Tetra Tech provided major drainage infrastructure services for the North Dublin section of the Dublin Bay Project to improve stormwater and wastewater management.
Tetra Tech supported Dublin City Council and Fingal County Council on the Dublin Bay Project, the largest of its type in Ireland. This project involved a suite of contracts to eliminate foul flows from the North Dublin catchment to the sea at Howth.
Tetra Tech formed the lead consultant on this project with a review of the existing catchment in the early 1990’s, culminating in the commissioning in 2011 of the final element of the works; the reversal of foul flows from Howth to a new pumping station at Sutton using a variety of open cut and tunnelled techniques.
From there, all flows are pumped forward to Ringsend Waste Water Treatment works, via a 1400mm diameter sub-sea pipeline constructed as part of the works. At 11km long, this pipeline is the largest one of its type in Europe.
Challenge
Tetra Tech were tasked with eliminating foul flows from the North Dublin catchment to the sea at Howth, Co. Dublin. This project presented a number of complex challenges associated with the reversal of foul flows. A number of significant environmental and archaeological constraints existed on the route, which crosses a busy shipping lane in Dublin port. In addition, beach foreshore sections and the close proximity to sensitive bird habitats around Bull Island had to be factored into the design.
Solution
Tetra Tech delivered the following solution for Dublin City Council and Fingal County Council through:
- Design of 5.6km Gravity Sewer and a 2.5km Rising Main ranging in size
- Create drainage area plans or strategic models for foul/combined sewerage network catchments
- Supervise 2,000,000m³ of sand being dredged and safely avoid an uncharted 17th century shipwreck
- Supervise construction of a 1400mm x 11km submarine pipeline in sections using a 300 tonne linear winch
- Design the rehabilitation of 2.6km of sewers within the town centre area using trenchless lining technology
- Constant liaison with the Port Authorities and local interest groups was also managed by Tetra Tech to ensure safety of all vessels during the works
At a glance
Client
Dublin City Council / Fingal County Council
Location
Dublin, Ireland
Services
Construction supervision, contract documentation, design review, landowner and stakeholder liaison, mechanical and engineering design tender assessment, preparation of an EIS, procurement of statutory consents, structural design
The project featured in this article was undertaken by RPS, A Tetra Tech Company and originally published on RPSgroup.com. In March 2026 RPS rebranded to Tetra Tech.