نتایج جستجو برای: fine sediment load
تعداد نتایج: 290264 فیلتر نتایج به سال:
Sediment transport by surficial flow likely occurs on Titan. Titan is thought to have a volatile cycle, such as on Earth and likely in the past on Mars, which would entail surficial liquid flow. And surficial flow is implied in interpretations of Cassini–Hyugens data as showing fluvial channels, which would require sediment transport by surficial flow to form the observable features. We present...
1. Increased fine sediment deposition is a prevalent threat to stream biodiversity and has been shown to impact stream-breeding salamanders negatively. However, their complex life histories make it difficult to determine which stage is affected. 2. We conducted field experiments from 26 August to 11 September 2010 and 11 October to 11 November 2010 in two southern Appalachian headwater streams ...
Median grain sizes on riverbeds range from boulders in uplands to silt in lowlands; however, rivers with ~1–5mm diameter bed sediment are rare. This grain size gap also marks an abrupt transition between graveland sand-bedded reaches that is unlike any other part of the fluvial network. Abrupt gravel-sand transitions have been attributed to rapid breakdown or rapid transport of fine gravel, or ...
Fine inorganic sediment (≤ 2mm) is a major non-point source pollutant in streams. While some fine sediment in streams is natural, loads in human-impacted streams often exceed their capacity to flush these sediments during high flows. Regardless of the source, the negative effects of increased levels of fine sediment in streams are realized in all biotic components of stream ecosystems from micr...
The rivers sediment load is determined using hydrologic methods. In the statistical methods, by measuring the rivers discharge and suspended sediment load in a long-term period, the relationships between the suspended sediment load and discharge is obtained. The aim of this study is to compare different estimation methods of suspended load and select the most appropriate relationship for the pr...
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...
The application of “Modified Einstein Procedure” is recommended by the Specialized Committee on Sediment, Iranian Ministry of Energy. However, this method has not been applied to any river in the country. It is the purpose of this study to investigate the total sediment load of the Karun and Karkheh rivers at Ahwas and Hamidieh stations. The graphical calculations of the method are very complic...
The Afon Goch (Anglesey, UK) is a short (12 km source to estuary) stream highly contaminated by acid mine drainage (AMD) throughout its length, due to past-mining at the head of the stream. Metal distribution is strongly controlled by the pH, which increases downstream particularly at confluences with two unpolluted tributaries. A pH increase causes precipitation of metals, primarily Fe as hydr...
A model is presented that simulates the effects of streamflow and sediment transport on survival of salmonid embryos incubating in spawning gravels in a natural channel. Components of the model include a 6-yr streamflow record, an empirical bed load-transport function, a relation between transport and infiltration of sandy bedload into a gravel bed, effects of fine-sediment infiltration on grav...
2 Research Hydrologist, Pacific Southwest Forest and Range Experiment Station, Forest Service, U.S. Department of Agriculture, Arcata, Calif. Abstract: Large floods in northwestern California in the past two decades have mobilized extensive areas of valley floors, removed streamside trees, and widened channels. Channel cross sections were surveyed to illustrate an hypothesis on the linkage betw...
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