1. Professor, Dept. Geology and Geological Engineering, Colorado School of Mines, 1500 Illinois St., Golden, CO 80401; Director, International Ground-Water Modeling Center (corresponding author). E-mail: epoeter@mines.edu
2. Associate Professor, Environmental Science and Engineering Division, Colorado School of Mines, 1500 Illinois St., Golden, CO 80401. E-mail: jmccray@mines.edu