نتایج جستجو برای: catchments

تعداد نتایج: 4452  

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2017
Mark A Torres Nils Moosdorf Jens Hartmann Jess F Adkins A Joshua West

Connections between glaciation, chemical weathering, and the global carbon cycle could steer the evolution of global climate over geologic time, but even the directionality of feedbacks in this system remain to be resolved. Here, we assemble a compilation of hydrochemical data from glacierized catchments, use this data to evaluate the dominant chemical reactions associated with glacial weatheri...

Journal: :Remote Sensing 2014
Webster Gumindoga T. H. M. Rientjes Munyaradzi Davis Shekede Donald Tendayi Rwasoka Innocent Nhapi Alemseged Tamiru Haile

By increased rural-urban migration in many African countries, the assessment of changes in catchment hydrologic responses due to urbanization is critical for water resource planning and management. This paper assesses hydrological impacts of urbanization on two medium-sized Zimbabwean catchments (Mukuvisi and Marimba) for which changes in land cover by urbanization were determined through Lands...

2012
Eung Seok Kim Hyun Il Choi

An increase in the occurrence of sudden local flooding of great volume and short duration has caused significant danger and loss of life and property in Korea as well as many other parts of the World. Since such floods usually accompanied by rapid runoff and debris flow rise quite quickly with little or no advance warning to prevent flood damage, this study presents a new flash flood indexing m...

2004
Fengjing Liu Mark W. Williams Nel Caine

[1] Source waters and flow paths of streamflow draining high-elevation catchments of the Colorado Rocky Mountains were determined using isotopic and geochemical tracers during the 1996 snowmelt runoff season at two subcatchments of the Green Lakes Valley, Colorado Front Range. A two-component hydrograph separation using dO indicates that new water dominated (82 ± 6%) streamflow at the 8-ha Mart...

2006
Kevin J. McGuire Jeffrey J. McDonnell

Transit time is a fundamental catchment descriptor that reveals information about storage, flow pathways and source of water in a single characteristic. Given the importance of transit time, little guidance exists for the application of transit time modeling in complex catchment systems. This paper presents an evaluation and review of the transit time literature in the context of catchments and...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2017
Lisa A Schulte Jarad Niemi Matthew J Helmers Matt Liebman J Gordon Arbuckle David E James Randall K Kolka Matthew E O'Neal Mark D Tomer John C Tyndall Heidi Asbjornsen Pauline Drobney Jeri Neal Gary Van Ryswyk Chris Witte

Loss of biodiversity and degradation of ecosystem services from agricultural lands remain important challenges in the United States despite decades of spending on natural resource management. To date, conservation investment has emphasized engineering practices or vegetative strategies centered on monocultural plantings of nonnative plants, largely excluding native species from cropland. In a c...

2017
Rodolfo L B Nóbrega Alphonce C Guzha Gilmar N Torres Kristof Kovacs Gabriele Lamparter Ricardo S S Amorim Eduardo Couto Gerhard Gerold

Understanding the impacts of land-use change on landscape-hydrological dynamics is one of the main challenges in the Northern Brazilian Cerrado biome, where the Amazon agricultural frontier is located. Motivated by the gap in literature assessing these impacts, we characterized the soil hydro-physical properties and quantified surface water fluxes from catchments under contrasting land-use in t...

Journal: :International Journal of Health Geographics 2006
Nadine Schuurman Robert S Fiedler Stefan CW Grzybowski Darrin Grund

BACKGROUND Cost containment typically involves rationalizing healthcare service delivery through centralization of services to achieve economies of scale. Hospitals are frequently the chosen site of cost containment and rationalization especially in rural areas. Socio-demographic and geographic characteristics make hospital service allocation more difficult in rural and remote regions. This res...

Journal: :Environmental Modelling and Software 2002
Rebecca A. Kelly Anthony J. Jakeman M. Calfas S. Linforth B. Baginska I. Lawrence

Information on water quality, in particular on sediment, phosphorus and nitrogen exports from catchments, is required by catchment managers and other stakeholder groups to determine appropriate management options for water quality issues. However intensive spatial and temporal data on concentrations or loads of these nutrients is relatively scarce. Given this constraint, nutrient export models ...

2005
Joseph Holden

[1] Soil pipes were surveyed in 160 British blanket peat catchments using consistent application of ground-penetrating radar. Soil pipes were found in all catchments. The mean frequency of piping was 69 per kilometer of surveyed transect. Land management (moorland gripping) appears to exert the most important control on hillslope pipe frequency in blanket peats. Management practice in peatlands...

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