The concept of effective length in hillslopes: assessing the influence of climate and topography on the contributing areas of catchments
Article first published online: 21 NOV 2002
Copyright © 2002 John Wiley & Sons, Ltd.
Volume 17, Issue 1, pages 131–151, January 2003
How to Cite
Aryal, S. K., Mein, R. G. and O'Loughlin, E. M. (2003), The concept of effective length in hillslopes: assessing the influence of climate and topography on the contributing areas of catchments. Hydrol. Process., 17: 131–151. doi: 10.1002/hyp.1137
- Issue published online: 19 DEC 2002
- Article first published online: 21 NOV 2002
- Manuscript Accepted: 25 MAR 2002
- Manuscript Received: 31 AUG 2001
- effective length;
- dynamic contributing area;
- hillslope hydrology;
- hillslope shapes
This paper introduces a concept of ‘effective length’ in hillslopes to define the effective area influencing the runoff-producing saturated zones of a hillslope or catchment. This effective area of a catchment usually is less than that given by its physical boundaries, particularly in regions where the total potential evaporation exceeds total rainfall on an annual basis. In this paper, expressions for effective lengths in hillslopes with different scale, shape and soil properties are derived for given climatic conditions. The influence of these variables on effective length is investigated. It is shown that, for a given rainfall frequency and soil parameters, the effective length changes with the planform geometry and profile shape of a hillslope; it is also a function of the ratio of available travel opportunity time to the hillslope's scale response time. The application of the concept to three natural catchments, subdivided into a number of simple hillslopes, is described. It is shown that, for these three test catchments and over 24 years of record, rarely would the entire catchment areas contribute to flow at the respective outlets. The implications of the concept of effective length for several land-use practices, such as clearing for forest for greater water yield, and planting trees for salinity control, are discussed. Copyright © 2002 John Wiley & Sons, Ltd.