An isotopic view of water and nitrate transport through the vadose zone in Oregon’s southern Willamette Valley’s Groundwater Management Area

J Renee Brooks1, Susanna Pearlstein2, Steve Hutchins3, Barton R Faulkner3, William Rugh1, Kenneth Willard4, Rob Coulombe5 and Jana Compton6, (1)U.S. Environmental Protection Agency, Pacific Ecological Systems Division, Corvallis, United States, (2)University of Alaska Fairbanks, Fairbanks, AK, United States, (3)U.S. Environmental Protection Agency, Groundwater Characterization and Remediation Division, Ada, United States, (4)Environmental Protection Agency Corvallis, Western Ecology Division, Corvallis, OR, United States, (5)CSS, Corvallis, OR, United States, (6)U.S. Environmental Protection Agency, Office of Research and Development, Corvallis, United States