GEOPHYSICAL RESEARCH LETTERS, VOL. ???, XXXX, DOI:10.1029/, The influence of migrating bedforms on the 1 velocity-intermittency structure of turbulent flow 2 over a gravel bed 3 Christopher J. Keylock, 1 Arvind Singh, 2 Efi Foufoula-Georgiou, 2 Corresponding author: C. J. Keylock, Sheffield Fluid Mechanics Group and Department of Civil and Structural Engineering, University of Sheffield, Sir Frederick Mappin Building, Mappin Street, Sheffield, S1 3JD, UK. (c.keylock@sheffield.ac.uk) 1 Department of Civil and Structural Engineering, Sheffield Fluid Mechanics Group, University of Sheffield, Sir Frederick Mappin Building, Mappin Street, Sheffield, S1 3JD, UK 2 Department of Civil Engineering, St. Anthony Falls Laboratory, and National Center for Earth-Surface Dynamics, , University of Minnesota, 2 Third Avenue SE, Minneapolis, MN, USA DRAFT March 22, 2014, 2:17am DRAFT