نتایج جستجو برای: alluvial

تعداد نتایج: 3577  

2017
Andrew Brooks John Spencer Jon Knight

Alluvial gully erosion is a likely key sediment source into many large rivers in tropical Australia. This type of gullying differs fundamentally to the generally accepted gully model from Southern Australia, in that it is found exclusively within alluvium and can propagate entirely as a result of basal sapping. The process is found to varying degrees within alluvial river types along most Gulf ...

Journal: :Archives of environmental contamination and toxicology 2004
Bart Vandecasteele Paul Quataert Bruno De Vos Filip M G Tack

The concept of an integrated multifunctional river management is gaining importance. For major rivers, restoring the contact between rivers and alluvial plains is an important goal, as riparian areas have a specific role for several riverine processes. However, former and current human activities are an obstruction or a limitation for river restoration. We studied the influence of former dredgi...

2007
Gokmen Tayfur Vijay P. Singh

[1] Transient bed profiles in alluvial channels are generally modeled using diffusion (or dynamic) waves and assuming equilibrium between detachment and deposition rates. Equilibrium sediment transport can be considerably affected by an excess (or deficiency) of sediment supply due to mostly flows during flash floods or floods resulting from dam break or dike failure. In such situations the sed...

2006
J. B. Norton

Combined effects of brush encroachment and channel entrenchment in the Southwestern United States threaten ecological, hydrological, and agricultural functions of ephemeral streams and associated alluvial surfaces. Restoration is difficult because entrenchment is widespread, and highly variable flow magnitudes defy standardized structural approaches. Methods developed by the Zuni Indians during...

2012
S. Bernal F. Sabater

To gain understanding on how alluvial zones modify water and nutrient export from semiarid catchments, we compared monthly discharge as well as stream chloride, carbon, and nitrogen dynamics between a hillslope catchment and a valley-bottom catchment with a well-developed alluvium. Stream water and solute fluxes from the hillslope and valley-bottom catchments showed contrasting patterns between...

2011
Andrea Taramelli A. Taramelli

In Geomorphology the landforms delineation and delimitation are based on traditional techniques which is usually achieved by two different approaches: semantic and geometric. The semantic approach involves interpreting aerial photographs as well as using field knowledge to map the possible landforms extent. The geometric approach involves inferring the probability of extension on related proper...

Journal: :FEMS microbiology ecology 2014
Susanne Schreiter Guo-Chun Ding Rita Grosch Siegfried Kropf Kai Antweiler Kornelia Smalla

Bacterial biocontrol strains used as an alternative to chemical fungicides may influence bacterial communities in the rhizosphere and effects might differ depending on the soil type. Here we present baseline data on the effects of Pseudomonas jessenii RU47 on the bacterial community composition in the rhizosphere of lettuce grown in diluvial sand, alluvial loam and loess loam at the same field ...

2005
J. A. Saunders Richard T. Wilkin Mostafa Fayek Nic E. Korte

[1] Linked tectonic, geochemical, and biologic processes lead to natural arsenic contamination of groundwater in Holocene alluvial aquifers, which are the main threat to human health around the world. These groundwaters are commonly found a long distance from their ultimate source of arsenic, where chemical weathering of As-bearing minerals occurs. We propose a ‘‘GBH-As’’ model that ties togeth...

2016

Facies reconstructions are used in hydrogeology to improve the interpretation of aquifer permeability.. In the absence of sufficient data to define the heterogeneity due to geological processes, uncertainties in the distribution of aquifer hydrofacies and characteristics may appear. Geometric and geostatistical methods are used to understand and model aquifer hydrofacies distribution, providing...

Journal: :Environmental pollution 2011
Huaming Guo Bo Zhang Yuan Li Zsolt Berner Xiaohui Tang Stefan Norra Doris Stüben

Little is known about the importance of drainage/irrigation channels and biogeochemical processes in arsenic distribution of shallow groundwaters from the Hetao basin. This investigation shows that although As concentrations are primarily dependent on reducing conditions, evaporation increases As concentration in the centre of palaeo-lake sedimentation. Near drainage channels, groundwater As co...

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