نتایج جستجو برای: suspended sediment yield

تعداد نتایج: 248054  

Journal: :desert 2015
ali talebi a. bahrami m. mardian j. mahjoobi

managers always consider the precise estimation of sediments in watersheds due to various conditions, such assoil and water resources management, construction, infrastructure and economical and social issues. in this condition,an optimized determination of sediment rating equation (typical method until now for sediment yield estimation) isessential to investigate sediment yield in rivers. in th...

Journal: :Hydrology and Earth System Sciences 1999

2004
S L Yang Z Shi H Y Zhao P Li S B Dai A Gao

The surface erosion area in the Yangtze River basin increased from 364×10 3 km 2 in the 1950s to 707×10 3 km 2 in 2001 due to a great increase in population. Based on the regression relationship between surface erosion area and population, the surface erosion area was predicted to be about 280×10 3 km 2 at the beginning of the 20 th century. The sediment yield, which increased by about 30% duri...

Journal: :نشریه علمی - پژوهشی هیدرولوژی کاربردی 0
fatemeh shokrian sari agricultural sciences and natural resources university k. shahedi

estimate of sediment load is required in a wide spectrum of water resources engineering problems. the nonlinear nature of suspended sediment load series necessitates the utilization of nonlinear methods to simulate the suspended sediment load. in this study artificial neural networks (anns) are employed to estimate daily suspended sediment load. two different ann algorithms, multi layer percept...

2000
Robert B. Thomas

A probability sampling method called SALT (Selection At List 'Time) has been developed for collecting and summarizing data on delivery of suspended sediment in rivers. It is based on sampling and estimating yield using a suspended-sediment rating curve for high discharges and simple random sampling for low flows. The method gives unbiased estimates of total yield and variance. The technique has...

2004
Scott A. Wright David H. Schoellhamer

Human activities within a watershed, such as agriculture, urbanization, and dam building, may affect the sediment yield from the watershed. Because the equilibrium geomorphic form of an estuary is dependent in part on the sediment supply from the watershed, anthropogenic activities within the watershed have the potential to affect estuary geomorphology. The Sacramento River drains the northern ...

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 ...

برزگری, فاطمه, دستورانی, محمدتقی,

Accurate estimation of suspended sediment in rivers is very important from different aspects including agriculture, soil conservation, shipping, dam construction and aquatic research. There are different methods for suspended sediment estimation. In the present study to evaluate the ability of time-series models including Markov and ARIMA in predicting suspended sediment and to compare their re...

Fatemeh Shokrian, K. Shahedi,

Estimate of sediment load is required in a wide spectrum of water resources engineering problems. The nonlinear nature of suspended sediment load series necessitates the utilization of nonlinear methods to simulate the suspended sediment load. In this study Artificial Neural Networks (ANNs) are employed to estimate daily suspended sediment load. Two different ANN algorithms, Multi Layer Perce...

Journal: :desert 2010
h. memarian khalilabad s. feiznia k. zakikhani

abstract erosion and sedimentation are the most complicated problems in hydrodynamic which are very important in water-related projects of arid and semi-arid basins. for this reason, the presence of suitable methods for good estimation of suspended sediment load of rivers is very valuable. solving hydrodynamic equations related to these phenomenons and access to a mathematical-conceptual model ...

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