1. Postdoctoral Fellow, Center for Research in Water Resources, Pickle Research Campus, Bldg. 119, MC R8000, Univ. of Texas at Austin, Austin, TX 78712. E-mail: carlos_patino@mail.utexas.edu
2. Professor of Civil Engineering, Center for Research in Water Resources, Pickle Research Campus, Bldg. 119, MC R8000, Univ. of Texas at Austin, Austin, TX 78712. E-mail: Daene@aol.com
3. Professor of Civil Engineering, Center for Research in Water Resources, Pickle Research Campus, Bldg. 119, MC R8000, Univ. of Texas at Austin, Austin, TX 78712. E-mail: maidment@mail.utexas.edu