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| Titel |
Analysis and simulation of nutrient retention and management for a lowland river-lake system |
| VerfasserIn |
D. Kneis, R. Knoesche, A. Bronstert |
| 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 ; 10, no. 4 ; Nr. 10, no. 4 (2006-08-08), S.575-588 |
| Datensatznummer |
250008143
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| Publikation (Nr.) |
 copernicus.org/hess-10-575-2006.pdf |
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| Zusammenfassung |
| In the context of the European Water Framework Directive, we studied the possible impact of
reduced emissions on phosphorus and nitrogen concentrations in a lowland river-lake system (Havel
River, Germany). As a prerequisite, we quantified the retention of nutrients in the river from mass balances and deduced
its seasonal variation. We detected that about 30% of the total nitrogen input is retained within the surveyed river section.
In contrast, phosphorus release from sediments was shown to cause a considerable increase in present P concentrations.
Average net phosphorus release rates of about 20 mg P m−2 d−1 in late summer were estimated for the Havel
Lakes. Based on the observed patterns of N retention and P release we parametrized a newly developed water quality
simulation program (TRAM), which allows alternative model approaches of different complexity to be implemented and
tested. To account for the future trend of internal P loading, the phosphorus excess in lake sediments was estimated
from core samples and included in the model as a state variable. For analyzing scenarios of reduced nutrient
emissisions, the water quality simulation program was linked to mesoscale hydrological catchment models for
the first time. From scenario simulations we conclude that internal P loading is likely to counteract efforts
of emission control for decades. Even by significant reductions in external P loads, a persistent phosphorus
limitation of primary production can hardly be established in the analyzed time frame of 13 years. Though in
the short run a continued reduction in nitrogen loads appears to be the more promising approach of eutrophication
management, we recommend enhanced efforts to diminish both N and P emissions. |
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