Articles | Volume 11, issue 9
Nat. Hazards Earth Syst. Sci., 11, 2605–2615, 2011

Special issue: 11th Plinius Conference on Mediterranean Storms

Nat. Hazards Earth Syst. Sci., 11, 2605–2615, 2011

Research article 27 Sep 2011

Research article | 27 Sep 2011

Patterns of grain-size temporal variation of sediment transported by overland flow associated with moving storms: interpreting soil flume experiments

J. L. M. P. de Lima1,3, P. A. Dinis2,3, C. S. Souza3,7, M. I. P. de Lima3,5, P. P. Cunha2,3, J. M. Azevedo2,4, V. P. Singh6, and J. M. Abreu1,3 J. L. M. P. de Lima et al.
  • 1Department of Civil Engineering, Faculty of Science and Technology, University of Coimbra, 3030-788 Coimbra, Portugal
  • 2Department of Earth Sciences, Faculty of Science and Technology, University of Coimbra, 3000-272 Coimbra, Portugal
  • 3Institute of Marine Research (IMAR), Marine and Environmental Research Centre, Coimbra, Portugal
  • 4Geophysical Centre, Faculty of Science and Technology, Univ. of Coimbra, Avenida Dias da Silva, 3000-134 Coimbra, Portugal
  • 5Department of Forest Resources, Coimbra College of Agriculture, Polytechnic Institute of Coimbra, Bencanta, 3040-316 Coimbra, Portugal
  • 6Department of Biological and Agricultural Engineering & Department of Civil and Environmental Engineering, Texas A&M University, 321 Scoates Hall, 2117 TAMU, College Station, Texas 77843-2117, USA
  • 7BVP Engenharia, Av. Luiz Paulo Franco, 457, 5°, Belvedere, Belo Horizonte, Brazil

Abstract. This study describes and interprets the evolution of grain-size distribution of sediment yields generated in an experimental soil flume subjected to downstream and upstream moving rain storms. Results of laboratory experiments show that downstream moving storms cause more soil loss than do upstream moving storms. The pattern of sediment grain-size evolution in time during a runoff event exhibits a clear dependence on the direction of storm movement. A strong relationship between overland flow discharge and mean sediment size is found. Nevertheless, the mean grain-size of sediments transported during the rising limb of the hydrograph is coarser than during the recession limb of the hydrograph. This is more marked for downstream moving storms.