نتایج جستجو برای: suspended sediment yield

تعداد نتایج: 248054  

Journal: :Continental shelf research 2007
David K Ralston Mark T Stacey

Field observations of flow and sediment transport in a tributary channel through intertidal mudflats indicate that suspended sediment was closely linked to advection and dispersion of a tidal salinity front. During calm weather when tidal forcing was dominant, high concentrations of suspended sediment advected up the mudflat channel in the narrow region between salty water from San Francisco Ba...

Journal: :مرتع و آبخیزداری 0
محسن یوسفی کارشناس ارشد آبخیزداری، دانشکدة منابع طبیعی و کویرشناسی، دانشگاه یزد، ایران فاطمه برزگر عضو هیئت علمی دانشکدة کشاورزی دانشگاه پیام نور، ایران

suspended sediment estimation is an important factor from different aspects including, farming, soil conservation, dams, aquatic life, as well as various aspects of the research. there are different methods for suspended sediment estimation. this study aims to estimate suspended sediment using feed forward neural network with error back propagation with levenberg-marquardt back propagation algo...

Journal: :مرتع و آبخیزداری 0
سید حمید رضا صادقی استاد گروه آبخیزداری، دانشکدة منابع طبیعی، دانشگاه تربیت مدرس شیرکوه ابراهیمی محمدی استادیار گروه مرتع و آبخیزداری، دانشکدة منابع طبیعی، دانشگاه کردستان کامران چپی استادیار گروه مرتع و آبخیزداری، دانشکدة منابع طبیعی، دانشگاه کردستان

the behavior of suspended sediment during flood events is not only a function of energy conditions, i.e. sediment is stored at low flow and transported under high flow conditions, but also is related to the variations in sediment supply and sediment depletion. these changes in sediment availability result in so-called hysteresis effects. therefore, hysteresis pattern analysis is of great import...

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The sediment load that is transported by rivers can create numerous problems such as sedimentation in the reservoir and storage capacity reduction, developed load in the rivers, destruction of structures along the river and transfer of pollution. Therefore, an accurate estimate of the sediment load in rivers is absolutely essential for river engineering, reservoir design, sediment transportatio...

2017
Yuyan Zhou Jun Xu Weihua Xiao Jianhua Wang Ya Huang Heng Yang

Climate change is expected to have stronger effects on water resources in higher latitude regions. Despite intensive research on possible hydrological responses in those regions to a warmer environment, our knowledge on erosion and sediment yield induced by the climate change in high-latitude headwaters is still limited. In this study, we estimated suspended sediment yields from 2021 to 2050 in...

The variable and complex nature of the sediment load of rivers has led that the estimation of sediment entering the reservoirs and the production of long term sediment, for determining the lifetime of the structures encounter with the problem. Application of sediment rating curves is one of the most common methods for estimating the suspended sediment load of rivers. Regardless of the accuracy ...

Journal: :Journal of environmental quality 2014
T N Williamson V G Christensen W B Richardson J W Frey A C Gellis K A Kieta F A Fitzpatrick

Documenting the effects of agricultural land retirement on stream-sediment sources is critical to identifying management practices that improve water quality and aquatic habitat. Particularly difficult to quantify are the effects from conservation easements that commonly are discontinuous along channelized streams and ditches throughout the agricultural midwestern United States. Our hypotheses ...

Journal: :Journal of environmental quality 2010
R Mukundan D E Radcliffe J C Ritchie L M Risse R A McKinley

Thousands of stream miles in the southern Piedmont region are impaired because of high levels of suspended sediment. It is unclear if the source is upland erosion from agricultural sources or bank erosion of historic sediment deposited in the flood plains between 1830 and 1930 when cotton farming was extensive. The objective of this study was to determine the source of high stream suspended sed...

EXTENDED ABSTRACT      The land use change of watersheds has entailed many impacts on the processes of erosion and sediment yield over the time, and has caused the loss of soil quality and fertility. On the other hand, an increase in the sediment generation and its accumulation would reduce the capacity of the reservoirs. In this respect, the purpose of this study was to evaluate the effects o...

2005
Daniel L. Calhoun Todd C. Rasmussen

Differential pressure transducers can be used to monitor the suspended-sediment concentration in a water column. Suspended sediments with densities greater than water increase the fluid density, which is determined by measuring the fluid pressure change between two depths. Lewis and Rasmussen (1999) used a densimetric technique under controlled conditions to determine suspended-sediment concent...

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