Golfers and spectators attending the European Open at the K Club in Co Kildare next month will be told they are not allowed to fish in the Liffey because of a serious sewage problem that has contaminated the river from Osberstown to Islandbridge.
The event's organisers say that, because of the need to replace one of the four treatment tanks at Osberstown sewage plant near Naas, sewage is being discharged into the river, and the problem will persist for the next three weeks.
The European Open takes place from July 4th to July 9th.
Concern has also been expressed that the sewage could be contaminating the drinking water supplied to hundreds of thousands of homes in Dublin from the Leixlip water-treatment plant.
"I got a phone call yesterday to say that they're replacing a sewage-treatment plant in Osberstown, and we're going to have sewage coming into the river for the next three weeks," said Seán McMenamin, fisheries manager at the K Club.
"We have had sewage-treatment plant problems there for the last six weeks, on and off, and the river has been deplorable. The quality of water here is absolutely dreadful.
"It's at the peak of the season . . . Normally we'd be doing a lot of business because everyone loves to fish the river. All the golfers fish during the European Open. It couldn't have come at a worse time."
Peter Doherty, an angler who lives near the Osberstown plant, said sewage had been visible in the river since early April, but the problem had deteriorated since Tuesday when one of the tanks was closed for maintenance.
"It goes from clear water to tea-colour, and then it goes on down to Leixlip, which is taken out for drinking water for northwest Dublin. This is a public health issue. When you think about it, there's semi-treated sewage going down into drinking water. Work that one out."
He added that there were visible signs of the sewage as far as Islandbridge, which is some 20 miles downstream.
However, the manager at Leixlip water-treatment plant, Paul Smith, said there was no risk to the drinking water supplied by the plant to homes in Dublin.
"Water quality is checked on an ongoing basis, and our analysis shows that the raw water quality is perfect and the quality of water coming out at the end is equally perfect."
Separately, the Eastern Regional Fisheries Board is considering objecting to all new houses in the Osberstown catchment because of its concerns of the recurrent sewage problems in the county.
"We would be considering the option if it looks likely that we're going to have a situation where the river will suffer as a result of the discharge," said the fisheries board's environmental officer Brian Beckett.
Last January Kildare County Council said it would be mid-2007 before facilities were in place to treat the long-standing sewage problem at Osberstown.
Plans for an upgrade of sewage-treatment facilities have been in place since 2000 when a council proposal was put to the Department of Environment under the national water services investment programme.