نتایج جستجو برای: watersheds ie

تعداد نتایج: 25913  

2005
James D. Wickham Kurt H. Riitters Robert V. O'Neill Kenneth H. Reckhow Timothy G. Wade Bruce Jones

A survey of numerous field studies shows that nitrogen and phosphorous export coefficients are significantly different across forest, agriculture, and urban land-cover types. We used simulations to estimate the land-cover composition at which there was a significant risk of nutrient loads representative of watersheds without forest cover. The results suggest that at between 20 percent and 30 pe...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2015
Marc P Verhougstraete Sherry L Martin Anthony D Kendall David W Hyndman Joan B Rose

Linking fecal indicator bacteria concentrations in large mixed-use watersheds back to diffuse human sources, such as septic systems, has met limited success. In this study, 64 rivers that drain 84% of Michigan's Lower Peninsula were sampled under baseflow conditions for Escherichia coli, Bacteroides thetaiotaomicron (a human source-tracking marker), landscape characteristics, and geochemical an...

2002
W. Keller

........................................................................................................................................................ 195 Introduction .................................................................................................................................................. 195 Geological Control of Sudbury’s Lakes .........................................

Journal: :Gaceta sanitaria 2012
Sara Esteban Yolanda Valcárcel Myriam Catalá Miguel González Castromil

OBJECTIVE To monitor the presence of pharmaceutical residues of 14 psychoactive drugs belonging to three therapeutic groups in the watersheds of Galicia (Spain). METHOD Five sewage treatment plants were selected in the main cities of Galicia. Thirteen psychoactive pharmaceutical compounds and one metabolite were chosen. In addition, tap water samples were taken from public places and private ...

2006
Eran Hood Michael N. Gooseff Sherri L. Johnson

[1] The hydrologic and biogeochemical responses of forested watersheds to inputs of rainfall and snowmelt can be an indicator of internal watershed function. In this study, we assess how the quantity and quality, both chemical and spectroscopic, of stream water DOC changes in response to a 6-day storm event during the wet season of 2003 in three small (<1 km) basins in the H. J. Andrews Experim...

2010
Megan P. Burke Terri S. Hogue Marcia Ferreira Carolina B. Mendez Bridget Navarro Sonya Lopez Jennifer A. Jay

Mercury (Hg) stored in vegetation and soils is known to be released to the atmosphere during wildfires, increasing atmospheric stores and altering terrestrial budgets. Increased erosion and transport of sediments is well-documented in burned watersheds, both immediately post-fire and as the watershed recovers; however, understanding post-fire mobilization of soil Hg within burned watersheds rem...

Journal: :Applied and environmental microbiology 2003
Bruce A Wiggins Philip W Cash Wes S Creamer Scott E Dart Preston P Garcia Todd M Gerecke Jennifer Han Brian L Henry Kylie B Hoover Erika L Johnson K C Jones Jacquie G McCarthy Justin A McDonough Sarah A Mercer Michael J Noto Haewon Park Matthew S Phillips Stephanie M Purner Brian M Smith Erin N Stevens Amy K Varner

The use of antibiotic resistance analysis (ARA) for microbial source tracking requires the generation of a library of isolates collected from known sources in the watershed. The size and composition of the library are critical in determining if it represents the diversity of patterns found in the watershed. This study was performed to determine the size that an ARA library needs to be to be rep...

2005
A. L. Horn

Hydrologic models of watersheds often represent complex systems which are difficult to understand regarding to their structure and dynamics. Virtual watersheds, i.e. watersheds which exist only in the virtual reality of a computer system, are an approach to simplify access to this real-world complexity. In this study we present the virtual watershed KIELSHED-1, a 117 km2 v-shaped valley with gr...

2003
Matei Mancas Bernard Gosselin

This paper introduces a simple knowledge model on CT (Computed Tomography) images which provides high level information. A novel method called iterative watersheds is then used in order to segment the tumors. Moreover, a fully automatic tumor segmentation method was tested by using image registration. Some preliminary results are very encouraging and give us hope to obtain an interesting tool f...

2016
Muhammad Ajmal Taj Ali Khan Tae-Woong Kim Kwok-wing Chau

A major structural inconsistency of the traditional curve number (CN) model is its dependence on an unstable fixed initial abstraction, which normally results in sudden jumps in runoff estimation. Likewise, the lack of pre-storm soil moisture accounting (PSMA) procedure is another inherent limitation of the model. To circumvent those problems, we used a variable initial abstraction after ensemb...

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