نتایج جستجو برای: zidasht catchment

تعداد نتایج: 12250  

حسن زاده نفوتی, محمد , خواجه بافقی, حبیب ا... ,

Today, one of the major problems of flood control projects is watershed prioritizing for resource allocation and structural and non-structural practices. Due to the lack of hydrometric stations in many watersheds, is difficult determining the participation of sub catchments to create flood. So study the affective factors in watersheds through models such as multi-criteria decision analyzing sys...

2004
Brian L. McGlynn Jeffrey J. McDonnell Jan Seibert Carol Kendall

[1] The effects of catchment size and landscape organization on runoff generation are poorly understood. Little research has integrated hillslope and riparian runoff investigation across catchments of different sizes to decipher first-order controls on runoff generation. We investigated the role of catchment sizes on riparian and hillslope dynamics based on hydrometric and tracer data observed ...

Journal: :Journal of environmental quality 2017
R W McDowell N Cox T H Snelder

Catchment contaminant loads vary with stream order as catchment characteristics influence inputs and in-stream processing. However, the relative influence and policy significance of these characteristics across a number of contaminants and at a national scale is unclear. We modeled the significance of catchment characteristics (e.g., climate, topography, geology, land cover), as captured by a n...

2014
D. E. Walling P. Du P. Porto Y. Zhang

The application of fallout radionuclides in soil erosion and sedimentation investigations has provided a valuable tool for improving the understanding of erosion and sediment transfer processes. However, most studies using fallout radionuclides have focussed on small areas. Increasing acceptance of the important role of fine sediment in degrading aquatic habitats and in the transfer and fat...

Journal: :Journal of environmental quality 2007
Marcel van der Perk Philip N Owens Lynda K Deeks Barry G Rawlins Philip M Haygarth Keith J Beven

Many models of phosphorus (P) transfer at the catchment scale rely on input from generic databases including, amongst others, soil and land use maps. Spatially detailed geochemical data sets have the potential to improve the accuracy of the input parameters of catchment-scale nutrient transfer models. Furthermore, they enable the assessment of the utility of available, generic spatial data sets...

2014
Anja du Plessis Fethi Ahmed Ataur Rahman

The integrity of the Blesbok Spruit catchment has been significantly compromised over the past decades, mainly due to the discharge of mining effluent and sewage. This research investigated the hydrological responses, in terms of water quality, in the event of land cover change within the catchment to make predictions on the future sustainability of the region’s water resources with the applica...

2006
JONATHAN A. O’DONNELL

1. Riparian zones function as important ecotones that reduce nitrate concentration in groundwater and inputs into streams. In the boreal forest of interior Alaska, permafrost confines subsurface flow through the riparian zone to shallow organic horizons, where plant uptake of nitrate and denitrification are typically high. 2. In this study, riparian zone nitrogen retention was examined in a hig...

2005
I. D. Brewer

The character and distribution of cooling ages in modern river sediment provide useful constraints on rates and patterns of uplift and erosion within actively deforming mountain ranges. Such sediment effectively samples all locations within the catchment area, irrespective of remoteness. We evaluate how successfully detrital cooling ages may be used to constrain hinterland erosion rates by exam...

2012
Matthew R McGrail

BACKGROUND The two step floating catchment area (2SFCA) method has emerged in the last decade as a key measure of spatial accessibility, particularly in its application to primary health care access. Many recent 'improvements' to the original 2SFCA method have been developed, which generally either account for distance-decay within a catchment or enable the usage of variable catchment sizes. Th...

2017
Sarah H Luke Holly Barclay Kawi Bidin Vun Khen Chey Robert M Ewers William A Foster Anand Nainar Marion Pfeifer Glen Reynolds Edgar C Turner Rory P D Walsh David C Aldridge

Freshwaters provide valuable habitat and important ecosystem services but are threatened worldwide by habitat loss and degradation. In Southeast Asia, rainforest streams are particularly threatened by logging and conversion to oil palm, but we lack information on the impacts of this on freshwater environmental conditions, and the relative importance of catchment versus riparian-scale disturbanc...

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