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| Titel |
Effects of Soil Moisture Thresholds in Runoff Generation in two nested gauged basins |
| VerfasserIn |
M. Fiorentino, A. Gioia, V. Iacobellis, S. Manfreda, M. R. Margiotta, B. Onorati, A. R. Rivelli, A. Sole |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250030225
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| Zusammenfassung |
| Regarding catchment response to intense storm events, while the relevance of antecedent
soil moisture conditions is generally recognized, the role and the quantification of
runoff thresholds is still uncertain. Among others, Grayson et al. (1997) argue that
above a wetness threshold a substantial portion of a small basin acts in unison and
contributes to the runoff production. Investigations were conducted through an
experimental approach and in particular exploiting the hydrological data monitored
on “Fiumarella of Corleto” catchment (Southern Italy). The field instrumentation
ensures continuous monitoring of all fundamental hydrological variables: climate
forcing, streamflow and soil moisture. The experimental basin is equipped with two
water level installations used to measure the hydrological response of the entire
basin (with an area of 32 km2) and of a subcatchment of 0.65 km2. The aim of the
present research is to better understand the dynamics of soil moisture and the runoff
generation during flood events, comparing the data recorded in the transect and the
runoff at the two different scales. Particular attention was paid to the influence
of the soil moisture content on runoff activation mechanisms. We found that, the
threshold value, responsible of runoff activation, is equal or almost to field capacity. In
fact, we observed a rapid change in the subcatchment response when the mean
soil moisture reaches a value close to the range of variability of the field capacity
measured along a monitored transect of the small subcatchment. During dry periods
the runoff coefficient is almost zero for each of the events recorded. During wet
periods, however, it is rather variable and depends almost only on the total rainfall.
Changing from the small scale (0.65 km2) up to the medium scale (represented by the
basin of 32 km2) the threshold mechanism in runoff production is less detectable
because masked by the increased spatial heterogeneity of the vegetation cover and soil
texture. |
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