1. Prof. of Civ. Engrg., W. M. Keck Laboratory of Hydraulics and Water Resources, Calif. Inst. of Tech., Pasadena, Calif.
2. Sr. Scientist, Tetra Tech, Inc., Pasadena, Calif.; formerly Research Fellow, W. M. Keck Laboratory of Hydraulics and Water Resources, Calif. Inst. of Tech., Pasadena, Calif.