This title appears in the Scientific Report :
2013
Please use the identifier:
http://hdl.handle.net/2128/5426 in citations.
Analysis of hydrological components of the Wüstebach catchment by means of stable isotope measurements
Analysis of hydrological components of the Wüstebach catchment by means of stable isotope measurements
Over the past decades, interpretation of changes in stable isotope signatures of catchment waters have beenused to assess hydrological flow paths under different flow conditions and estimating mean catchment residencetimes. However, despite of the many studies the timing, flow path, and source behav...
Saved in:
Personal Name(s): | Stockinger, Michael (Corresponding author) |
---|---|
Bogena, Heye / Lücke, Andreas / Wissel, Holger / Diekkrüger, Bernd / Vereecken, Harry | |
Contributing Institute: |
Agrosphäre; IBG-3 |
Imprint: |
2012
|
Conference: | EGU Generaly Assembly 2012, Vienna (Austria), 2012-04-22 - 2012-04-27 |
Document Type: |
Poster |
Research Program: |
Modelling and Monitoring Terrestrial Systems: Methods and Technologies |
Link: |
OpenAccess |
Publikationsportal JuSER |
Over the past decades, interpretation of changes in stable isotope signatures of catchment waters have beenused to assess hydrological flow paths under different flow conditions and estimating mean catchment residencetimes. However, despite of the many studies the timing, flow path, and source behavior of catchments are stillnot well understood. In this study we investigate the hydrological components of the Erkensruhr catchment (45km2), Germany, and the Wüstebach sub-catchment (10 ha2) using stable isotopes of water (D/H and Oxygen-18/Oxygen-16) as tracers. We present first results of a more than two-year long measurement campaign in theWüstebach catchment with respect to the magnitude and the temporal characteristics of isotope variations inprecipitation, throughfall, groundwater and the Wüstebach stream. Later research will also incorporate soil wateranalysis and focus on the isotopic behavior and the hydrological components (slow and fast runoff components)of the Erkensruhr catchment.First results demonstrate the expected seasonal effect on precipitation isotope ratio (Summer: -4.00h Oxygen-18toWinter: -11.00hOxygen-18) and that throughfall undergoes evaporation (differences up to +2.00hOxygen-18to precipitation). It is important to quantify this isotopic enrichment and the amount of throughfall to estimatethe effect of evaporative changes in throughfall compared to unchanged precipitation on the isotope ratios of theoutlets hydrograph. Both groundwater and streamflow samples show a tendency of lower isotope values over thecourse of the two-year long time series (linearly declining approximately -0.4h Oxygen-18). As precipitationdoes not show the same decline, ecological changes of the Wüstebach catchment might be the origin of this effect.A clear seasonal effect on streamflow can be observed at the source of the Wüstebach, with higher concentrationsin summer due to higher precipitation isotope concentrations and a fast decrease in concentration at the end ofwinter, probably due to snow melt. We observed a mixing effect of two separated stream sources. One sourceshows a clear seasonal behavior whereas the other source shows quasi-constant concentrations over time. Themixing of both sources leads to a dampening of the seasonal effect of isotope concentrations in the Wüstebachstream that does not disappear over the course of the measured stream (approximately 400 m). We argue thatthe invariable source is fed by deeper groundwater, whereas the seasonally variable source is fed by a shallowgroundwater aquifer.Our work indicates different groundwater sources for the Wüstebach river and shows an evaporative effect onthroughfall. A decline of isotope concentrations for streamwater and groundwater has been found that might bedue to ecological changes in the catchment. Future research will focus on hydrological modeling of the Wüstebachsub-catchment which will then be expanded to hydrological modeling of the Erkensruhr catchment. |