The most polluted stretch of river in the State could become one of the top salmon fishing waters in Western Europe under an ambitious environmental clean-up plan.
The 7-kilometre stretch of the Avoca river has been severely damaged by acidic discharges from nearby disused mines.
Highly acidic effluent, which is still being discharged from the mine, has caused 38 fish kills in the Avoca area in the past 18 months alone, rendering the river uninhabitable. Most of the fish kills have involved salmon and sea trout.
The effluent is the result of rainwater reacting with metals and sulphur in more than 50 km of shafts underground.
Located in the picturesque Vale of Avoca, the river and nearby village of Avoca have been a popular tourist attraction for decades.
The area is also well known due to the popularity of the BBC drama, Ballykissangel, which was set there.
Despite the rural idyll portrayed in the programme, the Avoca river has been classed by the Environmental Protection Agency as the most polluted stretch of river in Ireland.
A study by fisheries experts in 2001 and 2002 also found there was effectively no fish living in the river between Avoca and Arklow.
The leachate from the mines flows out into the river from two adits, or mine drains, built over 100 years ago to take the water from the shafts which criss-cross the 60-hectare site of the mines, which are located on either side of the river.
However, now the Eastern Regional Fisheries Board (ERFB) has put forward a €4 million plan to clean up the river, and turn it into one of the cleanest in Ireland.
A recent study by scientists from the University of Newcastle has recommended the construction of two treatment plants at the adits. The effluent would be treated to remove the high metal content and reduce the acid levels.
"It has the potential to become one of the top five salmon fisheries in the country," according to Ms Josie Mahon, an inspector of the ERFB, who is co-ordinating the plans.
She acknowledges the cost of the clean-up is significant, but believes the economic benefits will outweigh this.
"We've found salmon and sea trout upriver as far as Glendalough, and an economic study by Indecon suggests that angling tourism could bring in €750,000 a year into the local economy."
The plan has also received support from Wicklow County Council and Government agencies, and the ERFB is now seeking funding from the Government and the European Union for a pilot project.
Under European water quality legislation, the Government is required to take action to clean up polluted rivers such as the Avoca over the next few years.
"The Water Framework Directive is there, so we are up against it to get this done," she said.
The mines, which were worked on an industrial scale for 200 years, closed in 1982. At its height in the late 19th century, over 2,000 people were employed there. Over 1 million cubic metres of mine spoil have been left behind. It is believed that the Avoca became one of the first rivers in Ireland to become polluted by industrial activity.
Arklow, which is 10 miles down river, had what were considered to be the best oyster beds in the British Isles in the mid-19th century; these became contaminated with copper. The University of Newcastle study has suggested these beds could be re-established once the Avoca is restored.