The stormwater network, designed for ten-year rainfall events, was overwhelmed by the exceptional precipitation on October 19 and 20. These water volumes, exceeding the design capacity of the structures, may have caused occasional overflows, without necessarily indicating infrastructure failure. Once the rain stops, the networks gradually return to normal operation.
Temporary flooding on roadways is explained by a quantity of water exceeding the network's evacuation capacity, a phenomenon comparable to a sink where the inflow rate is higher than its drainage capacity.
The electromechanical stormwater management systems largely performed their role, despite two isolated incidents: an electrical fault at the Louise-Michel pumping station in Saint-Martin-De-Crau, handled by Enedis and Veolia, and an operational adjustment at the Artisans station (also in Saint-Martin-de-Crau) due to exceptionally high hydraulic levels.
ACCM, in collaboration with the company Guintoli, has undertaken several operations to fully restore the network's capacity: cleaning and clearing hydraulic structures obstructed by debris and branches, reprofiling and dredging ditches to restore their original capacity, and hydro-cleaning buried pipelines to remove accumulated sludge and sediment.
