Hi,

you may refer to:

Dutton A., Wilkinson B. H., Welker J. M., Bowen G. J., and Lohmann K. C.
(2005) Spatial distribution and seasonal variation in 18O/16O of modern
precipitation and river water across the conterminous United States.
Hydrological Processes 19, 4121-4146.

A PDF should be available from 

www.waterisotopes.org 

which is also a good place to start for questions around water isotopes.

regards,

Robert

--
Dr. Robert van Geldern
Section 3: Geochronology and Isotope Hydrology
Leibniz Institute for Applied Geosciences (GGA-Institute)

GEOZENTRUM HANNOVER
Stilleweg 2
30655 Hannover, Germany

Phone: +49-(0)511-643-2313
Fax: +49-(0)511-643-3665
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