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The impact of upland land management on flooding: results from an improved pasture hillslope
Author(s) -
Marshall Miles R.,
Francis Oliver J.,
Frogbrook Zoe L.,
Jackson Bethanna M.,
McIntyre Neil,
Reynolds Brian,
Solloway Imogen,
Wheater Howard S.,
Chell Joanne
Publication year - 2008
Publication title -
hydrological processes
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.222
H-Index - 161
eISSN - 1099-1085
pISSN - 0885-6087
DOI - 10.1002/hyp.7157
Subject(s) - surface runoff , hydrology (agriculture) , environmental science , antecedent moisture , pasture , macropore , flood myth , hydraulic conductivity , drainage basin , soil water , soil science , runoff curve number , geology , geography , ecology , forestry , geotechnical engineering , mesoporous material , biochemistry , chemistry , cartography , archaeology , biology , catalysis
In response to growing concern about impacts of upland agricultural land management on flood risk, an intensely instrumented experimental catchment has been established at Pontbren, a sheep‐farmed headwater catchment of the River Severn, UK. Primary aims are to develop understanding of the processes governing flood generation and the associated impacts of land management practices, and to bridge the gap between process understanding and ability to predict effects on downstream flooding. To achieve this, the experiment is designed to operate at plot (∼100 m 2 ), hillslope (∼0·1 km 2 ) and small catchment scale (∼10 km 2 ). Hillslope‐scale data, from an under‐drained, agriculturally ‘improved’ pasture, show that drain flow is a dominant runoff process. However, depending on antecedent moisture conditions, overland flow may exceed drain flow rates and can be an important contributor to peak flow runoff at the hillslope‐scale. Flow, soil tension data and tracer tests confirm the importance of macropores and presence of perched water tables under ‘normal’ wet conditions. Comparisons of pasture runoff with that from within a 10 year‐old tree shelterbelt show significantly reduced overland flow due to the presence of trees and/or absence of sheep. Comparisons of soil hydraulic properties show significant increases in hydraulic conductivity and saturated moisture content of soil under trees compared to adjacent improved pasture. Copyright © 2008 John Wiley & Sons, Ltd.