Raw sewage was flushed for five months into a river which feeds into one of Cork’s main reservoirs, supplying drinking water for 40,000 people.
While Uisce Éireann has insisted the quality of the reservoir’s drinking water remained unaffected, it was only after the company was asked for comment by the Irish Examiner that the Environmental Protection Agency (EPA) was informed.
In March of this year, a new 30-apartment development in Glanmire was connected in error to the storm drain on East Cliff Rd, instead of to the adjacent sewage mains. The works had been approved by Uisce Éireann.
Sewage from the Ashbrook apartments was then flushed into the storm drain, flowing into an overflow pipe on the Butlerstown bridge, and down to the water below.
The Butlerstown river feeds into the Glashaboy reservoir, which produces approximately 20 million litres of water per day and serves Glanmire, Glounthane, Carrigtwohill, Little Island, and Cobh, an area with an estimated population of 40,000 people.
Normal water levels in the Butlerstown and Glashaboy rivers masked the sewage, but the recent hot weather caused levels to drop significantly.
As a result, in the past month, the water treatment plant was forced to cease operations three times due to dangerous levels of ammonia caused by sewage.
On August 13, members of the public walking on the new Glanmire greenway noticed the smell and saw clumps of toilet paper and human excrement falling into the river.
The Ashbrook sewage pipe was disconnected from the East Cliff Rd storm drain in the past fortnight, with the sewage being removed periodically by private contractors.
Uisce Éireann said drinking water supplied from the Glashaboy water treatment plant remained safe to drink. “At no time was there any impact on the quality of drinking water supplied to customers or any risk to public health,” a spokesperson said.
Water treatment plants are equipped with continuous monitoring and automated protection systems to safeguard drinking water quality, the spokesperson added.
“As designed, these systems temporarily suspend treatment operations when changes in raw water quality are detected, ensuring the continued protection of drinking water supplies.
“Upon becoming aware of an issue relating to a wastewater connection at a private development which resulted in wastewater entering a local watercourse, corrective works were undertaken, and the matter has since been resolved,” the spokesperson said.
The EPA said it was informed of the incident by Uisce Éireann last Tuesday afternoon, three hours after the Irish Examiner had asked for comment.