نتایج جستجو برای: surface runoff and peak discharges rates increased

تعداد نتایج: 16996668  

1999
David L. Correll Thomas E. Jordan Donald E. Weller

We studied storm discharges of nitrate and dissolved and particulate forms of ammonium, organic N, phosphate, and organic P from four adjacent small watersheds of differing land use on the Atlantic Coastal Plain in Maryland. We used V-notch weirs and automated storm samplers to measure discharges and collect samples at flow intervals during 76 storms. The watershed aquifers are perched on an im...

Journal: :پژوهش های جغرافیای طبیعی 0
سمیه خالقی استادیار گروه جغرافیای طبیعی، دانشکدة علوم زمین، دانشگاه شهید بهشتی لیلا ملکانی استادیار گروه عمران، دانشکدة فنی - مهندسی مرند، دانشگاه تبریز

introduction flood is an inevitable natural phenomenon occurring from time to time in all rivers and natural drainage systems, which not only damages the lives, natural resources and environment, but also causes the loss of economy and health. so estimation and prediction flood hazard is very important spatially in the watersheds without measurement station. there are many models in the water a...

2012
A. Majidi K. Shahedi

Estimation of surface runoff in a watershed based on the rate of received precipitation and quantifying discharge at outlet is important in hydrologic studies. In this study, HEC-HMS hydrological model version 3.4 was used to simulate rainfall-runoff process in Abnama watershed located in south of Iran. To compute infiltration, rainfall excess conversion to runoff and flow routing, methods like...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه صنعتی اصفهان - دانشکده شیمی 1391

in this project, 4,4?-methylenebis(3-chloro-2,6-diethyl trimellitimidobenzene) as a diacid, was prepared by the reaction of trimellitic anhydride (tma) with 4,4?-methylenebis(3-chloro-2,6-diethylaniline) (mcdea). the novel poly(amide-imide) (pai) was synthesized from the reaction of 4,4?-methylenebis(3-chloro-2,6-diethyl trimellitimidobenzene) as a diacid with mcdea under green condition using ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه رازی - دانشکده علوم 1389

fluorescence chemical sensors for the highly sensitive and selective determination of pb2+ , hg2+, co2+ and fe3+ ions in aqueous solutions are described. the ion sensing system was prepared by incorporating lipophilic ligand (l) as a neutral ion-selective fluoroionophore in the plasticized pvc membrane containing sodium tetraphenylborate or potasium tetrakis (p-chlorophenyl) borate as a liphoph...

2016
John E. Gilley Jason R. Vogel Roger A. Eigenberg David B. Marx Brian L. Woodbury

Beef cattle feedlots contain unconsolidated surface materials (loose manure pack) that accumulate during a feeding cycle. The effects of varying amounts of unconsolidated surface materials on runoff nutrient losses are not well understood. The objectives of this study were to (1) compare runoff nutrient losses from feedlot surfaces containing varying amounts of unconsolidated surface materials,...

پایان نامه :وزارت بهداشت، درمان و آموزش پزشکی - دانشگاه علوم پزشکی و خدمات بهداشتی درمانی مشهد - دانشکده دندانپزشکی 1390

objective: the objective of this study was to investigate the invitro fluoride release of four new self-adhesive resin cements; set (sdi, australia), breeze (pentron, usa), embrace wetbond (pulpdent, usa), g-cem (gc, japan) and to assess the bonding performance of these self-adhesive resin cements for bonding of orthodontic brackets. materials and methods: for fluoride release experiment, six ...

Journal: :اکو هیدرولوژی 0
مسعود گودرزی استادیار، پژوهشکدۀ حفاظت خاک و آبخیزداری، تهران برومند صلاحی دانشیار، دانشکدۀ علوم انسانی، دانشگاه محقق اردبیلی، اردبیل سید اسعد حسینی دانشجوی دکتری، دانشکدۀ علوم انسانی، دانشگاه محقق اردبیلی، اردبیل

climate change is one of the most important problems in the present century. so assessing and prediction of future changes is important on water resources and so important for economics and socio-economic consequences. the purpose of this research is assessing the effects of climate change on surface runoff volumes under the scenarios: a1b, a2 and b1 using hadcm3 general circulation model and i...

Journal: :Remote Sensing 2010
Carmelo Conesa-Garcia Vicente Caselles-Miralles Juan M. Sanchez Tomas Rafael Garcia-Lorenzo

This paper shows the combined use of remotely sensed data and hydraulic geometry methods as an alternative to rainfall-runoff models. Hydraulic geometric data and boolean images of water sheets obtained from satellite images after storm events were integrated in a Geographical Information System. Channel cross-sections were extracted from a high resolution Digital Terrain Model (DTM) and superi...

2003
Joseph Holden Tim P. Burt

[1] Blanket peat catchments exhibit flashy regimes, but little is known about the exact nature of runoff production processes within these catchments. Catchment, hillslope, and plot-scale monitoring results are presented from the blanket peats of the northern Pennines, United Kingdom. Catchment efficiency for three study catchments with areas of 11.4 km, 0.83 km, and 0.44 km were 72%, 77%, and ...

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