1. School of Earth, Atmosphere and Environment; Monash University; Clayton Victoria 3800 Australia
2. National Centre for Groundwater Research and Training; Flinders University; GPO Box 2100 Adelaide South Australia 5001 Australia
3. U.S. Geological Survey, Office of Groundwater, Branch of Geophysics; 11 Sherman Place, Unit 5015 Storrs CT 06269
4. Department of Earth Sciences; Syracuse University; 204 Heroy Geology Laboratory Syracuse NY 13244