1. Drainage Designer, Drainage Group, Kiewit Engineering Group, Inc., 9401 Renner Blvd., Lenexa, KS 66219.
2. Professor, Dept. of Civil and Environmental Engineering, Brigham Young Univ., 368 Clyde Bldg., Provo, UT 84602 (corresponding author).
3. Vice-President, Holistic Engineering and Land Management, Inc., 14040 N. Cave Creek Rd., Suite 104, Phoenix, AZ 85022.