 |
| Titel |
The influence of soil moisture on threshold runoff generation processes in an alpine headwater catchment |
| VerfasserIn |
D. Penna, H. J. Tromp-van Meerveld, A. Gobbi, M. Borga, G. Dalla Fontana |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1027-5606
|
| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 15, no. 3 ; Nr. 15, no. 3 (2011-03-01), S.689-702 |
| Datensatznummer |
250012674
|
| Publikation (Nr.) |
 copernicus.org/hess-15-689-2011.pdf |
|
|
|
|
|
| Zusammenfassung |
| This study investigates the role of soil moisture on the threshold runoff
response in a small headwater catchment in the Italian Alps that is
characterised by steep hillslopes and a distinct riparian zone. This study
focuses on: (i) the threshold soil moisture-runoff relationship and the
influence of catchment topography on this relation; (ii) the temporal
dynamics of soil moisture, streamflow and groundwater that characterize the
catchment's response to rainfall during dry and wet periods; and (iii) the
combined effect of antecedent wetness conditions and rainfall amount on
hillslope and riparian runoff. Our results highlight the strong control
exerted by soil moisture on runoff in this catchment: a sharp threshold
exists in the relationship between soil water content and runoff
coefficient, streamflow, and hillslope-averaged depth to water table. Low
runoff ratios were likely related to the response of the riparian zone,
which was almost always close to saturation. High runoff ratios occurred
during wet antecedent conditions, when the soil moisture threshold was
exceeded. In these cases, subsurface flow was activated on hillslopes, which
became a major contributor to runoff. Antecedent wetness conditions also
controlled the catchment's response time: during dry periods, streamflow
reacted and peaked prior to hillslope soil moisture whereas during wet
conditions the opposite occurred. This difference resulted in a hysteretic
behaviour in the soil moisture-streamflow relationship. Finally, the
influence of antecedent moisture conditions on runoff was also evident in
the relation between cumulative rainfall and total stormflow. Small storms
during dry conditions produced low stormflow amounts, likely mainly from
overland flow from the near saturated riparian zone. Conversely, for
rainfall events during wet conditions, higher stormflow values were observed
and hillslopes must have contributed to streamflow. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|