Hydraulic modelling of the 1999 flood in the lower reach of Agly river

摘要

The high flood that occurred in the southern part of France in November 1999 was one of the highest of the 20th century in the lower reach of Agly river. Although only the catchments of the two tributaries Maury and Verdouble received high rainfalls, the peak discharge reached about 2000 m~3/s, as high as the historical 1940 flood. A 2-D model was updated following the measurements completed immediately after the flood. The calibration was particularly difficult because precise discharges in the main channel and the flood plain remain unknown due to infiltration, drainage network, multiple points of overflow and sediment transport that affected the conveyance of the main channel. Results of calibration and consequences for management of the flood plain are presented. The main concern of proposed works are to avoid the process of breaching of the dikes which was the main cause of damage during the 1999 events.