نتایج جستجو برای: river

تعداد نتایج: 83553  

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In addition to Erodibility of sediment particles in river increase river sediment load, they are important factors in morphological changes. In the rivers that erodibility is high, trend of morphological changes are intensive that in this case, river is unstable. On the contrary, it will lead stability and low changes of the river. Study area of this research is Saraskanchay that has been locat...

Journal: :caspian journal of environmental sciences 2008
a. h. charkhabi m. sakizadeh

studies have showed the river siahroud is the main contributor to the present pollution of anzali wetland in guilan. therefore, this study was initiated to evaluate the spatial distribution of metals pollution on the river siahroud sediments in guilan.surfacial river sediment samples along this river were taken during five consecutive seasons at eight sampling stations and analyzed for availabi...

Journal: :Anais da Academia Brasileira de Ciencias 2012
Luiz D Lacerda Wanderley R Bastos Marcelo D Almeida

Changes in hydrochemistry and Hg distribution in the Madeira River from Porto Velho to the confluence with the Amazon River were studied in two cruises in 1997 and 2002. Water conductivity was similar in both periods, but the pH was significantly higher in 2002, in particular along the middle reaches of the river. Total suspended matter concentrations also increased from 1997 to 2002 along the ...

2017
Nurul Ruhayu Mohd Rosli Khairun Yahya

The study of river water quality plays an important role in assessing the pollution status and health of the water bodies. Human-induced activities such as domestic activities, aquaculture, agriculture and industries have detrimentally affected the river water quality. Pinang River is one of the important rivers in Balik Pulau District that supplies freshwater for human consumption. A total of ...

2010
Tsz-Yam Lau

Fragmentary river segments have to be joined appropriately before becoming useful to addressing transportation problems like route planning and pollutant tracking. We suggest the induced terrain approach to complete the job with high accuracy and efficiency. By first approximating a terrain compatible with the partial river segment and height information, and then deriving a river network from ...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2000
W J Trush S M McBain L B Leopold

Rivers around the world are being regulated by dams to accommodate the needs of a rapidly growing global population. These regulatory efforts usually oppose the natural tendency of rivers to flood, move sediment, and migrate. Although an economic benefit, river regulation has come at unforeseen and unevaluated cumulative ecological costs. Historic and contemporary approaches to remedy environme...

Journal: :جغرافیا و مخاطرات محیطی 0
زهرا گوهری محمد تاج بخش محبوبه سربازی سید ناصر نعیمی قصابیان

1. introduction the analysis of drainage networks is a powerful tool to detect recent tectonic activity and uplift, as river channels are very sensitive to changes in the parameters that control their shapes and. climate changes, tectonics and lithology affect river equilibrium conditions and hence, river geometry. a river is in dynamic equilibrium when erosion keeps pace with sedimentation and...

Journal: :international journal of advanced biological and biomedical research 2014
mohammad bagherian marzouni ali mohammad akhoundalib hadi moazed nematollah jaafarzadeh javad ahadian

karun river is the largest and most watery river in iran. this river is the longest river which located just inside iran and ahvaz metropolis drinking water supplied from karun river as well (fa.alalam.ir). karun river as the main source of water treatment plants in ahvaz, like most surface waters affected by various contaminants which caused changes in water quality of the river (www.aww.co.ir...

2016
Yuting Fan Yaning Chen Qing He Weihong Li Yun Wang Jun Xu

Understanding runoff generation and dynamics is the basis for water resource management, while water isotopic ratios are a potential tool for studying the mechanism on a large scale. In this paper, spatial variations of δ18O and δD of river water and their sources within a large region of the Tarim River were investigated. The results showed obvious spatial variations of both water isotope valu...

Journal: :Environmental toxicology and chemistry 2002
David R Ownby Michael C Newman Margaret Mulvey Wolfgang K Vogelbein Michael A Unger L Felipe Arzayus

Prior studies suggest that field-collected fish (Fundulus heteroclitus) from a creosote-contaminated Superfund site (Atlantic Wood Industries site, Elizabeth River, VA, USA) have enhanced tolerance to local, contaminated sediments. This study was designed to test whether other populations in the Elizabeth River at less contaminated sites also show similar tolerance and whether this tolerance is...

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