1. Sr. Project Engr., SCS Engrs., Inc., 4014 Long Beach Blvd., Long Beach, Calif. 90807; formerly Grad. Research Asst., Dept. of Civ. Engrg., Univ. of Illinois at Urbana-Champaign, Urbana, Ill. 61801
2. Assoc. Prof., Dept. of Civ. Engrg. and the Inst. for Environmental Studies, Univ. of Illinois at Urbana-Champaign, Urbana, Ill. 61801
3. Prof. of Environmental Engrg. and Head, Dept. of Civ. Engrg., Univ. of Illinois at Urbana-Champaign, Urbana, Ill. 61801