MSc Earth Science
Geo-Ecological Dynamics
Literature Review
Factors influencing the quality of isotope-based hydrograph
separation
Ann-Hélène Faber
10457097
March, 2015
12 ECTS
Supervisor :
Dr. Erik Cammeraat
Co-assessor :
Dr. Emiel van Loon
Institute for Biodiversity and Ecosystem Dynamics
Abstract
Isotope–based hydrograph separation is an adequate tool to study runoff generation
during storm events. The use of stable water isotopes is based on a mass balance approach
to separate the different components of runoff. Isotope-based hydrograph separation is
however source of various limitations and uncertainties. There are limitations related to the
assumptions of the mass balance approach regarding isotopic variability and choice of runoff
components. However, there are ways to minimize these uncertainties by looking into
factors influencing the quality of hydrograph separation. The technical advancements of
measuring stable isotopes (spectrometry) in water allow for oxygen and hydrogen isotopes
to be measured simultaneously, directly in the field. Oxygen and hydrogen isotopes do not
necessarily provide redundant information, making it important to record both isotopic data.
Isotopic variation of precipitation, groundwater and runoff, and the choice of runoff
components provide information on reducing limitations related to the mass balance
equation. Performing a geochemical hydrograph separation together with an isotope-based
HS provides information on the dominant flow pathways. Electrical conductivity is a good
alternative to stable isotopes and can be easily measured in a continuous way. The
assumptions related to the mass balance equation might be limiting in application but there
are measures that can be taken to reduce these limitations by appreciating all the processes
and interactions occurring at a given study location and incorporating them into the
theoretical and experimental setup.
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