Centimetre-scale digital representations of terrain and impacts on depression storage and runoff

Auteur(s) et Affiliation(s)



Description :
The microscale topography of a 20x10 m hillslope in a burned portion of Kootenay National Park, British Columbia was determined through laser scanning at a sub-centimetre scale. Digital terrain models (DTM) were developed for this hillslope at the 0.75 cm, 10 cm, 25 cm, 50 cm, 75 cm and 1 m scales. Random Roughness, Tortuosity and Mean Upslope Depression were computed for bare and vegetated surfaces created at each resolution to determine mean depression storage as a function of resolution. Results for these various roughness parameters and associated depression storage values are not found to change appreciably between the vegetated and bare surface DTMs, and moreover do not change notably with increasing grid cell resolution. Depression storage was also computed using a GIS-based method. The values of depression storage for the various scales of DTM are demonstrated to have significant influences on overland flow generation. The scale of the DTM affects the changes over time between the proportion of water going into depression storage and that contributing to overland flow. When overland flow develops from a rising groundwater table in a simulation exercise, water depths are initially lower than the primary roughness elements on the land surface and water is relatively disconnected. As water depths increase, more integrated connections form.


Type de document :
Article de périodique

Source :
Catena (Giessen), issn : 0341-8162, 2008, vol. 75, n°. 2, p. 223-233, nombre de pages : 11, Références bibliographiques : 27 ref.

Date :
2008

Editeur :
Pays édition : Allemagne, Cremlingen-Destedt, Catena