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Multi-scale permeability estimation in a tropical catchment.

Chappell, Nick A. and Franks, Stewart W. and Larenus, Jonny (1998) Multi-scale permeability estimation in a tropical catchment. Hydrological Processes, 12 (9). pp. 1507-1523. ISSN 0885-6087

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Abstract

Physically based and spatially distributed modelling of catchment hydrology involves the estimation of block or whole-hillslope permeabilities. Invariably these estimates are derived by calibration against rainfall-runoff response. Rarely are these estimates rigorously compared with parameter measurements made at the small scale. This study uses a parametrically simple model, TOPMODEL, and an uncertainty framework to derive permeability at the catchment scale. The utility of expert knowledge of the internal catchment dynamics (i.e. extent of saturated area) in constraining parameter uncertainty is demonstrated. Model-derived estimates are then compared with core-based measurements of permeability appropriately up-scaled. The observed differences between the permeability estimates derived by the two methods might be attributed to the role of intermediate scale features (natural soil pipes). An alternative method of determining block permeabilities at the intermediate or hillslope scale is described. This method uses pulse-wave tests and explicitly incorporates the resultant effects of phenomena such as soil piping and kinematic wave migration. The study aims to highlight issues associated with parameterizing or validating distributed models, rather than to provide a definitive solution. The fact that the permeability distribution within the Borneo study catchment is comparatively simple, assists the comparisons. The field data were collected in terrain covered by equatorial rainforest. Combined field measurement and modelling programmes are rare within such environments.

Item Type: Article
Journal or Publication Title: Hydrological Processes
Uncontrolled Keywords: parameter uncertainty • permeability ; soil piping • TOPMODEL • upscaling
Subjects: G Geography. Anthropology. Recreation > GE Environmental Sciences
Departments: Faculty of Science and Technology > Lancaster Environment Centre
Faculty of Arts & Social Sciences > Politics & International Relations (Merged into PPR 2010-08-01)
ID Code: 21807
Deposited By: ep_ss_importer
Deposited On: 09 Feb 2009 10:09
Refereed?: Yes
Published?: Published
Last Modified: 26 Jul 2012 15:52
Identification Number:
URI: http://eprints.lancs.ac.uk/id/eprint/21807

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