Mo-i-Rana - September 2002 Dam-break floods and sediment movement 1 IMPACT - WP4 Dam-break induced floods and sediment movement IMPACT - WP4 Dam-break induced floods and sediment movement Progress report Université catholique de Louvain Yves Zech, Benoit Spinewine and Sandra Soares Frazão

Mo-i-Rana - September 2002 Dam-break floods and sediment movement 2 Aims and objectives Improve the prediction of the motion of sediments in association with catastrophic floods

Mo-i-Rana - September 2002 Dam-break floods and sediment movement 3 Motivation Dike breaching Bitterfeld River Elbe Germany August 2002

Mo-i-Rana - September 2002 Dam-break floods and sediment movement 4 Motivation Dike-breaching wave Glashütte Müglitz Germany August 2002

Mo-i-Rana - September 2002 Dam-break floods and sediment movement 5 Motivation Debris flow Weisenstein River Elbe Germany August 2002

Mo-i-Rana - September 2002 Dam-break floods and sediment movement 6 Issues of IMPACT WP4 research Extreme flows  intense erosion and solid transport Intense sediment transport  affects flood-wave prediction –Arrival time –Maximum water level –Morphological changes

Mo-i-Rana - September 2002 Dam-break floods and sediment movement 7 Scope of the research Near-field –Uniform debris flow –Severe transient debris flow Far-field –Intense transport –Bank erosion and geomorphic changes

Mo-i-Rana - September 2002 Dam-break floods and sediment movement 8 Near field : problems to be solved Initiation of movement –Acting forces –Vertical effects –Inertial effects –Sediments bulking Propagation –Intense scouring –Debris-flow front

Mo-i-Rana - September 2002 Dam-break floods and sediment movement 9 Debris flow : research programme Experiments : acting forces (UDT) –Uniform material Months 1-18 –Graded material Months BM UDT ?

Mo-i-Rana - September 2002 Dam-break floods and sediment movement 10 Debris flow : research report Uniform material experiments –Tilting flume (L = 6 m, S 0 = 0° to 23°) –Uniform cylindrical PVC particles Equivalent spherical D = 3.5 mm Density = 1540 kg/m³

Mo-i-Rana - September 2002 Dam-break floods and sediment movement 11 Debris flow : research report Mature debris flow: collisional + frictional Rigid-bed debris flow collisional

Mo-i-Rana - September 2002 Dam-break floods and sediment movement 12 Debris flow : research report Mature debris flow

Mo-i-Rana - September 2002 Dam-break floods and sediment movement 13 Debris flow : research report Mathematical description (collisional) –Normal stress local equilibrium Submerged weight overlying grains Inter-granular collisional contacts (pressure related to granular temperature) –Tangential stress local equilibrium Relation between external and internal tangential stress Effect of added mass

Mo-i-Rana - September 2002 Dam-break floods and sediment movement 14 Debris flow : research report Rigid bed debris flow –Concentration –Velocity profile

Mo-i-Rana - September 2002 Dam-break floods and sediment movement 15 Near-field dam break : programme Experiments: uniform material (UCL) –Same bed levels Months 1-9 –Initial step in bed levels Months 1-9 BM UCL 2 BM UCL 1

Mo-i-Rana - September 2002 Dam-break floods and sediment movement 16 Near-field dam break : research report Experiments: uniform material (UCL) –Same bed levels

Mo-i-Rana - September 2002 Dam-break floods and sediment movement 17 Near-field dam break : programme Mathematical modelling (UCL) –1D model: months 1-6 –2D-V model: months BM UCL 3

Mo-i-Rana - September 2002 Dam-break floods and sediment movement 18 Mathematical modelling (UCL) –1D model: Velocity distribution (Concentration distribution) Near-field dam break : research report pure water mixture u z

Mo-i-Rana - September 2002 Dam-break floods and sediment movement 19 Near-field : research programme Validation of codes (UDT, UCL, Cem) –Uniform debris flow (to be clarified) Months BM UDT ?

Mo-i-Rana - September 2002 Dam-break floods and sediment movement 20 Near-field : research programme Validation of codes (UDT, UCL, Cem) –1D dam-break flow in the near field Months –2D-V dam-break flow Months BM UCL 2 BM UCL 1 BM UCL 3

Mo-i-Rana - September 2002 Dam-break floods and sediment movement 21 Far field : problems to be solved Transition from near-field to far-field Geomorphic changes –Bank erosion and failure Tractive forces applied Failure mechanism –Channel widening –Deposition of material De-bulking Distribution of sediments Formation of secondary dams

Mo-i-Rana - September 2002 Dam-break floods and sediment movement 22 Far field : research programme Laboratory experiments –Dam-break in an initially prismatic valley (UCL) Uniform material Graded material Months BM UCL 4

Mo-i-Rana - September 2002 Dam-break floods and sediment movement 23 Far field : research programme Laboratory experiments –Large-scale model (Châtelet) Prismatic valley Enlargement Months BM Chat

Mo-i-Rana - September 2002 Dam-break floods and sediment movement 24 Far field : research programme Field experiments –Norwegian dam (SG) Geomorphic survey (to be checked) Months 9-12 and BM Norway

Mo-i-Rana - September 2002 Dam-break floods and sediment movement 25 Far field : research programme Numerical modelling –Extension of 2D-H model (UCL) Bank erosion Months ° 37° 85° V bank

Mo-i-Rana - September 2002 Dam-break floods and sediment movement 26 Far field : research programme Validation (UCL, UDT, Cemagref, IST) –Laboratory tests Prismatic valley (UCL) Enlargement (Châtelet) BM UCL 4BM Chat

Mo-i-Rana - September 2002 Dam-break floods and sediment movement 27 Far field : research programme Validation (UCL, UDT, Cemagref, IST) –Field tests WP2 Norwegian dam ? Lake Ha!Ha! Months BM Ha!Ha! BM Norway Brooks and Lawrence 1999

Mo-i-Rana - September 2002 Dam-break floods and sediment movement 28 Benchmark summary Near field Far field BM Ha!Ha! BM Norway BM UCL 4 BM Chat BM UCL 3 BM UCL 2 BM UCL 1 BM UDT ?

Mo-i-Rana - September 2002 Dam-break floods and sediment movement 29 IMPACT - WP4 Dam-break induced floods and sediment movement IMPACT - WP4 Dam-break induced floods and sediment movement Progress report Université catholique de Louvain Yves Zech, Benoit Spinewine and Sandra Soares Frazão