نتایج جستجو برای: sediment

تعداد نتایج: 36882  

2004
Hua Lu Christopher Moran Ian Prosser Murugesu Sivapalan

Sediment delivery ratio (SDR) is traditionally defined as the fraction of upland gross erosion that is transported out of a defined area, e.g., a plot or catchment. It is, effectively, an index of sediment transport efficiency. Previously, it is treated as an empirically-lumped parameter used as a mechanism for compensating for sediment deposition within a catchment area. In this paper, we prop...

2012

A sediment model has been developed to simulate the Sediment Oxygen Demand (SOD) and sediment nutrient fluxes after a sudden input of Particulate Organic Matter (POM). Compared with previous sediment models, the main model advancements are the use of a continuous function to represent the kinetics of POM diagenesis and inclusion of the biomass content in POM diagenesis. Laboratory experiments a...

2007
Hyoseop Woo Pierre Y. Julien

Current knowledge of the mechanics of alluvial channels depends very largely on calculations of turbulent shear stresses; typical examples are the beginning of motion of sediment particles and sediment transport in alluvial channels. If shear stress can be well defined in clear-water flows, comparatively little is known about shear stresses in sediment-laden flows. Einstein and Chien (1955) pro...

ژورنال: آبخیزداری ایران 2019
dehghan, Hadi, memariyan, Hadi,

The sediment load estimation is essential for watershed management and soil conservation strategies. The sediment rating curve is the most common approach for estimating the sediment load when the observed sediment records are not available. With regard to the measurement errors and the limitation of available data, the sediment rating curve has a degree of uncertainty which should be accounted...

Journal: :مرتع و آبخیزداری 0
کاظم نصرتی دانشیار گروه جغرافیای طبیعی، دانشکده علوم زمین، دانشگاه شهید بهشتی، ایران سعیده جلالی دانش آموخته ژئومورفولوژی، دانشکده علوم زمین، دانشگاه شهید بهشتی، ایران

identifying sediment sources is one of important factors in selecting of appropriate method of erosion control and soil conservation. the main objective of this study is to estimateuncertainty and contribution of forest roads to sediment yield in ziarat drainage basin, gorgan city using geochemical tracers. for this purpose, 47 soil samples were collected from different sources with different l...

Journal: :environmental resources research 0
a zare gariz phd candidate, department of rangeland and watershed management, yazd university, iran a talebi associate professor, department of rangeland and watershed management, yazd university, iran

in this study, the process-based watershed model, soil and water assessment tool (swat), was used for simulating hydrology and sediment transport in the gharesou watershed and for identifying critical areas of soil erosion and water pollution. after model calibration and uncertainty analysis using sufi-2 (sequential uncertainty fitting, ver. 2) method, the outputs of the calibrated model were u...

Journal: :Archives of environmental contamination and toxicology 2003
J F McCarthy L W Burrus V R Tolbert

The accumulation of 14C-benzo(a)pyrene (BaP) sorbed to sediment was examined in fathead minnows (Pimephales promelas) to compare uptake from sediment with a high organic carbon (OC) content (7.7%), to that with a low OC content (2%). Ingestion of sediments was quantified by co-labeling the sediment with 141Cerium, which was not assimilated by the fish. Results of this study indicated that (1) s...

2002
L. Collins

Bed surface particle size patchiness may play a central role in bedload and morphologic response to changes in sediment supply in gravel-bed rivers. Here we test a 1-D model (from Parker ebook) of bedload transport, surface grain size, and channel profile with two previously published flume studies that documented bed surface response, and specifically patch development, to reduced sediment sup...

Extended abstract Introduction The present study was performed to investigate the effects of slope percentage and land use type on the produced sediment by an artificial rainfall simulator in Kakasharaf watershed, a branch of Karkhe watershed (Lorestan province).   Methodology The rainfall simulator used in this research was designed and constructed by the Soil Conservation and...

2017
Dongfeng Xie Cunhong Pan Xiuguang Wu Shu Gao Zhengbing Wang

The research objective is to investigate the variations of sediment transport in outer Changjiang Estuary and adjacent Hangzhou Bay, induced by the decline of Changjiang River sediment discharge and massive land reclamation in the last three decades. A synchronous hydrographic survey was conducted along two transects (at the bay-mouth and outer Changjiang Estuary, respectively) during the sprin...

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