A tale of two isotopes: differences in hydrograph separation for a runoff event when using δD versus δ18O
Article first published online: 20 APR 2009
Copyright © 2009 John Wiley & Sons, Ltd.
Volume 23, Issue 14, pages 2095–2101, 1 July 2009
How to Cite
Lyon, S. W., Desilets, S. L. E. and Troch, P. A. (2009), A tale of two isotopes: differences in hydrograph separation for a runoff event when using δD versus δ18O. Hydrol. Process., 23: 2095–2101. doi: 10.1002/hyp.7326
- Issue published online: 17 JUN 2009
- Article first published online: 20 APR 2009
- Manuscript Accepted: 10 MAR 2009
- Manuscript Received: 14 OCT 2008
- hydrograph separation;
- stable water isotopes;
- off-axis integrated cavity output spectroscopy
It is often assumed that stable water isotopes (δD and δ18O) provide redundant information for a given sample of water. In this note we illustrate that the choice of isotope used may influence the resultant hydrograph separation. This is especially true in light of the spatial and temporal variability in the isotopic composition of rainfall water at the catchment scale. We present several possible hydrograph separations based on both δD and δ18O observed in rainfall for a single runoff event occurring in the southwest USA. This study demonstrates the potential of using both stable water isotopes by showing that δD and δ18O may provide unique information for catchment hydrologists. We also report on the utility of new technology capable of simultaneous measurements of both δD and δ18O using off-axis integrated cavity output spectroscopy (OA-ICOS) methods. This may be of interest to catchment hydrologists seeking to incorporate this type of equipment into their laboratory. Copyright © 2009 John Wiley & Sons, Ltd.