1. Res. Engr., Inst. of Hydr. Engrg. and Water Resour. Mgmt. (IWW), Aachen Univ. of Technology, Kreuzherrenstr., 52056 Aachen, Germany.
2. Prof., School of Civ. and Envir. Engrg., Hollister Hall, Cornell Univ., Ithaca, NY 14853. E-mail: DPL3@cornell.edu
3. Proj. Mgr., RWE Energie AG, 45117, Essen, Germany.