Northern Ireland Wastewater Gains CEEQUAL Excellent

Situated on the coastline of the Irish Sea and overlooked by the majestic Mourne Mountains, this upgrade represented a major investment by NI Water to improve the standard of discharge and quality of bathing waters in this popular seaside town.

Challenged with constructing a complex build, extending 2,000m2 into the Irish Sea, we would design and create a completely watertight area to facilitate construction and furthermore protect the surrounding Murlough Area of Outstanding Natural Beauty and Mourne Coast Area of Special Scientific Interest.

The project involved creating a cofferdam: initially a stone bund was formed within a geotextile envelope, surrounded by rock armour to protect the works from the Irish Sea’s winter gales, flash floods and high tides. Sheet piled wall was driven through bund into bedrock to cut off water flow. A battery of pumps ensured that the tidal groundwater was forwarded to silt traps and settlement lagoon for filtering before returning to the sea.

Aspirations for a green roof saw consultation with local heritage and conservation groups to deliver a herb-rich maritime grassland, rich in biodiversity, spanning the entire roof area. This low maintenance native vegetation continues to provide a natural habitat for birds and insects. Safe-guarding this legacy maintenance contract was extended to 5-7 years. Wildlife habitat further enhanced through construction of bird ledges for Kittiwakes, shelters for Guillemots, otter holt, bat box and insect habitat.

Other key achievements saw all excavated material including excavated rock and breakwater rock armour reused in works or exported to other construction projects. Further opportunities to improve water quality in the area saw significant additional upgrade works to the contract period.

People and communities
Partnership links were established with key interest groups early in the contract including Mourne Trust Volunteers, Wild sea swimmers group, Harbour Regeneration Group.

On a voluntary basis the site was registered with the Considerate Constructors Scheme, providing the public with the opportunity to assess how we delivered the works within the neighbourhood. Project received National Bronze Award. As a Company Partner within the Scheme the site also received a National Silver Award, with “Excellent” scores for appearance and maintaining good relations with the local community.

Other achievements include an ICE Northern Ireland Sustainability Award and Finalists in CEF Construction Excellence Awards.

Ecology and biodiversity
Aspirations from the Project Team for a green roof saw consultation with local heritage and conservation groups to deliver a herb-rich maritime grassland, spanning the entire roof area.

Working with local landscape experts from the County Down area and members of the Mourne Heritage Trust (MHT), the team devised a low-maintenance landscape plan that would be rich in biodiversity.

Using a special process known as hydroseeding, the top of the new 50m-long concrete structure was sown out with a special mix of indigenous coastal seeds to provide a low maintenance native vegetation green area, which not only offers a more attractive view for the overlooking properties, but which also provides a natural habitat for local birds and insects.

Safe-guarding this legacy maintenance contract was extended to 5-7 years.

Habitat for seabirds and local wildlife further enhanced through construction of bird ledges for Kittiwakes on the seaward side of the building, bird shelters for Guillomots resourcefully constructed from recycled drainage pipes & manholes within new rock armour, otter holt, bat box and insect habitat.

The water environment
Challenged with constructing a complex build, extending 2,000m2 into the Irish Sea, we would design and create a completely watertight area to facilitate construction and furthermore protect the surrounding Murlough Area of Outstanding Natural Beauty and Mourne Coast Area of Special Scientific Interest.

Creating a cofferdam, initially a 250m long stone bund was formed within a geotextile envelope, surrounded by 13,000 t’s of rock armour to protect the works from the Irish Sea’s winter gales, flash floods and high tides. 210 lm sheet piled wall was driven 14m through bund into bedrock to cut off water flow. A battery of pumps ensured that the tidal groundwater was forwarded to silt traps and settlement lagoon for filtering before returning to the sea.

Physical resources use and management
Other key achievements saw all excavated material including 2,000 tonnes of excavated rock and 13,000 tonnes breakwater rock armour reused in works or exported to other construction projects.

Accepting the award on behalf of the project team, Kieran Grant, NI Water’s ProjectManager for the scheme said: “This £10m project represents one of the most complex wastewater facility upgrades to be undertaken for NI Water in recent years. Located on the County Down coast, in one of NI’s top seaside resorts, the Newcastle Wastewater Treatment Works Project presented NI Water and its contractor, Dawson-Wam Ovivo JV with numerous civil engineering, environmental and aesthetic challenges, all of which were overcome on a highly successful project fully embraced by client and contractor alike. We are delighted to receive this prestigious award which is a fitting tribute to the efforts of the entire design and construction team.”