نتایج جستجو برای: temperature and river flow

تعداد نتایج: 17007071  

Journal: :international journal of environmental research 2013
w. huang s. yano j.m. zhang y.r. wang

the environmental and ecological issues in the flow-reduced river reach are very serious and arereceiving increasingly attention. in this study, we investigate the temporal and spatial changes in δ13c and δ15n of periphyton and isotopic relationship between periphyton and the endangered fish (ayu, plecoglossusaltivelis) in a flow-reduced river reach in japan. much of the spatial and temporal va...

2011
P. Carling

This chapter presents a range of key concepts that enable natural rivers to be understood as complex flows of water and sediment that interact and often result in changes to the channel shape. The implications for salmon fisheries and invertebrates are also considered. Rivers are linear features and so it might be supposed that the flow hydraulics would be unidirectional and relatively simple t...

Journal: :مرتع و آبخیزداری 0
کاظم نصرتی استادیار دانشکده علوم زمین، دانشگاه شهید بهشتی، ایران

the term hydrological drought is applied to represent low water levels in streams, reservoirs and lakes as well as a low groundwater level. base flow index (bfi) as one of low flow indices gives the ratio of base flow to total flow and investigates basin’s ability to store and release of water in drought periods. the objectives of this study were to determine bfi and to validate this index in d...

Journal: :journal of hydraulic structures 2014
mojtaba rafiee ali mohammad akhond ali hadi moazed steve w. lyon nemat jaafarzadeh

human activities in the recent years have considerably increased the rate of water pollution in many regions of the world. in this case study, the main sources of wastewater discharging into the gargar river were identified. using river and point source flow rates and water quality parameters measured along the river, the river water quality was simulated using a commonly used, one-dimensional ...

Journal: :journal of tethys 0

the morphological river evolution at long-time (centuries and even millennia) and large spatial scale (watersheds of several square kilometres) can be described by means of simplified 1d models, able to simulate the variation of bed elevation and grain size composition at non-detailed scales, involving a reduced computational effort. the erosion and deposition phenomena acting along rivers can ...

A.R Mardookhpour

In order to determine hydrological behavior and water management of Sepidroud River (North of Iran-Guilan) the present study has focused on stream flow prediction by using artificial neural network. Ten years observed inflow data (2000-2009) of Sepidroud River were selected; then these data have been forecasted by using neural network. Finally, predicted results are compared to the observed dat...

2011
S. E. NULL J. R. LUND

This paper examines and ranks restoration alternatives for improving fish habitat by evaluating tradeoffs between fish production and restoration costs. Optimization modelling is used to maximize out‐migrating coho salmon (Oncorhynchus kisutch) from a natal stream and is applied as a case study in California’s Shasta River. Restoration activities that alter flow and water temperature conditions...

پایان نامه :دانشگاه بین المللی امام خمینی (ره) - قزوین - دانشکده علوم پایه 1390

چکیده : * در یک واکنش تک ظرفی و با استفاده از واکنش آلدهید های آروماتیک و 3- متیل 1- فنیل پیرازولین-5- ان با نسبت مولی 1:1، ساختارهای هتروسیکل پیرازول سنتز شد. از مزایای آن، انجام واکنش در دمای اتاق، عدم نیاز به کاتالیزور، بازده بالای واکنش، استفاده از آب بعنوان حلال سبز و بی خطر به جای حلال های آلی وسمی می باشد . * توانستیم با استفاده از ملدرام اسید ومشتقات 2- هیدروکسی بنزآلدهید، ترکی...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه ارومیه - دانشکده علوم 1391

nanotechnology is a general term which is related with field of all advanced science term that generally predicates with all modern technologies which consider nanoscales. improvement in the quality of products by adding some nanoparticles and study of their behavior in the presence of these nanoparticles have been obtained in many researches. on the other hand numerous demands for sowing ...

Journal: :international journal of environmental research 2011
d.k. kim k.s. jeong r.i.b. mckay t.s. chon g.j. joo

in the regulated nakdong river, algal proliferations are annually observed in some seasons, with cyanobacteria (microcystis aeruginosa) appearing in summer and diatom blooms (stephanodiscus hantzschii) in winter. this study aims to develop two ecological models forecasting future chlorophyll a at two time-steps (one-week and one-year forecasts), using recurrent neural networks tuned by genetic...

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