نتایج جستجو برای: amount of sediment

تعداد نتایج: 21168937  

2005
Jonathan Malarkey Alan G. Davies

The 1DV two-layer model of oscillatory sheet flow of Malarkey et al. (2003) which was developed for a single grain size has been modified to include grain fractions. The model includes a suspension layer above a sheet-flow layer consisting of prescribed profiles of concentration and velocity. Since this model keeps track of the total sediment in the water column through the wave cycle it is ide...

Journal: :مرتع و آبخیزداری 0
علی گلکاریان استادیار دانشکدة منابع طبیعی و محیط زیست دانشگاه فردوسی داود داودی مقدم دانشجوی کارشناسی ارشد آبخیزداری دانشکدة منابع طبیعی و علوم دریایی دانشگاه تربیت مدرس سید امیر نقیبی دانشجوی کارشناسی ارشد آبخیزداری دانشکدة منابع طبیعی و علوم دریایی دانشگاه تربیت مدرس مسعود عشقی زاده دانشجوی دکتری آبخیزداری، دانشکدة منابع طبیعی و کویرشناسی دانشگاه یزد

soil erosion is undoubtedly one of the most important problems in natural areas and has a devastating impact on grassland ecosystems. the present study was conducted to assess the ability of rangeland hydrology and erosion model for estimating sediment yield on rangeland’s hill slopes in dry regions at shahid noori paired watershed of kakhk. rhem is a mathematical, distribution and physical mod...

Journal: :journal of water sciences research 2010
a khosronejad

in the present paper, a 3d numerical model has been applied to predict the flow hydrodynamics around power intakes within the dez dam reservoir. the dez dam is a 203 m high, double arch concrete dam which is constructed by italians in 1962. since then, sedimentation in reservoirhas continued and since the dam does not have bottom outlet, the reservoir bed level is raising by a rate of about 2.5...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه ارومیه - دانشکده کشاورزی 1393

چکیده کنه تارتن دو لکه ای tetranychus urticae koch یکی از چندخوارترین آفات شناخته شده محصولات کشاورزی دنیا به حساب می آید. در این بررسی جمعیت تخم و مراحل فعال این کنه در شرایط آلودگی طبیعی و مصنوعی در برگ های 8 رقم لوبیا در سال 1392 در گلخانه و مزرعه تحقیقاتی دانشکده کشاورزی دانشگاه ارومیه موردمطالعه قرار گرفت. آزمایش به صورت طرح کاملاً تصادفی برای شرایط مزرعه در10 تکرار و برای شرایط گلخانه ای...

2009
Jeremy A. Sharp

This Technical Note (TN) describes herein an approach to estimating the amount of sediment that passes through an estuary inlet in the Gulf of Mexico in terms of sediment yield per year. Estimated values for the Weeks Bay estuary and the approach taken to obtain the values are provided as guidance for other estuaries. The TN is in direct support of the Mississippi State University lead project ...

ژورنال: علوم آب و خاک 1997
موسوی, سیدفرهاد, جلالیان, احمد, صمدی بروجنی, حسین , محمدزاده, احمد ,

One of the most vital problems in the storage and utilization of surface waters for drinking, flood control, hydropower, and agricultural purposes is that of sedimentation in reservoirs and subsequent decline of dam lifetime. The useful lifetime of a dam is defined as the time necessary for approximately 80% of the volume of its initial capacity to be filled by sediments washed in by water. It ...

2016
Bao Son Trinh Brian Reid Kevin Hiscock

BACKGROUND Sorption and biodegradation are the primary processes of organic pollution remediation in aquatic and soil/sediment environments. While researchers have substantially reported their findings regarding these processes, little attention has been given to description of experimental apparatus. This technical paper aims to present the development and detailed design of a fixed-bed column...

2013
Beth N. Orcutt Douglas E. LaRowe Jennifer F. Biddle Frederick S. Colwell Brian T. Glazer Brandi Kiel Reese John B. Kirkpatrick Laura L. Lapham Heath J. Mills Jason B. Sylvan Scott D. Wankel C. Geoff Wheat

The vast marine deep biosphere consists of microbial habitats within sediment, pore waters, upper basaltic crust and the fluids that circulate throughout it. A wide range of temperature, pressure, pH, and electron donor and acceptor conditions exists-all of which can combine to affect carbon and nutrient cycling and result in gradients on spatial scales ranging from millimeters to kilometers. D...

Journal: :Philosophical transactions. Series A, Mathematical, physical, and engineering sciences 2016
Dominic A Hodgson Michael J Bentley James A Smith Julian Klepacki Keith Makinson Andrew M Smith Kevin Saw Reed Scherer Ross Powell Slawek Tulaczyk Mike Rose David Pearce Matt Mowlem Peter Keen Martin J Siegert

Accumulations of sediment beneath the Antarctic Ice Sheet contain a range of physical and chemical proxies with the potential to document changes in ice sheet history and to identify and characterize life in subglacial settings. Retrieving subglacial sediments and sediment cores presents several unique challenges to existing technologies. This paper briefly reviews the history of sediment sampl...

In a natural ecosystem, land exploitation and change in environmental conditions, particularly changes in vegetation and land use effects on hydrological responses such as floods and erosion and sediment and ultimately causing heavy social-economic losses. Then, prediction of effect of land use changes on flood situation in the future decades and sedimentation of watersheds will be the way to d...

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