نتایج جستجو برای: floodplains

تعداد نتایج: 1171  

Journal: :Proceedings of the National Academy of Sciences 2017

2018
B. Naik K. K. Khatua N. G. Wright A. Sleigh

Momentum transfer between the main channel and the side flood plains tends to increase the floodplain shear whereas the main channel shear decreases. The increase and decrease in shear are greatly influenced when a compound channel is with non-prismatic flood plains. In converging compound channels water flow on the floodplain crosses over water flow in the main channel, resulting in increased ...

2004
J. Järvelä

Flow resistance due to vegetation may greatly affect the conveyance of a channel, and thus evaluating the resistance is a critical task in river engineering and restoration. Therefore, flow resistance of natural willows and sedges was studied in a laboratory flume. The aim was to investigate, how type, density and combination of vegetation, flow depth and velocity influence vegetal drag or fric...

2012
CHARLES A. NITTROUER

Floodplain sedimentation removes particles from fluvial transport and constructs stratigraphic records of flooding, biogeochemical sequestration and other aspects of the environmental history of river basins—insight that is enhanced by accurate geochronology. The natural fallout radionuclide 210Pb, often employed to date lacustrine and marine sediments, has previously been used to determine flo...

2017
Daniel H. Mann Dorothy M. Peteet Richard E. Reanier Michael L. Kunz

Many of the physical and biological processes that characterize arctic ecosystems are unique to high latitudes, and their sensitivities to climate change are poorly understood. Stratigraphic records of land–surface processes and vegetation change in the Arctic Foothills of northern Alaska reveal how tundra landscapes responded to climatic changes between 13,000 and 8000 C yr BP. Peat deposition...

Journal: :Remote Sensing 2012
Jochem Verrelst Erika Romijn Lammert Kooistra

River floodplains in the Netherlands serve as water storage areas, while they also have the function of nature rehabilitation areas. Floodplain vegetation is therefore subject to natural processes of vegetation succession. At the same time, vegetation encroachment obstructs the water flow into the floodplains and increases the flood risk for the hinterland. Spaceborne pointable imaging spectros...

2017
Jacob V E Katz Carson Jeffres J Louise Conrad Ted R Sommer Joshua Martinez Steve Brumbaugh Nicholas Corline Peter B Moyle

When inundated by floodwaters, river floodplains provide critical habitat for many species of fish and wildlife, but many river valleys have been extensively leveed and floodplain wetlands drained for flood control and agriculture. In the Central Valley of California, USA, where less than 5% of floodplain wetland habitats remain, a critical conservation question is how can farmland occupying th...

Journal: :Bulletin of entomological research 2010
T Z Persson Vinnersten J O Lundström M L Schäfer E Petersson J Landin

In temporary wetlands in the River Dalälven floodplains, recurrent but irregular floods induce massive hatching of the flood-water mosquito Aedes sticticus, which causes enormous nuisance. Flood-water mosquito control using the biological larvicide Bacillus thuringiensis var. israelensis (Bti) was commenced in parts of the floodplains during 2002, and here we report the first six years of full-...

2017
Tongtiegang Zhao Quanxi Shao Yongyong Zhang

The flood-mediated connectivity between river channels and floodplains plays a fundamental role in flood hazard mapping and exerts profound ecological effects. The classic nearest neighbor search (NNS) fails to derive this connectivity because of spatial heterogeneity and continuity. We develop two novel data-driven connectivity-deriving approaches, namely, progressive nearest neighbor search (...

2005
Douglas Alsdorf Thomas Dunne John Melack Laurence Smith Laura Hess

[1] We present a continuity-based approach for calculating flow delivered to a main channel from an adjacent floodplain and use the values in a linear diffusion model to generalize fluxes across a floodplain. Using interferometric synthetic aperture radar (SAR) measurements of floodplain water level changes and the continuity equation, we demonstrate that flow rates are not the same throughout ...

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