Knickpoint recession rate and catchment area: the case of uplifted rivers in Eastern Scotland

Bishop, P., Hoey, T.B., Jansen, J.D. and Artza, I.L. (2005) Knickpoint recession rate and catchment area: the case of uplifted rivers in Eastern Scotland. Earth Surface Processes and Landforms, 30(6), pp. 767-778. (doi: 10.1002/esp.1191)

Abstract

Knickpoint behaviour is a key to understanding both the landscape responses to a base-level fall and the corresponding sediment fluxes from rejuvenated catchments, and must be accommodated in numerical models of large-scale landscape evolution. Knickpoint recession in streams draining to glacio-isostatically uplifted shorelines in eastern Scotland is used to assess whether knickpoint recession is a function of discharge (here represented by its surrogate, catchment area). Knickpoints are identified using DS plots (log slope versus log downstream distance). A statistically significant power relationship is found between distance of headward recession and catchment area. Such knickpoint recession data may be used to determine the values of m and n in the stream power law, E = KAmSn. The data have too many uncertainties, however, to judge definitively whether they are consistent with m = n = 1 (bedrock erosion is proportional to stream power and KPs should be maintained and propagate headwards) or m = 0·3, n = 0·7 (bedrock incision is proportional to shear stress and KPs do not propagate but degrade in place by rotation or replacement). Nonetheless, the E Scotland m and n values point to the dominance of catchment area (discharge) in determining knickpoint retreat rates and are therefore more consistent with the stream power law formulation in which bedrock erosion is proportional to stream power.

• Item Type: Articles
• Keywords: knickpoint, stream power law, bedrock river, glacio-isostatic rebound, Eastern Scotland
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Jansen, Dr John and Bishop, Professor Paul
• Authors: Bishop, P., Hoey, T.B., Jansen, J.D., and Artza, I.L.
• Subjects: G Geography. Anthropology. Recreation > GB Physical geography
• College/School: College of Science and Engineering > School of Geographical and Earth Sciences
• Journal Name: Earth Surface Processes and Landforms
• Publisher: John Wiley and Sons
• ISSN: 0197-9337
• ISSN (Online): 1096-9837
• Published Online: 17 May 2005
• Copyright Holders: Copyright © 2005 Wiley and Sons.
• First Published: First published in Earth Surface Processes and Landforms 30(6):767-778
• Publisher Policy: Reproduced in accordance with the copyright policy of the publisher