Areas sensitive to eutrophication in the department of Orne before 1999.

Sensitive areas require more stringent treatment of urban waste water. They include bodies of water which are significant at basin level which are particularly sensitive to pollution, in particular those which are subject to eutrophication and in which the discharges of phosphorus, nitrogen or these two substances must, if they cause this imbalance, be reduced (Article 6 of Decree No 94-469).