Client: Uisce Éireann
Location: Co. Westmeath, Ireland
Project Value: €73.5m
Description: Upgrade to Athlone’s drainage system to prevent untreated wastewater discharge into the River Shannon and address flooding caused by insufficient sewer capacity, involving extensive infrastructure works within Athlone town and existing pumping station sites.
The works were situated in Athlone town along the River Shannon, involving internal town roads with narrow streets and existing pumping stations at Coosan West and Golden Island. The project targeted 18 storm water overflows and frequent flooding issues due to inadequate sewer capacity.
Infrastructure Works
The project encompassed design and construction of new foul and stormwater pumping stations, decommissioning of old pumping stations, installation of approximately 3 km of new sewer network using tunnelling to minimize traffic disruption, and installation of rising mains and gravity sewers across public and private lands.
Tunnel and Shaft Details
Various tunnelling drives and open-cut works were completed, with HDPE, concrete and PVC pipes ranging in diameter from 400mm to 1800mm. Shaft sizes varied, with diameters from 3.2 to 28 meters and depths up to 21 meters, constructed mostly in-situ.
Design and Construction Challenges
Key challenges included working in compact town areas with narrow streets, managing logistics of large machinery near residences and businesses, dealing with ground conditions like boulders and hazardous landfill requiring onsite water treatment, high water ingress from the River Shannon, and coordination with multiple third parties and flood alleviation projects.
Hazardous Landfill Management
The Golden Island Pumping Station site is a brownfield area previously used for disposal of municipal, industrial, and construction waste. A material management plan and a dig plan were implemented to manage waste and excavations in compliance with national and EU regulations.
Flooding and Water Management
High water levels from the River Shannon affected construction sites, necessitating cofferdams, grouting between sheet piles to prevent water ingress, and temporary flood walls and trench sheet installations.
Traffic Management Measures
To minimize disruption, tunnelling techniques were used for sewer installation, supported by a detailed Traffic Management Plan developed with local authorities. Measures included temporary traffic lights, stop/go systems, road closures, diversions, and maintaining local and emergency access with ongoing community engagement.
Community Liaison and Coordination
The project involved close liaison with businesses, residents, and multiple agencies including Uisce Éireann, Westmeath County Council, ESB, and the Office of Public Works to manage traffic, road closures, and flood alleviation works effectively.