Precautionary notices temporarily banning bathing at Dollymount, Sandymount and Portmarnock beaches in Dublin have been put in place following heavy rainfall this week. The restrictions are likely to remain in place over the weekend.
The incidents arose due to storm water tank overflows at Ringsend wastewater treatment plant resulting in discharges into Dublin bay. The temporary ban was implemented by local authorities in consultation with the HSE.
Irish Water reported a storm water overflow from holding tanks at the Ringsend plant on Wednesday morning after heavy overnight rainfall.
Meanwhile, swimmers confirmed they were told to get out of water at the South Bull Wall on Wednesday night due to deterioration of water quality.
The plant operated in accordance with design and regulations, Irish Water said. “The overflow contained wastewater that was highly diluted with rainwater and had been screened and settled to remove debris – a form of primary treatment. There was also an overflow at the Portmarnock pumping station, again caused by the heavy rainfall.”
The bathing water monitoring site operated by the EPA –beaches.ie – indicated the restriction at Dollymount strand was "due to risk of deterioration in water quality due to discharges breaching limits" – and it would be in place until June 22nd.
The Ringsend plant treats approximately 40 per cent of Ireland’s public wastewater but has been operating at over capacity and not in compliance with national and EU environmental regulations for many years. More than €400 million is being spend on upgrading it and increasing its capacity.
When there is unusually heavy rainfall, the amount of water entering the sewer network can exceed the capacity of the plant and/or network, Irish Water pointed out.
“On such occasions, to prevent the sewer network from backing up and causing flooding of roads and properties, the excess storm water is released to the environment. Irish Water notifies local authorities and the EPA of any incidents or overflow that could impact the receiving waters,” it said.
On Sandymount strand prohibition of bathing was due to risk of deterioration in water quality due to "storm water overflow". Bathing at the adjoining Merrion strand is permanently banned mainly due to discharges from polluted streams nearby.
Meanwhile, bathing restrictions were applied at Seapoint on Thursday due to the risk of deterioration “due to expected heavy rainfall”.
Local authorities are responsible for managing and monitoring bathing waters. Notices are displayed at bathing water locations and on beaches.ie from June to September advising the public on water quality and of any bathing restrictions. “Currently restrictions are in place on a large number of beaches,” Irish Water confirmed.