Premium
Field Experiments on Erosion by Overland Flow and Their Implication for a Digital Terrain Model of Channel Initiation
Author(s) -
Prosser Ian P.,
Dietrich William E.
Publication year - 1995
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/95wr02218
Subject(s) - flume , geology , critical resolved shear stress , shear stress , geotechnical engineering , sediment transport , geomorphology , terrain , hydraulic roughness , surface runoff , digital elevation model , flow (mathematics) , soil science , hydrology (agriculture) , sediment , surface finish , geometry , mechanics , mathematics , engineering , shear rate , geography , remote sensing , ecology , biology , quantum mechanics , viscosity , mechanical engineering , physics , cartography
Dietrich et al. (1992, 1993) proposed a digital terrain model for predicting the location of channel heads on the basis of the assumption that they occur where saturation overland flow exerts a boundary shear stress in excess of a critical value. Flume experiments were conducted in the modeled field site to evaluate the threshold hypothesis and to constrain critical shear stress and flow resistance parameters. Under complete grass cover, microtopography and grass stems were found to prevent significant sediment transport at all but the highest flows. When the grass stems were cut close to the ground, flow resistance and critical shear stress for significant sediment transport were reduced by up to an order of magnitude, but the remaining dense root mat prevented deep scour. These field experiments support the threshold assumption and the model estimations of the critical shear stress if local topographic convergence of flow is taken into account. The experiments also support the interpretation that significant degradation of vegetation cover is required for channel incision.