نتایج جستجو برای: river

تعداد نتایج: 83553  

Journal: :Brazilian journal of biology = Revista brasleira de biologia 2001
D C Rossa F A Lansac-Tôha C C Bonecker L F Velho

The abundance of cladocerans recorded in plankton samples from the littoral regions of two environments (Baía River and Guaraná lake), the Upper Paraná River floodplain and some limnological variables important in controlling their abundance were investigated at three sites in the lake and two in the river, from March/93 to January/94. Abundance was highest in the lake, chiefly during high wate...

2003
H. Yang

The Haihe River basin is one of the most developed regions in China. With the rapid economic development and associated increases in water demand, the river basin has been enduring increasing water stress. Water for the ecosystem use has been compromised and the environment has been deteriorating. Water shortage has become a bottleneck to the further development of the economy and grain product...

2002
MARTIJN J. BOOIJ Martijn J. Booij

Important characteristics of an appropriate river basin model, intended to study the effect of climate change on basin response, are the spatial and temporal resolution of the model and the rainfall input. The effects of input and model resolution on extreme discharge of a large river basin are assessed to give some indication on appropriate resolutions. A simple stochastic rainfall model and a...

Journal: :The Journal of heredity 2000
P Bloomer N D Impson

The Berg River redfin (Pseudobarbus burgi) is a critically endangered endemic cyprinid from South Africa. We investigated mitochondrial DNA control region variation among specimens representative of five populations drawn from two adjacent river systems. Phylogenetic analyses, a minimum spanning network, and an analysis of molecular variance underscore the pronounced genetic separation of redfi...

2006
Pawel Topa

Rivers can be treated as transportation networks which supply or collect and remove certain resources from the surrounding environment. A positive feedback between environment and river network both reshapes the configuration of the terrain and produces dynamically stable web of river channels. Anastomosing rivers exemplify such interactions very clearly. In case of this specific type of river,...

Journal: :The Science of the total environment 2004
M H Paller C H Jagoe H Bennett H A Brant J A Bowers

Average methylmercury levels in five Savannah River tributary streams, sampled 11 times over 2 years (0.170 ng/l), were nearly twice as high as in the Savannah River (0.085 ng/l). Total mercury levels in the tributaries (2.98 ng/l) did not differ significantly from the river (2.59 ng/l). All of the tributaries drained extensive wetlands that would be expected to support comparatively high rates...

2006
Yonas Gebeyehu Tesfaye Mark M. Meerschaert Paul L. Anderson

[1] The generation of synthetic river flow samples that can reproduce the essential statistical features of historical river flows is useful for the planning, design, and operation of water resource systems. Most river flow series are periodically stationary; that is, their mean and covariance functions are periodic with respect to time. This article develops model identification and simulation...

2013
Fengzhou Wang Baohua Xu Mengxi Xu Jianqiang Shi Lang Jia Chenming Li

Large-Scale Particle Image Velocimetry (LSPIV) is an effective method for the measurement of the river surface flow velocity. For the wide cross-section river, in the near-field area of river surface image there are small and clear targets. But the flow tracers are almost invisible in the far-field area because of the resolution limit of one single video camera, which makes it difficult to comp...

2015
Liu Jie

Ro-Ro transportation refers to a way of maritime transportation that uses Ro-Ro to bring goods and shipment together. Developments of Ro-Ro transport at home and abroad are outlined, and development process of China’s Ro-Ro transport is reviewed. The development and status of Ro-Ro transport of Yangtze River are analyzed in detail. Based on survey research, due to the change of road structure o...

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...

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