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| Titel |
Wetland restoration and nitrate reduction: the example of the peri-urban wetland of Vitoria-Gasteiz (Basque Country, North Spain) |
| VerfasserIn |
C. García-Linares, M. Martínez-Santos, V. Martínez-Bilbao, J. M. Sánchez-Pérez, I. Antiguedad |
| 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 ; 7, no. 1 ; Nr. 7, no. 1, S.109-121 |
| Datensatznummer |
250004425
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| Publikation (Nr.) |
 copernicus.org/hess-7-109-2003.pdf |
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| Zusammenfassung |
| Changes in land use and agricultural intensification caused wetlands on the
quaternary aquifer of Vitoria-Gasteiz (Basque Country) to disappear some years ago and
nitrate concentration in groundwaters increased very quickly. The Basque Government
recently declared the East Sector of this aquifer a Vulnerable Zone according to the
91/676/CEE European Directive. Recently, the wetlands have been restored through the
closure of the main drainage ditches, the consequent elevation of the water table and
the abondonment of agricultural practices near the wetlands. This is the case of the
Zurbano wetland. Restoration has allowed the recovery of its biogeochemical function,
which has reduced nitrate concentrations in waters. Nitrate concentrations which exceed
50 mg l–1 in groundwaters entering into the wetland are less than
10 mg l–1 at the outlet. Conditions in the wetland are conducive to
the loss of
nitrates: organic matter rich wetted soils, clay presence allowing a local semiconfined
flow and very low hydraulic gradient. Water quality monitoring at several points around
the wetland showed the processes involved in nitrate loss, although some aspects still
remain unresolved. However, during storm events, the wetland effectively reduces the
nitrate concentration entering the Alegria River, the most important river on the
quaternary aquifer.
Keywords: restored wetland functionality, nitrate losses, Basque Country |
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