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Generation of storm runoff and the role of animals in a small upland headwater stream
Author(s) -
Meijles Erik W.,
Dowd John F.,
Williams Andrew G.,
Heppell Catherine M.
Publication year - 2015
Publication title -
ecohydrology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.982
H-Index - 54
eISSN - 1936-0592
pISSN - 1936-0584
DOI - 10.1002/eco.1584
Subject(s) - surface runoff , environmental science , hydrology (agriculture) , storm , runoff curve number , drainage basin , vegetation (pathology) , flooding (psychology) , streamflow , geology , ecology , geography , medicine , psychology , oceanography , geotechnical engineering , cartography , pathology , psychotherapist , biology
This paper illustrates the hillslope storm runoff mechanisms and the effects of livestock in upland areas. The research site was a small upland catchment area on Dartmoor (Southwest England). It was shown that overland flow on the tracks and paths created by animals in the area responded very rapidly to rainfall, in the same order of magnitude as stream runoff. Livestock stocking densities were significantly different in different vegetation compositions. The topsoil bulk density values, moisture content and spatial track densities were significantly higher in areas associated with higher stocking rates. These areas reach a wetness threshold at an earlier state than surrounding, drier areas. When isolated, the wetter areas start discharging water only locally into downslope drier areas, but are not contributing to storm runoff in the stream. In areas with a high density of animal tracks, water is being discharged onto the track directly. The tracks comprised an ephemeral hydrological network contributing storm runoff to the stream quickly after rainfall. They transmit water rapidly downhill, short‐circuiting local areas, reducing runoff lag time and increasing storm stream runoff. The runoff producing mechanism, in which soil conditions, vegetation types and path networks are a complex interplay of contributing factors, may be relevant to other uplands, especially when they act as water reservoir or source area for possible flooding events. Therefore, upland management policies need to take into account that the heterogeneity of hillslopes at local scales has implications for storm runoff at the catchment scale. Copyright © 2014 John Wiley & Sons, Ltd.