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| Titel |
Use of soil moisture and water table data for rainfall-runoff modelling in alpine catchments |
| VerfasserIn |
Luca Brocca, Daniele Penna, Silvia Barbetta, Florisa Melone, Tommaso Moramarco, Alberto Gobbi |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250035923
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| Zusammenfassung |
| Prediction of hydrologic response is particularly difficult in alpine regions where data are
sparse and the spatial variability of both precipitation and physical controls on runoff
generation is considerable. Moreover, alpine catchments are frequently affected by small
scale flash floods, which are usually responsible for shallow landsliding and debris flow
triggering. Therefore, improving the understanding of the rainfall-runoff processes occurring
in these regions represents a relevant scientific topic for hydrologists and operators involved
in hydro-geological risk mitigation. Studies undertook in small experimental areas
where rainfall and discharge measures and additional hydrological variables are
recorded, can address this issue. In this work, soil moisture and water table data are
used along with the commonly used rainfall runoff and temperature variables in
order to investigate the hydrologic behaviour of the Vauz creek basin (1.9 km2)
located in the central-eastern Italian Alps. Beside this, two micro subcatchments
(Bridge Creek catchment and Larch Creek catchment, of area 0.11 and 0.032 km2,
respectively) were analyzed in order to investigate the influence of spatial and temporal
dynamics of soil moisture and water table on runoff response at different scales.
Soil water content and groundwater level have been continuously monitored in the
snow-free period (from May to September) since summer 2005 with a sub-hourly time
resolution.
A continuous rainfall-runoff model (MISDc), developed for the simulation of flood events
at the hourly (or less) time scale, was applied to the experimental subcatchments. The model
consists of two components: i) a soil water balance model that simulates the soil moisture
temporal pattern; ii) an event-based rainfall-runoff model for flood hydrograph simulation
whose initial conditions are determined by the first component. By coupling the
two models through an experimentally-derived relationship, a single continuous
rainfall-runoff model characterized by a parsimonious and robust structure is derived.
The model requires, as input data, meteorological variables routinely measured
(rainfall and air temperature) and incorporates a limited number of parameters. The
simplicity of the model and the low number of parameters involved makes MISDc an
appropriate tool to investigate the effects of different data source on the hydrologic
response.
For the analysis, the ancillary soil moisture and water table data were used both for the
model calibration and for its validation. The modification of the model structure was also
tested in order to better reproduce not only the discharge hydrograph but also the dynamics of
subsurface water as inferred through the ancillary data set. The results show a good
agreement between the simulated and the measured data in different hydrological conditions
and highlight the paramount role of antecedent soil moisture conditions on the hydrologic
response of alpine catchments. Moreover, in order to extend the results observed for this
small experimental areas to larger catchments, the need to establish an appropriate spatial and
temporal resolution of soil moisture and groundwater measurements was underlined. |
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