Sheila F Murphy¹, Richard Blaine McCleskey², JoAnn M Holloway³, Deborah A Martin¹ and Jeffrey H Writer⁴, (1)USGS, Boulder, CO, United States, (2)U.S. Geological Survey, Water Mission Area, Boulder, CO, United States, (3)USGS, Geology, Geophysics and Geochemistry Science Center, Denver, CO, United States, (4)University of Colorado at Boulder, Education, Boulder, CO, United States