نتایج جستجو برای: river flow

تعداد نتایج: 557015  

2005
V. T. HOM

Each winter and early spring, the Northeast River Forecast Center (NERFC) faces the challenge of forecasting river stage and flow for ice affected rivers. “Stage versus flow” relationships tend to be in error and there is a lack of real-time information about the nature of the ice cover. The NERFC is investigating methods to forecast river stage and flow for ice-affected rivers because in times...

2015
Masahiro Ryo Yuichi Iwasaki Chihiro Yoshimura Oliver C. Saavedra V. Zhong-Ke Gao

Alteration of the spatial variability of natural flow regimes has been less studied than that of the temporal variability, despite its ecological importance for river ecosystems. Here, we aimed to quantify the spatial patterns of flow regime alterations along a river network in the Sagami River, Japan, by estimating river discharge under natural and altered flow conditions. We used a distribute...

2006
A. J Desai

Floods of high magnitude are one of the major problems in the north-eastern region of India. Heavy flooding causes abrupt changes in the flow pattern of the rivers. The present paper deals with the study of three northern bank tributaries of the Brahmaputra river, namely Jia-Bhareli, Puthimari and Pagladiya. The river Brahmaputra shows significant amount of erosion and deposition in the basin. ...

2007
M. Firat

The use of Artificial Intelligence methods is becoming increasingly common in the modeling and forecasting of hydrological and water resource processes. In this study, applicability of Adaptive Neuro Fuzzy Inference System (ANFIS) and Artificial Neural Network (ANN) methods, Generalized Regression Neural Networks (GRNN) and Feed 5 Forward Neural Networks (FFNN), for forecasting of daily river f...

2011
Lori A. Sprague Robert M. Hirsch Brent T. Aulenbach

Changes in nitrate concentration and flux between 1980 and 2008 at eight sites in the Mississippi River basin were determined using a new statistical method that accommodates evolving nitrate behavior over time and produces flow-normalized estimates of nitrate concentration and flux that are independent of random variations in streamflow. The results show that little consistent progress has bee...

Journal: :مهندسی عمران فردوسی 0
جواد مظفری امیر صمدی سید اسدالله محسنی موحد داود داودمقامی

recognizing of river flow pattern, deposition and erosion areas in meanders is highly important. despite the limitations of the physical models in laboratory investigation of flow pattern in meanders, mathematical models can be helpful. in this research, rsm and les turbulence models have been compared on sharp river bend of a laboratory flume using fluent software. the laboratory flume is a sh...

2004
DAVID L. DETTMAN KARL W. FLESSA PETER D. ROOPNARINE BERND R. SCHÖNE DAVID H. GOODWIN

We describe a new method for the calculation of river flow that uses the oxygen isotope composition of bivalve mollusk shells that grew in the river-water/seawater mixing zone of the Colorado River estuary. Sclerochronological techniques are used to identify tidally-induced, fortnight-scale bundles of daily growth increments within shell cross-sections. These fortnightly markers are used to est...

2012
M. C. Bowers W. W. Tung J. B. Gao

[1] Distributional analysis of river discharge time series is an important task in many areas of hydrological engineering, including optimal design of water storage and drainage networks, management of extreme events, risk assessment for water supply, and environmental flow management, among many others. Having diverging moments, heavy-tailed power law distributions have attracted widespread at...

2002
Daqing Yang Douglas L. Kane Larry D. Hinzman Xuebin Zhang Tingjun Zhang Hengchun Ye

[1] The long-term (1935–1999) monthly records of temperature, precipitation, stream flow, river ice thickness, and active layer depth have been analyzed in this study to examine Lena River hydrologic regime and recent change. Remarkable hydrologic changes have been identified in this study. During the cold season (October–April), significant increases (25–90%) in stream flow and decrease in riv...

2006
A. O. Cardoso

Several studies indicate that there is a relationship between the climatic variability in the South American continent and alterations of the position and intensity of the heat sources in the equatorial region. The El Niño phenomenon can influence the precipitation over some regions of South America such as the Brazilian Northeast, Amazonia, South of Brazil and Uruguay. Over 80% of Brazil’s ene...

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