It will take £14 million and a further three years to begin to restore Lough Leane in Killarney to an acceptable level of water quality, a press conference at the launch of a report on the state of the lake heard yesterday.
The report, based on over 3,000 water samples from the lake's catchment area and two years of scientific fieldwork, identified agriculture as the single largest contributor of phosphate loading to the lake.
Lough Leane's problems came to the surface in 1997 with severe and potentially toxic algal blooms.
The lake is still polluted and is now classed as "moderately eutrophic", the report launched by the Minister of State for the Environment, Mr Dan Wallace, stated.
Kirk McClure Morton and Petit and Co, the consultants who carried out the survey, strongly recommended the introduction of by-laws by Kerry County Council to enforce a code of practice on the storage and management of farmyard waste and slurry.
The loss of nutrients into the lake because of inadequate farmyard facilities and poor slurry disposal practices, as well as over-use of fertiliser, were significant, the consultants said.
Deficiencies of about 70 per cent in the storage capacities of wastes - a level far higher than in other counties - were found on some farms in the Killarney area, Dr Alan Barr of Kirk McClure Morton said. Upgrading storage facilities would cost about £2 million to £3 million.
There are 900 farmers in the catchment area with only 20 per cent participating in the Rural Environmental Protection Scheme. The report recommends that more farmers join REPS.
The Kerry branch of the IFA said it welcomed the report, but said the recommendations would be meaningless without resources to allow farmers to put in place the necessary storage facilities.
However, the bulk of the money needed to address the pollution - over £7 million, with £4 million already invested - will go into the upgrading of waste water treatment plants and collection and disposal facilities. The Killarney waste water treatment plant also requires significant upgrading, the consultants said. Septic tanks in rural areas were a major contributor of phosphates - with almost half of those surveyed failing a percolation test.
It is estimated that agriculture produces 5.8 tonnes or 47 per cent of the phosphate loading seeping into Lough Leane with septic tanks responsible for 1.5 tonnes of MRP (Molybdate Reactive Phosphorus). Forestry contributes a relatively small amount - 3 per cent or 0.7 tonnes of MRP.
The county manager, Mr Martin Nolan, said yesterday the council would be working to implement the report in full. The infrastructure to restore the lake should be in place in three years, he said.