1. U.S. Geological Survey, Denver Federal Center, Denver, Colorado 80225, USA
2. 619 Winney Hill Road, Oneonta, New York 13820, USA
3. Department of Earth and Atmospheric Sciences, State University of New York, Oneonta, New York 13820-4015, USA
4. U.S. Geological Survey, Washington Water Science Center, Tacoma, Washington 98402, USA