Calculations of groundwater inflows to streams, assuming that groundwater and surface runoff are the two major reservoirs, using environmental tracers (e.g., Cl or Rn) and physical techniques based on analysing stream hydrographs commonly yield different results. In general, geochemical techniques produce lower estimates of baseflow than physical techniques and, even within the suite of geochemical tracers; conservative tracers such as Cl may produce different estimates of baseflow than tracers that have a time-dependence (e.g., Rn).
Their studies integrate work from several river catchments in Victoria, Australia (Ovens, Barwon, Tambo, Nicholson, Mitchell, Avon, and Gellibrand). These catchments have well-constrained river flows, groundwater geochemistry and river and bank geochemistry (major ions, stable isotopes, and Rn). This combined data allows for the quantification of water inputs to the streams from reservoirs such as the river banks and the unsaturated zone and to gain an understanding of the impacts of sampling prior to or following flood peaks on the stream geochemistry results.
With these studies we aim to provide a more robust understanding of groundwater-surface water interaction in these catchments.About the speaker
Harald Hofmann is a Research Fellow at Monash University and is also part of the NCGRT and GEIF programs. Prior to undertaking his PhD at Monash (2007-2011), Harald was employed as a researcher in the Luxembourg Water Bureau (2003-2006) and the Luxembourg Research Centre Henri Tudor as Research & Development Engineer. He has also taken an active role in humanitarian projects, particularly in Haiti. He has expertise in application of geochemical tracers to understanding groundwater-surface water interaction.
Come join us
Date: 15 May 2012
Time: 5:30pm meet and greet for a 6pm start
Location: Parsons Brinkerhoff (15/28 Freshwater Place, Southbank)
No need to RSVP
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Reconciling geochemical and physical tracers of groundwater-stream interactions