نتایج جستجو برای: suspended sediment yield was estimated. to select best model

تعداد نتایج: 11352688  

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...

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...

رمضانی پور, الیاس, مساعدی, ابوالفضل, مصداقی, منصور,

The phenomena of erosion, sediment transport and sedimentations have tremendously destructive effects on environment and hydraulics structures. In general, sediment transportation depends on river discharges, but the proposed equations inherited with large errors. To evaluate the suspended sediment loads and an optimized model on them, in this research, data were collected from some sub-watersh...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه علامه طباطبایی 1390

over the past decades a number of approaches have been applied for forecasting mortality. in 1992, a new method for long-run forecast of the level and age pattern of mortality was published by lee and carter. this method was welcomed by many authors so it was extended through a wider class of generalized, parametric and nonlinear model. this model represents one of the most influential recent d...

Journal: :مرتع و آبخیزداری 0
علی سلاجقه علی فتح آبادی

correct estimation of suspended sediment transported by a river is an important practice in water structure design, environmental problems and water quality issues. conventionally, sediment rating curve used for suspended sediment estimation in rivers. in this method discharge and sediment discharge or concentration related using regression relation that generally is exponential model. respect ...

Extended abstract 1- Introduction The phenomena of erosion, sediment transport, and sedimentations have tremendously destructive effects on the environment and hydraulics structures. In general, the sediment transportation depends on river discharges, but the proposed equations inherited serious errors.  The estimation of suspended sediment load (SSL) is one of the most important factors in r...

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...

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 ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تحصیلات تکمیلی علوم پایه زنجان - دانشکده شیمی 1391

in this thesis a calibration transfer method is used to achieve bilinearity for augmented first order kinetic data. first, the proposed method is investigated using simulated data and next the concept is applied to experimental data. the experimental data consists of spectroscopic monitoring of the first order degradation reaction of carbaryl. this component is used for control of pests in frui...

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...

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