نتایج جستجو برای: Suspended sediment yield

تعداد نتایج: 248054  

Journal: :iranian journal of earth science 0
a.v. gusarov russia, republic of tatarstan, kazan, 420008, kremlevskaya str., 18, kazan university, faculty of geography and ecology

the offered approach is based on the establishment of the functional dependence between river water discharge (q) and suspended ms ,in a number of observations, which noticeably differs from the mean value (r) of subsequent allocated period(s). the earliest period anthropogenic component during the subsequent period(s) is the difference between an actual suspended sediment yield and its hypothe...

1985
ROBERT B. THOMAS

The "Selection At List Time" (SALT) scheme controls sampling of concentration for estimating total suspended sediment yield. The probability of taking a sample is proportional to its estimated contribution to total suspended sediment discharge. This procedure gives unbiased estimates of total suspended sediment yield and the variance of the estimate while automatically emphasizing sampling at h...

زینی وند, حسین, حقی زاده, علی , میرزایی, سمیه ,

In this study, the ability of spatially distributed hydrological WetSpa model for simulation of suspended sediment concentration in a daily time step was investigated. Hydro-climate daily data for a period of 7 years including: precipitation, temperature, evaporation, discharge and suspended sediment and three basic basic digital maps of DEM, soil texture and land use, with the cell size of 25 ...

This study is aimed at estimating suspended sediment load in watersheds using hydro-climatic factors with the intent to determine spatial and temporal variations of sediment yield in Qarah Su drainage basin, Ardebil Province. For this study, data from seven rain gauge and hydrometric stations during a 22-year period were used. The research was based on statistical regression analysis between va...

2017
Jose Ramon B. Cantalice Luis da Silva Souza Yuri Jacques Agra Bezerra Silva Sergio M.S. Guerra Alex Mauricio Araújo Douglas Monteiro Cavalcante Cinthia Maria Cordeiro Atanazio Cruz Silva

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...

1999
ROBERT B. THOMAS

SALT (Selection At List Time) is a variable probability sampling scheme that provides unbiased estimates of suspended sediment yield and its variance. SALT performs better than standard schemes which are estimate variance. Sampling probabilities are based on a sediment rating function which promotes greater sampling intensity during periods of high sediment yield. When preparing to monitor usin...

2010
John J. Ramírez-Avila James L. Martin

The Town Creek watershed is located in the Southeastern Plains Ecoregion in Mississippi. Its total area covers 1,769 km and represents approximately 50% of the upper Tombigbee River basin area contributing to the Aberdeen Pool on the Tennessee-Tombigbee Waterway. The sediment yield from the watershed attributes to the estimated 320,000 T yr of deposition in Aberdeen pool, where annual dredging ...

Journal: :محیط زیست طبیعی 0
سادات فیض نیا استاد دانشکده منابع طبیعی، دانشگاه تهران، ایران گلاله غفاری کارشناس ارشد آبخیزداری و عضو گروه پژوهشی مرکز خدمات تخصصی آب و خاک و gis معاونت پژوهش جهاد دانشگاهی واحد کردستان، ایران کیوان کریمی زاده کارشناس ارشد آبخیزداری و عضو گروه پژوهشی مرکز خدمات تخصصی آب و خاک و gis معاونت پژوهش جهاد دانشگاهی واحد کردستان، ایران منیرالسادات طباطبایی زاده دانشجوی کارشناسی ارشد مدیریت مناطق بیابانی، دانشکده منابع طبیعی، دانشگاه تهران، ایران

there is a lack of accurate and correct information about erosion in iran. moreover, there is a big difference between measurements and estimations. sediment is also an important environmental problem which pollutes water physically and chemically and therefore, sediment problem is usually studied as environmental problems. estimation of sediment yield of drainage basins is important for preven...

2007
S. Grauso

An application of regression relationships depending on geomorphic parameters is proposed to predict the amount of the average annual suspended sediment yield at different sections of the drainage network. Simple and multiple regression relationships, utilising the drainage density and the hierarchical anomaly index as independent variables, based on data from 20 river basins of different size ...

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...

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