The report of the Environmental Protection Agency – EPA – Water Quality in Ireland 1995-1997, indicated a marked improvement in the water quality in Lough Derg and classified the lake as moderately eutrophic. It is understood that more recent data indicate a continuing improvement in Lough Derg.
Water quality in Lough Derg is being comprehensively addressed in the context of the Lough Derg and Lough Ree catchment water quality monitoring and management project, which is administered jointly by Clare County Council and Roscommon County Council. This project is being undertaken in conjunction with a major investment programme which will upgrade the sewerage networks and waste water treatment plants at 17 of the main population centres within the catchment. Over £48 million has been allocated to the schemes, with 85% financial support provided by the EU Cohesion Fund, and substantial progress is being made in their delivery.
The Lough Derg and Lough Ree catchment water quality monitoring and management project aims at establishing a monitoring and management system in the Lough Derg and Lough Ree catchment. The project takes account of the EPA report, Quantification of Phosphorus Loss from Soil to Water, which was published in April 2000. A final project report is expected early in 2001.