Cork Lower Harbour Main Drainage Project
The Cork Lower Harbour Main Drainage Project is now complete and wastewater from the agglomerations of Ringaskiddy-Crosshaven-Carrigaline, Ringaskiddy village, Passage-Monkstown and Cobh town no longer discharges untreated to Cork harbour. Instead it is collected and fully treated before its safe discharge to sea.
Irish Water invested €144 million in the Cork Lower Harbour Main Drainage project to address the issue of raw sewage discharge to the harbour and to ensure that wastewater from the above named agglomerations is collected and fully treated before its safe discharge to sea.
In 2015, before work began on the project, the equivalent of 40,000 wheelie bins of raw sewage was discharged every day into Cork Harbour.
Irish Water constructed a new wastewater treatment plant in Shanbally so that by 2017, the equivalent of 20,000 wheelie bins of that raw sewage, was treated every day. We then repaired and extended the sewer network to connect more harbour areas to the plant, Crosshaven and Carrigaline in 2016, Ringaskiddy in 2018, Passage West and Monkstown in 2019.
In 2020, Irish Water completed the Cobh to Monkstown Estuary Crossing. This landmark engineering feat involved drilling under the Lee Estuary, two of the longest horizontal directional drills ever carried out in Ireland. These drilled bores allowed the installation of sewer pipelines at a depth of 60m under the Lee Estuary – creating a vital connection between Cobh and Monkstown.
The final step of the Cork Lower Harbour Main Drainage Project was completed in 2021 with the completion of the Cobh Networks Contract. Raw sewage from Cobh Town is now collected and transferred via the Estuary Crossing to Monsktown and then onwards to Shanbally Wastewater Treatment Plant for treatment before its safe discharge to sea.
More than 20,000 homes and businesses are now connected to the overall scheme and the equivalent of 40,000 wheelie bins of raw sewage no longer discharges daily to the waters of the harbour, but are treated in compliance with the Urban Wastewater Treatment Directive.
The completion of the Cork Lower Harbour Main Drainage Project will support economic growth and development in the area, increasing the potential for tourism and recreational activities and enhancing the fantastic amenity that is Cork Harbour.
The Cork Lower Harbour Main Drainage Project was named Engineering Endeavour of 2021, by Engineers Ireland. See video of the project here.
What is involved?
The Cork Lower Harbour Main Drainage Project consisted of:
- A new Wastewater Treatment Plant (WwTP)
- 15 new pumping stations
- Upgrading of 4 existing pumping stations
- Approximately 30km of new sewers and a drilled crossing under the estuary - Video of the works here.