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| Titel |
On the monitoring of antecedent wetness conditions across different scales |
| VerfasserIn |
Luca Brocca, Florisa Melone, Tommaso Moramarco, Sonia Heitz, Patrick Matgen, Laurent Pfister |
| 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 |
250040963
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| Zusammenfassung |
| The importance of soil moisture for hydrological applications is widely recognized. In recent
scientific literature many examples show that soil moisture is one of the most important state
variable to predict the rainfall-infiltration-runoff partitioning with reduced uncertainty.
Therefore, for stakeholders involved in flood management aiming at flood risk prevention and
mitigation, an accurate estimation of the initial state of the catchment wetness is of great
importance.
Several approaches are available to assess the wetness conditions in a catchment. They
range from simple approaches based on indicators of antecedent precipitation or
initial discharge to the ones more sophisticated using soil water balance models.
Recently, soil moisture and water level observations derived from ground networks have
been employed for this purpose. Additionally, soil moisture estimates derived from
sensors operating on satellite platforms can also be used. In this context, the main
scientific and operational issues can be summarized as follows. i) Which are the most
reliable indices or observations to be employed for the estimation of catchment
wetness conditions? ii) Which spatial and temporal resolution is required? iii) What is
the added value of the selected indices runoff prediction? This study attempts to
address the above questions by using rainfall-runoff data along with soil moisture and
groundwater level observations for several catchments located in the Alzette River Basin
(Grand-Duchy of Luxemburg). The individual catchment sizes range from 11 km2 to 425
km2. In particular, since 2005, soil moisture is monitored with a set of 40 classic
ECH2O DecagonTM soil moisture sensors at a depth ranging between 4 and 7 cm in
the small experimental Bibeschbach catchment (10.8 km2) located in the study
area.
Different indicators of soil moisture conditions prior to a storm event are used for setting
up the initial condition of different event-based rainfall-runoff models. In particular, simple
(e.g. Soil Conservation Service - Curve Number, bucket type model) and physically based
(e.g. Green-Ampt, Smith and Parlange) infiltration models are tested in order to have a more
general picture of results. The performance of different combinations of models and soil
moisture indicators, are evaluated with respect to flood hydrograph simulation at different
spatial scales using a large number of rainfall-runoff events occurred in the study
area.
For the investigated catchments, the obtained results besides to confirm the significant
role of the initial soil moisture conditions for flood simulation at different spatial
scales, have allowed to infer guidelines for soil moisture monitoring at catchment
scale in order to reduce the predictive uncertainty of rainfall-runoff modelling. |
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