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Digital elevation analysis for distributed hydrological modelling: reducing scale dependence in effective hydraulic conductivity values.

Research output: Contribution to journalJournal article

Published

Journal publication date1997
JournalWater Resources Research
Journal number9
Volume33
Number of pages5
Pages2097-2101
Original languageEnglish

Abstract

The recent widespread availability of digital terrain data has made automatic procedures for topographic analyses popular. Previous studies have shown that hydrological models and their effective parameter values are dependent on the resolution of the elevation grid. This paper examines the analysis of raster elevation data within the topography-based model, TOPMODEL, framework. It is demonstrated that the algorithm used in processing channel pixels in calculating the topographic index k = ln(a/tanβ) can have a dramatic effect on the sensitivity of effective parameter values to the grid size. Suggestions are made for calculating the topographic index of channel pixels, consistent with the TOPMODEL assumptions, that strongly decrease the sensitivity of the calibrated effective hydraulic conductivity values to grid size.