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| Titel |
Landscape elements and river chemistry as affected by river regulation – a 3-D perspective |
| VerfasserIn |
E. Smedberg, C. Humborg, M. Jakobsson, C.-M. Mörth |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 13, no. 9 ; Nr. 13, no. 9 (2009-09-09), S.1597-1606 |
| Datensatznummer |
250011991
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| Publikation (Nr.) |
 copernicus.org/hess-13-1597-2009.pdf |
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| Zusammenfassung |
| We tested the hypothesis whether individual land classes within a river
catchment contribute equally to river loading with dissolved constituents or
whether some land classes act as "hot spots" to river loading and if so,
are these land classes especially affected by hydrological alterations. The
amount of land covered by forests and wetlands and the average soil depth
(throughout this paper soil refers to everything overlying bedrock i.e.
regolith) of a river catchment explain 58–93% of the variability in total
organic carbon (TOC) and dissolved silicate (DSi) concentrations for 22
river catchments in Northern Sweden. For the heavily regulated
Luleälven, with 7 studied sub-catchments, only 3% of the headwater
areas have been inundated by reservoirs, some 10% of the soils and
aggregated forest and wetland areas have been lost due to damming and
further hydrological alteration such as bypassing entire sub-catchments by
headrace tunnels. However, looking at individual forest classes, our
estimates indicate that some 37% of the deciduous forests have been
inundated by the four major reservoirs built in the Luleälven
headwaters. These deciduous forest and wetlands formerly growing on top of
alluvial deposits along the river corridors forming the riparian zone play a
vital role in loading river water with dissolved constituents, especially
DSi. A digital elevation model draped with land classes and soil depths
which highlights that topography of various land classes acting as hot spots
is critical in determining water residence time in soils and biogeochemical
fluxes. Thus, headwater areas of the Luleälven appear to be most
sensitive to hydrological alterations due to the thin soil cover (on average
2.7–4.5 m) and only patchy appearance of forest and wetlands that were
significantly perturbed. Hydrological alterations of these relatively small
headwater areas significantly impacts downstream flux of dissolved
constituents and their delivery to receiving water bodies. |
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