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| Titel |
Quantifying water and salt fluxes in a lowland polder catchment dominated by boil seepage: a probabilistic end-member mixing approach |
| VerfasserIn |
P. G. B. Louw, Y. Velde, S. E. A. T. M. Zee |
| 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 ; 15, no. 7 ; Nr. 15, no. 7 (2011-07-07), S.2101-2117 |
| Datensatznummer |
250012882
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| Publikation (Nr.) |
 copernicus.org/hess-15-2101-2011.pdf |
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| Zusammenfassung |
| Upward saline groundwater seepage is leading to surface water salinization
of deep lying polders in the Netherlands. Identifying measures to reduce the
salt content requires a thorough understanding and quantification of the
dominant sources of water and salt on a daily basis. However, as in most
balance studies, there are large uncertainties in the contribution from
groundwater seepage. Taking these into account, we applied a probabilistic
(GLUE) end-member mixing approach to simulate two years of daily to weekly
observations of discharge, salt loads and salt concentration of water pumped
out of an artificially drained polder catchment area. We were then able to
assess the contribution from the different sources to the water and salt
balance of the polder and uncertainties in their quantification. Our
modelling approach demonstrates the need to distinguish preferential from
diffuse seepage. Preferential seepage via boils contributes, on average,
66 % to the total salt load and only about 15 % to the total water flux
into the polder and therefore forms the main salinization pathway. With the
model we were able to calculate the effect of future changes on surface
water salinity and to assess the uncertainty in our predictions.
Furthermore, we analyzed the parameter sensitivity and uncertainty to
determine for which parameter the quality of field measurements should be
improved to reduce model input and output uncertainty. High frequency
measurements of polder water discharge and weighted concentration at the
outlet of the catchment area appear to be essential for obtaining reliable
simulations of water and salt fluxes and for allotting these to the
different sources. |
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