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Plan aims to reverse run-off pollution to Our Lady's Island Lake
Nearly 5,000 acres in Co Wexford are likely to be included in an action plan to reverse the pollution of Our Lady's Island Lake.
Taoiseach Micheál Martin has envisaged a cross-departmental, whole-of-government approach to deal with pollution of the lake, where severe degradation is mainly attributed to about 40 years' run-off of excessive nutrients from agriculture.
The 340-hectare lagoonal lake is a few kilometres south of Rosslare, near Carnsore Point. It discharges to the sea via a man-made cut in the sand dunes.
A two-year investigation on behalf of the Environmental Protection Agency found that the lake's poor ecological condition is related to excess nitrogen input. A five to seven-fold reduction in nitrogen and phosphorus inputs will be necessary to try to restore the lake.
According to the investigation report: "Whether such a reduction can be achieved by means such as artificial wetlands, better nutrient management on farms, or watercourse management, remains to be seen". Sediment removal from the lake bed might also be necessary.
"Lady's Island Lake is not the only Irish lagoon in ecological decline, analyses show that most lagoons in agricultural catchments are also eutrophicated," said the report.
Habitat restoration of such lagoons requires reducing the use of imported nitrogen on farmland, measures to retain nutrients on farmland and forestry, removing or capping nutrient-rich bottom sediments, and maintaining or restoring salinity.
A recovery action plan would be likely to focus on the 4,734 acres draining into Lady's Island via 12 feeder streams and other sub-drainage systems.
Of the 72 farmers in this area, 13 have tillage as their primary enterprise (the catchment is known for its early potatoes), 16 dairy, 24 beef, six sheep, and the remaining 13 are equine related or specialise in hay or silage for sale. There are only seven farmers in derogation.
During a recent Oireachtas debate on the state of the lake, Dr Brendan O'Connor, Aquafact International Services Ltd, co-author of the report for the EPA, said: "Farmers are substantially compliant with the current legislation". But there would have to be changes in the rules, "or we will have to help farmers to farm in a slightly different way".
He suggested: "We put in buffer zones that are bigger than required. We have buffer zones of 10m instead of 3m. We actively manage the buffer zones, rather than just putting in a buffer and walking away."
Other remedial techniques on the farms are likely to include fencing of watercourses and replacing cattle drinking points with water troughs, buffer zones at drainage outlets, hedgerow and woodland planting, sediment traps, settlement ponds, arable grass margins, farm roadway works, soil sampling and Nutrient Management Plans.
However, some have suggested more radical measures. Dr Cilian Roden of Aquafact International Services told the Oireachtas debate Ireland should reduce food production, or do something about efficiency, because the more food exported, the more nitrogen is put into our environment. He said 70% of nitrogen, which costs a lot of money to import, is being flushed into the lakes.
Dr O'Connor said it could take up to 20 years to restore the lake, even if agricultural nitrate pollution ceases, and the lake bed is dredged.
Farm inspections
Since 2018, Wexford County Council conducted 30 farm inspections under planning application requirements, Good Agricultural Practices audits, and in response to environment complaints. Minor non-compliances were found and cross-reported to the Department of Agriculture for sanction with single farm payment penalties.
Poorly maintained septic tanks may also have contributed to the lake pollution. A further 90 inspections of septic tanks were conducted between 2018 and 2022, of which 63 failed inspection. There were 21 systems directly discharging to surface waters. Six septic tank failure cases remain open, and are being actioned by the Council.
It has been calculated that total annual inputs to the lake from all sources (principally agriculture) amount to 60 tonnes of nitrogen and 1.8 tonnes of phosphorus.
Less than 1% of the nitrogen arises from the small wastewater treatment plant serving the village of Lady's Island and its population of 182. The council has twice upgraded the plant.
When the council sampled all 12 feeder streams and a discharge point southwest of the lake last April, 11 of the 13 samples exceeded nitrate limits for surface waters, and eight of 13 exceeded phosphate limits.
An anti-pollution scheme is likely to cost about €2.25m (excluding dredging of the lakebed, which might be necessary). In addition, a proposed pipeline from the lake to the sea is estimated to cost €2.5m. Bringing local wastewater for treatment elsewhere would cost €5-6m.
Special Area of Conservation
The flora and fauna of the lagoon bed died when decay of algal biomass deoxygenated sediments. Dr Brendan O'Connor said the lake now smells of hydrogen sulfide, and unsightly algae washes up on the lakeshore.
It is designated as a Special Area of Conservation for lagoon and other habitats, and as a Special Protection Area for birds, including four species of terns that nest on islands in the lake.
Nature conservation is carried out by the National Parks and Wildlife Service, with a high degree of support and co-operation from landowners and the local community in tasks such as daily wardening of the internationally important tern colonies, and cutting a drainage channel through the seaward barrier each spring, to drop water levels in time for the nesting season.
There is also a project to save Ireland and the UK's last remaining cottonweed, which is found on the seaward barrier of the lagoon. The NPWS has also commissioned a survey of Foxtail Stonewort and Bearded Stonewort, two rare lagoon plants.
