WATER RESOURCES RESEARCH, VOL. ???, XXXX, DOI:10.1029/, Flow over rough mobile beds: friction factor and vertical 1 distribution of the longitudinal mean velocity 2 Rui M.L. Ferreira, 1 M´ ario J. Franca, 2 Jo˜ ao G.A.B. Leal, 3 and Ant´ onio H. Cardoso 1 Rui M.L. Ferreira, Instituto Superior T´ ecnico, TU Lisbon, Av. Rovisco Pais 1049-001, Portugal (ruif@civil.ist.utl.pt) M´ ario J. Franca, Faculty of Science and Technology, Universidade Nova de Lisboa, Quinta da Torre, 2829-516 Caparica, Portugal (mfranca@fct.unl.pt) Jo˜ ao G.A.B. Leal, Faculty of Science and Technology, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal (jleal@fct.unl.pt) Ant´ onio H. Cardoso, Instituto Superior T´ ecnico, TU Lisbon, Av. Rovisco Pais 1049-001, Portugal (ahc@civil.ist.utl.pt) 1 CEHIDRO, Instituto Superior T´ ecnico, TU Lisbon, Portugal. 2 Faculty of Science and Technology & IMAR-CMA, New University of Lisbon, Portugal. 3 Faculty of Science and Technology & CEHIDRO, New University of Lisbon, Portugal. DRAFT July 5, 2011, 6:09pm DRAFT