggiore, Italy, with field observations from October to mid-December 2012. Three moorings were deployed in Pallanza Bay, a small embayment on the western side of the lake near the Toce River inflow, to measure temperature and currents throughout the water column and suspended sediment concentration (SSC) was estimated with acoustic instrumentation. R...
Sedimentary dispersal systems with fine-grained beds are common, yet the physics of sediment movement within them remains poorly constrained. We analyze sediment transport data for the best-documented, fine-grained river worldwide, the Huanghe (Yellow River) of China, where sediment flux is underpredicted by an order of magnitude according to well-accepted sediment transport relations. Our theo...
[1] A new data set of bimodal subaqueous channel bed sediments was analyzed for longitudinal patterns in grain size. It yielded two interesting observations: (1) separate fining trends in d50 exist for gravel and fines that overlap for 175 river kilometers, and (2) this overlap in fining trends results in a protracted (nonabrupt) gravel to sand transition. These suggest bed patchiness that is i...
An experimental study of the preservation of cross-sets during the migration of current ripples under aggrading and non-aggrading conditions was conducted in order to test the modi®ed Paola±Borgman theory for distribution of cross-set thickness as a function of distribution of bed-wave height. In a series of ̄ume experiments, the geometry and migration characteristics of the ripples did not var...
The dynamics of river bed evolution are known to be notoriously complex affected by near-bed turbulence, the collective motion of clusters of particles of different sizes, and the formation of bedforms and other large-scale features. In this paper, we present the results of a study aiming to quantify the inherent nonlinearity and complexity in gravel bed dynamics. The data analyzed are bed elev...
This paper uses the results of river suspended sediment flux (SSF) analysis to propose a new hydrological method for quantitatively estimating the river bed and drainage basin (sheet erosion, rill and gully erosion) components of total erosion intensity in river basins. The suggested method is based on the establishment of the functional power connection between mean monthly water discharges (W...
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