Integrated simulation of daily isotope variability at two spatial scales in a nested agricultural catchment
Abstract
This work presents 19 months of stable isotope (deuterium and oxygen-18) data to enhance understanding of water and solute transport at two spatial scales (2.3 km2 and 122 km2) in the lowland Lunan catchment, North East Scotland. Daily precipitation and stream isotope data, weekly lake water and spring isotope data and monthly groundwater isotope data revealed important insights into flow pathways and mixing of water at both scales. This unique tracer data set facilitated the conceptualization of a lumped catchment-scale flow-tracer model. The incorporation of hydrological and mixing processes based on these data improved simulations of the stream isotope response. In particular, a deep groundwater flow path and upstream lake isotope dynamics, susceptible to evaporative fractionation, appeared to have an important influence on the downstream response and isotope composition. Additionally the isotope data helped to internally constrain state variables of the model. The isotope data successfully aided model conceptualization and calibration in the quest for a simple water and solute transport model with improved representation of the underlying process mechanisms.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2010
- Bibcode:
- 2010AGUFM.H53J..05B
- Keywords:
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- 0496 BIOGEOSCIENCES / Water quality;
- 1847 HYDROLOGY / Modeling