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| Titel |
Sediment budget variation at watershed scale due to anthropogenic pressures, and its relationship to coastal erosion |
| VerfasserIn |
Antonello Aiello, Maria Adamo, Filomena Canora |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250099720
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| Publikation (Nr.) |
 EGU/EGU2014-15532.pdf |
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| Zusammenfassung |
| The transfer of sediments from hydrographic basins towards the coast is a significant pathway
of material transfer on Earth. In sedimentary environment, the main portion of sediment that
enters the coastal areas is derived originally from erosion in the coastal watersheds.
Extensive anthropogenic pressures carried out within coastal basins have long shown
negative impacts on littoral environments. In fluvial systems, sediments trapped behind
dams and in-stream gravel mining cause the reduction in sediment supply to the
coast.
Along the Jonian littoral of the Basilicata Region (southern Italy), natural coastal
processes have been severely disrupted since the second half of the 20th century as a
result of riverbed sand and gravel mining and dam construction, when economic
advantages were measured in terms of the development of infrastructure, water storage,
and hydropower production for the agricultural, industrial and socio-economic
development of the area. Particularly, the large numbers of dams and impoundments that
have been built in the hydrographic basins have led a signi?cant reduction on river
sediment loads. As a result, the Jonian littoral is experiencing a catalysed erosion
phenomenon.
In order to increase understanding of the morpho-dynamics of the Jonian littoral
environment and more fully appreciate the amount of coastal erosion, an evaluation of the
sediment budget change due to dam construction within the hydrographic basins of the
Basilicata Region needs to be explored. Since quantitative data on decadal trends in river
sediment supply before and after dam construction are lacking, as well as updated dam
silting values, river basin assessment of the spatial patterns and estimated amount of
sediment erosion and deposition are important in evaluating changes in the sediment
budget. As coastal areas are being affected by an increasing number of population
and socio-economic activities, the amount of sediment deficit at the littoral can
permit to forecast coastline fluctuations caused by such anthropogenic interventions.
These are valuable information for both the management of and development of
future plans for coastal environments and for reducing exposure risk to coastal
erosion.
The purpose of this study was to compare and to evaluate the suitability of the RUSLE
(Revised Universal Soil Loss Equation), RUSLE 3D and USPED (Unit Stream Power-based
Erosion Deposition) models in assessing the sediment budget variation at watershed
scale. In order to assess the rate of net soil erosion, the three models were applied to
the Bradano river basin and to the sub-basin subtended by the San Giuliano Dam.
To this end, digital terrain model, products derived from satellite remote sensing
(multi-temporal Landsat imagery), soil texture maps and ancillary data were integrated and
processed in a GIS. To test the models, the computed soil erosion rates were integrated
over the San Giuliano sub-basin surface, and compared with the dam silting value
provided by an interregional authority responsible for its management. The three
models have proven to be effective in quantifying the soil erosion at watershed scale. |
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