نتایج جستجو برای: sediment entry
تعداد نتایج: 108618 فیلتر نتایج به سال:
Sediment transport relates to suspended sediment and bedload. The suspended sedi‐ ment plays the most important role on the land-ocen sediment flux. On the other hand, the bedload should be considered in order to assess the impacts of dams on sediment transport and sediment yield. Recent effects of dam construction have been widely reported. The sediment load has been reduced by more than 75% f...
pure rockfill dams have been found specific attention in watershed management and flood control, recently. in addition to hydraulic specific features, one of the important advantages of these structures is their consistency with nature and environment. normally, floods are accompanied with high sediment loads which may enter the body of dam. when flow through dam body governed by hydraulic grad...
today fingerprinting techniques are increasingly adopted as an alternative and more direct and reliable means of assembling sediment source information. one of the principal assumptions of sediment fingerprinting is that potential catchment sediment sources can be distinguished on the basis of their physical, geochemical and biological properties or fingerprint properties. however, while the so...
By far, different models for determining the relationship between the flow rate and amount of precipitation have been developed. many models are based on regression models with limited assumptions. one of the most common methods for estimating sediment of rivers is sediment rating curve. for better estimation of the amount of sediment based of sediment curve rating equation, it is possible t...
A light attenuation sensor system (LASS) for measurements in waters is described in this paper. The LASS records irradiance at multiple levels in the water column to provide a measure of the diffuse light attenuation coefficient which is strongly affected by suspended sediment. Dimensional analysis and geometric optical theory are used to relate the irradiance attenuation to sediment properties...
Disposable solid-phase microextraction fibers (SPMEs) were used to measure the availability of 2,4,6-trinitrotoluene (TNT) and its two primary transformation products, 2-amino-4,6-dinitrotoluene (2ADNT) and 4-amino-2,6-dinitrotoluene (4ADNT). The SPMEs (85-microm polyacrylate) and sediment-dwelling oligochaetes (Tubifex tubifex) were exposed to TNT-spiked sediment, to TNT-spiked sediment amende...
Elevated suspended sediment concentrations in fluvial environments have important implications for system ecology and even small concentrations may have serious consequences for sensitive ecosystems or organisms, such as freshwater pearl mussels (Margaritifera margaritifera). Informed decision making is therefore required for land managers to understand and control soil erosion and sediment del...
The accumulation kinetics of the amphipod Diporeia sp. for sediment-sorbed polycyclic aromatic hydrocarbon (PAH) congeners were measured where the contact time between the PAH congeners and the sediments varied between 3 and 150 d. Diporeia were exposed to a reference sediment dosed with two radiolabeled PAHs (phenanthrene and pyrene) and to sediments dosed with the two radiotracers and a mixtu...
Increasing sediment input into coastal environments is having a profound influence on shallow marine habitats and associated species. Coral reef ecosystems appear to be particularly sensitive, with increased sediment deposition and re-suspension being associated with declines in the abundance and diversity of coral reef fishes. While recent research has demonstrated that suspended sediment can ...
[1] Mechanistic models for sediment transport on hillslopes are needed for applications ranging from landscape evolution to debris-flow hazards. Progress has been made for soil-mantled landscapes; however, little is known about sediment production and transport in bedrock landscapes that often maintain a patchy soil mantle, even though slopes exceed the angle of repose. Herein we investigate th...
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