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| Titel |
Analysis on underlying connectivity mechanisms of a mesoscale dryland river basin, NE Spain |
| VerfasserIn |
Susanna Werth, Sandra Werb, Till Francke, Axel Bronstert |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250054544
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| Zusammenfassung |
| Reliable, comprehensive and long-term measurements of sediment fluxes are of high need,
for a successful model development and modelling of erosion, sediment transport, retention
and remobilization in order to better understand the (inter-)relation of these sedimentological
transport processes, hereafter named connectivity mechanisms. A lack of knowledge exists
specifically for regions of dry climates. Here, connectivity phenomena depend on static
geomorphologic and vegetation characteristics of the basin (e.g., slope, elevation, soil,
exposure or vegetation) as well as dynamic patterns like rainfall events, which often exhibit a
high variability in space and time (rainfall intensity and duration). The dryland
catchment of investigation is the Iábena (445 km2) river basin, located in the central
Spanish Pyrenees, North-East Spain. The largest sediment source is a badland area
within the middle reaches. The river discharges into the Barasona reservoir, which
provides important water supply for the region’s agriculture. The capacity of the
reservoir is gradually reduced by sediment delivery of the river basin. This causes the
necessity of investigation of erosion and sediment transport processes. So far, erosion
studies for the region concentrated on the quantification of sediment concentration
and delivery, sediment budgets and adjacent modelling for management purposes.
The undertaken mesoscale conceptual modelling is of insufficient accuracy for
predictions of erosion rates, most likely due to the insufficient conceptualization of the
connectivity between hillslope and main stream. Furthermore, potential characteristics and
locations of temporary sediment storages within the basin have yet to be investigated in
detail. Consequently, this study provides a spatial analysis of unknown static and
dynamic connectivity features within the river basin. The analysis bases on a Digital
Elevation Model (DGM), maps of vegetation distribution, soil type and geology.
Furthermore, rainfall and discharge records from different periods are studied. Regarding
the individual features and their combination, potential regions of strong or weak
connectivity to the main stream will be extracted, hence giving an insight into the
connectivity-characteristics of the basin’s sub-regions. The results will serve as an input for
the design of a hydrological and sedimentological measurement network to be installed
within the Isábena basin. And finally they will direct toward an improved conceptual
modelling of sedimentological connectivity for mesoscale dryland river basins. |
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