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| Titel |
Water budget determination for Northern groundwater dependent lakes using stable isotopes of water |
| VerfasserIn |
Elina Isokangas, Pekka Rossi, Anna-Kaisa Ronkanen, Björn Klöve |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250079784
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| Zusammenfassung |
| Understanding groundwater - surface water interaction is crucial in numerous water resources
management problems. Stable isotopes of water can bring understanding of this interaction
especially in catchment scale questions. In this study stable isotopes were used in a Finnish
esker aquifer (Lat 64.58Ë , Lon 26.50Ë ) where groundwater dependent lakes have suffered
from seasonal water level declines. Esker aquifers are the main groundwater reserves in
Finland used in water abstraction. In order to determine how hydrology of the lakes is
dependent on groundwater, the isotopic composition of oxygen and hydrogen was studied
from 36 sampling points during years 2010 to 2012. Samples were taken from 13
groundwater pipes, 11 lakes and 11 streams during winter, spring, summer and
autumn. Additionally local precipitation was sampled. The CRDS-method (Picarro
L2120-i analyzer) was used to analyze δ18O- and δ2H-values. The data from the
study was used to define the Local Meteoric Water Line of the site (δ2H = 7.60
δ18O + 6.70) and the groundwater line of the esker aquifer (δ2H = 7.59 δ18O +
4.79). The groundwater line of the esker aquifer differs from the groundwater line of
Finnish groundwaters (δ2H = 8.51 δ18O + 16.65) based on previous studies. This
emphasizes the importance of using local isotopic values when stable isotopes of
water are used in hydrological studies. Furthermore, the isotopic compositions
of the examined lakes differed enough from the isotopic composition of the local
groundwater to separate groundwater component in the lake hydrology. The results also
verified that evaporation from lakes in Northern Finland can be high enough to utilize
isotopic method for determination of groundwater and surface water interactions. |
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