A BROWN discharge into Skibbereen’s waters sparked an investigation into suspected pollution, which was later found to be algal bloom.

The discolouration of the water was noticed in the River Ilen on Monday July 20th just before 1pm, and a short time later in the Caol Stream running through the town centre.

Cork County Council confirmed that environmental officers carried out investigations at the River Ilen, identifying the discolouration in the water as algal bloom.

‘This occurs naturally in coastal and inland waters and is associated with nutrient in the water and high temperatures. No pollution was evident,’ a council spokesperson said.

An eyewitness, who reported the suspected pollution to Inland Fisheries Ireland (IFI) believed the discolouration to be slurry or raw sewage, tracing its source to a discharge pipe at the junction of Baltimore Road and the town car park. The eyewitness, who asked not to be named, said: ‘The brown colour was very noticeable. I first saw it from Kennedy Bridge on Ilen Street looking into the river. I thought this was agricultural waste coming from somewhere upstream.’

The eyewitness added: ‘At the Caol Stream I saw raw sewage in the water. Wild salmon are currently travelling up our rivers on their annual migration. There is aquaculture at the mouth of the river and in the bay.’

The eyewitness said the brown water would have run into the sea and nearby areas of conservation, Roaring Water Bay and the Loch Hyne/Trallispean area. The River Ilen is 37km long and was for a long time graded as having Quality A water, meaning pollution levels far below the national average. In September 2024, The Southern Star reported high ammonia levels in the river, which weren’t reported to the council for eight days.

A spokesperson for the Environmental Protection Agency (EPA) said latest water monitoring data from 2024 showed that the ecological status of the water in the Ilen Estuary was poor. The rivers flowing into the town were classified as being in good ecological condition.

‘The unsatisfactory conditions in the estuary are being caused by excess nutrients arising from urban waste water overflows, runoff from urban paved areas and agriculture,’ the spokesperson added. The EPA said it had requested Uisce Éireann to investigate the local wastewater infrastructure and network to see if the reported contamination originated from the local treatment plant or network.

‘Uisce Éireann subsequently reported that its Network Operations Team attended the locations and carried out an investigation of the wastewater network. No issues were identified during these inspections. The Skibbereen Wastewater Treatment Plant was also inspected, and no operational issues were found.  Furthermore, no alarms, incidents or overflows were recorded that could be linked to the reported contamination.’

Inland Fisheries Ireland was contacted for comment.