1. Director of Roman Aqueduct Studies, Wright Paleohydrological Institute, 2490 W. 26th Avenue, Suite 100A, Denver, CO 80211 (corresponding author).
2. Research Associate, Wright Paleohydrological Institute, 2490 W. 26th Avenue, Suite 100A, Denver, CO 80211; and Ph.D. Student, Environmental Fluid Mechanics Laboratory, Stanford Univ., Y2E2, 473 Via Ortega, Office M-17, Stanford, CA 94305.