Earth Surf. Dynam., 2, 469480, 2014www.earth-surf-dynam.net/2/469/2014/doi:10.5194/esurf-2-469-2014 Author(s) 2014. CC Attribution 3.0 License.The impact of particle shape on the angle of internalfriction and the implications for sediment dynamicsat a steep, mixed sandgravel beachN. Stark1,*, A. E. Hay1, R. Cheel1, and C. B. Lake21Dalhousie University, Department of Oceanography, Halifax, Canada2Dalhousie University, Department of Civil Engineering, Halifax, Canada*now at: Virginia Tech, Department of Civil and Environmental Engineering, Blacksburg, VA, USACorrespondence to: N. Stark (ninas@vt.edu)Received: 14 October 2013 Published in Earth Surf. Dynam. Discuss.: 10 December 2013Revised: 18 July 2014 Accepted: 24 July 2014 Published: 27 August 2014Abstract. The impact of particle shape on the angle of internal friction, and the resulting impact on beachsediment dynamics, is still poorly understood. In areas characterized by sediments of specic shape, particularlynon-rounded particles, this can lead to large departures from the expected sediment dynamics. The steep slope(1 : 10) of the mixed sandgravel beach at Advocate Harbour is stable in large-scale morphology over decades,despite a high tidal range of 10 m or more, and intense shore-break action during storms. The Advocate sand(d