Pollution
Humain
Environnement
Economique

Warehouse Features:

Established in 2003

Regulatory Regime: Authorization, item 1510

Hydrocarbon storage

Site located in non-flood zone

A stream runs through the entire site via a buried tunnel and then through an open ditch framed by masonry walls and finally by two nozzles (DN 1600) to reach downstream of the site its normal flow.

Heavy precipitation and overflowing streams caused a warehouse to flood. Water levels of 50 cm were observed in the premises. Property damage was estimated at over 3.8 million euros.

Difficulties encountered

Flooding caused several disturbances:

  • loss of electrical power for the entire site over a period of several days (HV transformers out of service);
  • difficulty to circulate in the emergency lanes.

Cause of the flood

The buildings had experienced numerous floods since 2010. Those which occurred in June 2016 were among the worst.

During an on-site visit, the Inspection Authorities for Classified Facilities noted that:

  • the upstream retention to reduce the flow of rainwater into the site’s networks had not been built and the design note justifying its capacity was missing;
  • the operator had not informed the Inspection Authorities of the previous floods on its site, contrary to the requirements of its operating permit;
  • the vegetation and the lack of cleaning of a drainage ditch apparently slowed down the flow of water while reducing the flow cross-section;
  • the cross-section of the conduits in place had to be confirmed, as well as its free-flow cross-section;
  • wooden pallets were stored alongside a warehouse and could have created jams. They could also have represented an additional risk to flood responders.

Measures envisaged

The operator has submitted a set of measures to the administration outlining its plans to protect itself from flooding by installing a third drainage conduit (work costing around 500,000 euros). Updating of the site’s hydraulic study to include elements from the latest flood is also envisaged.