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Logistics challenge on the Island of Groix

In the Morbihan region of Brittany, France, teams from Spac, a Colas subsidiary specializing in water and energy transport, are renewing the drinking water pipes on the Island of Groix. Projects have been ongoing to gradually replace equipment that has become obsolete. In particular, Spac has completed the connection of the island's new water treatment plant to the Port-Melin dam and to boreholes. 

The project required the laying of 2,400 m of new pipes, which had to be connected to the existing network, the final removal of the valve sets, so that the plant would be supplied only by the new pipes. Island construction projects often require excellent upstream management of material supplies, a key component to keep work running smoothly.

No interruption of water supply

Similarly, the work to connect the network to houses required the total replacement of the existing pipes, which were cracked and made of asbestos, with new cast iron pipes. 35 connections were installed to serve each house. All of this was done without cutting off the water supply: the switchover to the new network was made after sanitation tests had been carried out. 300 tons of aggregates were transported from the mainland because the island has no quarries. 

Recovering construction waste

Conversely, managing construction waste is also a challenge. To avoid having to store excavated material on the island or transport it to the mainland, Spac's teams decided to treat it on site and transform it into quality backfill. Once the water pipe had been laid, the cut was mixed with cement and added as backfill for the trenches. On-site waste recovery is both economical and practical, and helps limit the carbon footprint of construction projects.