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| Titel |
A multi-tracer approach to determine groundwater discharge patterns in pristine peatlands |
| VerfasserIn |
Elina Isokangas, Pekka Rossi, Björn Klöve |
| 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 |
250089328
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| Publikation (Nr.) |
 EGU/EGU2014-3528.pdf |
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| Zusammenfassung |
| Changes in water flow patterns (e.g. due to ditching or pumping water) in the vicinity of a
peatland can affect its hydrology and ecology irreversibly. In Finland esker aquifers, often
used for water abstraction, discharge groundwater typically to peatlands. Locations of these
discharge zones are important for understanding peatland hydrology and ecology in general
and for predicting the impacts of groundwater abstraction. In this study, a Finnish
pristine peatland connected to an esker aquifer was sampled for natural tracers (stable
water isotopes, electrical conductivity and temperature, n = 55) from two depths
(30 cm and under the peat layer) in the summer of 2013. The peat levels of the
sampling points varied between 0.57 – 1.00 m. In addition, hydraulic conductivity
measurements (n = 13) and airborne thermal imaging were carried out and local
precipitation was sampled for stable water isotopes. The CRDS-method (Picarro L2120-i
analyzer) was applied to analyze δ18O and δ2H values. Local Meteoric Water Line
(LMWL) was determined using precipitation from Nuoritta (17 km west from the
study site), δ2H = 7.24 δ18O + 7.94 (R2 = 0.996). Ranges for δ18O and δ2H of
peatland water were, -13.3 o– -10.3 oand -96.1 o– -75.6 o respectively.
Furthermore, electrical conductivity varied between 19.6 – 192.8 mS m-1, hydraulic
conductivity between 1.7•10-8 – 5.0•10-4 m s-1 and temperature between 6.1
– 16.8 °C. Natural tracers were used for identifying water flow patterns of the
peatland. Interpretation of the results was complicated due to a stream flowing
through the studied peatland. However, groundwater discharge zones were observed
alongside the esker and also further away from the esker in the peatland area. This
research shows that combination of high-resolution thermal images and discrete
field measurements will result in more reliable and precise water flow patterns. |
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