Haulbowline east tip remediation

Ireland’s only steelworks operated on Haulbowline Island in Cork Harbour from 1939 to 2001, leaving behind significant waste that presented environmental challenges. Spearheaded by Cork County Council on behalf of the Department of Agriculture, Food, and the Marine, the project aimed to remediate the island often referred to as “East Tip”, a site with 650,000m³ of industrial waste including steel slag and hazardous asbestos. This initiative aimed to transform the area into a flexible public park while ensuring no contamination or environmental impacts on surrounding communities, marine life and ecosystems, meeting stringent environmental waste directives.

The contractor, PJ Hegarty & Sons, appointed Ayesa to provide design consultancy services for the redevelopment and remediation of East Tip Haulbowline Island. Our responsibilities included the temporary works and detailed design and construction support for approximately 1 km of a coastal revetment structure, which would serve as a coastal defence for the remediated public amenity park. The remediation works posed significant technical and environmental risks, in addition to strict conditions set out by the EPA Waste Licence.

Site investigations identified evidence of asbestos and other hazardous waste within the slag deposits. The ground conditions, featuring soft marine alluvium below concrete-like slag deposits, added complexity to the project. These conditions had to be managed to ensure the constructability of the perimeter structure on the foreshore. The remediation included installing a perimeter-engineered structure that lowered groundwater to prevent waste seepage into Cork Harbour. The site’s 830-metre shoreline was re-formed with 35,000 tons of rock armour and 45,000m³ of subsoil.

To protect park users from exposure to contaminants and limit the infiltration of surface water into the waste and groundwater, an engineered capping system was provided. More than 350 tonnes of steel and existing structures were removed, and the site was regraded and capped with a polyethene membrane, a geocomposite drainage layer, and soil. Associated site works included the provision of drainage, walkways, seating, car parking, toilet facilities, an access road, a new sports pitch, and landscaped wetlands and wildflower meadows.

The project faced several complex challenges due to the nature of the waste material, the existing landform, and the marine location within the foreshore tidal zone. Reprofiling was necessary because the irregular ground caused by stockpiled materials needed to be reshaped into a stable landform that met environmental regulations.

Managing the ground conditions, which included soft marine alluvium below concrete-like slag deposits, was crucial to ensure the constructability of the perimeter structure on the foreshore. Ayesa delivered an innovative design solution that addressed these remediation objectives and managed significant contractual risks. Additionally, Ayesa designed silt curtains and anchors to limit the risk of contamination in Cork Harbour, addressing both environmental and technical complexities.

This transformation revitalised the area and earned accolades for its innovative approach to converting an industrial wasteland into a vibrant community asset. The site was developed into a public recreational area with playing pitches, walking/jogging circuits, picnic areas, viewing points, and a car park. This project has been recognised with multiple awards.

2021: Engineering Project of the Year.

2019: Local Authority Engineering Initiative Award.

2020: Irish Construction Excellence Award.

2020: Association of Consulting Engineers of Ireland (ACEI) Engineering Excellence Award.