Does drought alter hydrological functions in forest soils?
Climate change is expected to impact the water cycle and severely affect precipitation patterns across central Europe and in other parts of the world, leading to more frequent and severe droughts. Usually when projecting drought impacts on hydrological systems, it is assumed that system properties,...
Main Authors: | , , |
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Format: | Article |
Language: | English |
Published: |
Copernicus Publications
2016-04-01
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Series: | Hydrology and Earth System Sciences |
Online Access: | http://www.hydrol-earth-syst-sci.net/20/1301/2016/hess-20-1301-2016.pdf |
Summary: | Climate change is expected to impact the water cycle and severely affect
precipitation patterns across central Europe and in other parts of the
world, leading to more frequent and severe droughts. Usually when projecting
drought impacts on hydrological systems, it is assumed that system
properties, like soil properties, remain stable and will not be affected by
drought events. To study if this assumption is appropriate, we address the
effects of drought on the infiltration behavior of forest soils using dye
tracer experiments on six sites in three regions across Germany, which were
forced into drought conditions. The sites cover clayey-, loamy- and sandy-textured soils. In each region, we compared a deciduous and a coniferous
forest stand to address differences between the main tree species. The
results of the dye tracer experiments show clear evidence for changes in
infiltration behavior at the sites. The infiltration changed at the clayey
plots from regular and homogeneous flow to fast preferential flow. Similar
behavior was observed at the loamy plots, where large areas in the upper
layers remained dry, displaying signs of strong water repellency. This was
confirmed by water drop penetration time (WDPT) tests, which revealed, in
all except one plot, moderate to severe water repellency. Water repellency
was also accountable for the change of regular infiltration to fingered flow
in the sandy soils. The results of this study suggest that the
<i>drought history</i> or, more generally, the climatic conditions of a soil in the past are more important than the actual antecedent soil moisture status
regarding hydrophobicity and infiltration behavior; furthermore, drought
effects on infiltration need to be considered in hydrological models to
obtain realistic predictions concerning water quality and quantity in runoff
and groundwater recharge. |
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ISSN: | 1027-5606 1607-7938 |