A multi-technique approach to determine temporal and spatial variability of groundwater-stream water exchange

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Koruk K., Yılmaz K. K., Akyürek S. Z., Binley A.

EGU, Vienna, Austria, 7 - 12 April 2019, vol.21, pp.1080

  • Publication Type: Conference Paper / Summary Text
  • Volume: 21
  • City: Vienna
  • Country: Austria
  • Page Numbers: pp.1080
  • Middle East Technical University Affiliated: Yes


Characterizing the spatio-temporal distribution of groundwater-surface water exchange fluxes are of paramountimportance in understanding catchment behavior as well as biogeochemical and ecological status. The objectiveof this study is to quantify the spatio-temporal distribution of the exchange fluxes along the Cakit Stream(Nigde, Turkey) through coupling a set of geophysical techniques and in-stream measurements in a hierarchicalmanner. First, we conducted electromagnetic induction (EM) surveys over long reaches of the Cakit Stream topinpoint potential groundwater upwelling sections along the streambed. EM anomalies guided our focus to a 600meter-long reach of the stream. Along this selected reach, fiber-optic distributed temperature sensing system wasutilized to investigate top-of-the-streambed-temperature profiles at fine spatial and temporal scales. Furthermore,nested piezometers and vertical temperature profiles (using iButtons) were installed at three potential locations toinvestigate vertical hydraulic gradients and exchange fluxes. Water quality parameters were also measured alongthe reach in-stream and in the piezometers. Our results indicate that the downstream sections of the streambed arecharacterized by downwelling fluxes regardless of the season, whereas seasonal factors control the direction andmagnitude of the exchange fluxes along upstream sections. In this presentation we discuss our results in detail andhighlight the effect of streamflow discharge and streambed conditions on the performance of various techniquesutilized in this study.