1. Earth Science Division, Directorate for Geosciences, National Science Foundation, 4201 Wilson Boulevard, Arlington, Virginia 22230
2. Las Vegas Springs Preserve Project, Las Vegas Valley Water District, 1001 South Valley View Boulevard, Las Vegas, Nevada 89153
3. Water Resources Management Program and Department of Geoscience, University of NevadaLas Vegas, 4505 Maryland Parkway, Las Vegas, Nevada 89154-4029