Hillslope Runoff Through Grids of Patchy Vegetation: Predictions Using Modified Percolation Theory
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Authors
Kurc, Shirley
Issue Date
1997
Type
Thesis
Language
en_US
Keywords
Alternative Title
Abstract
In pinon-juniper woodland sites, rapid transitions from low to high rates of
hillslope runoff and erosion rates appear to occur with changes in ground cover.
We use modified percolation equations, which have been used to predict rapid
transitions between two states, to account for slope and to investigate scale-dependent
relations for hillslope runoff. Hillslope runoff for a grid of cells is
defined to be the number of runoff generating cells that actually contribute to the
runoff at the bottom of the grid. We investigate how spatial pattern of runoff
generating cells and grid scale effects hillslope runoff. We find that hillslope
runoff increases non-linearly with percent of bare cells, crossing a threshold at
intermediate values. This is similar to the behavior in general percolation theory
and is important because it describes the transition between low and high levels
of erosion. We also find that hillslope runoff is dependent on spatial pattern;
spatial patterns are important because vegetation is aggregated in different
ways at different sites. We also show that hillslope runoff is dependent on grid
scale; grid scale is important because hillslopes vary in size. In general, rapid
transitions are of concern because they effect the redistribution of contaminants
and can deteriorate landfill covers. This preliminary study provides insight into a
technique that can be useful in describing the dynamics of a transition between
a low level and a high level of erosion.
Description
v, 30 p.
Citation
Publisher
Kalamazoo College
License
U.S. copyright laws protect this material. Commercial use or distribution of this material is not permitted without prior written permission of the copyright holder.