Case Study

Galway City Water Intake Works

OVERVIEW

In the 1860’s a raw water intake for Galway City’s water supply was constructed on the Terryland River, off the main River Corrib. In 2016, it was determined that a relocated intake, fed directly from the main river, was required to ensure a long term, secure, safe and sustainable water supply for Galway, the fastest growing city in the country.

160 years after the original intake was constructed, this project was implemented to construct a major new intake facility with transfer pipelines and ancillary works, located within the Lough Corrib SAC between the N6 Quincentennial Bridge and the historic Salmon Weir.

terryland waterworks from sea view

Further to abstraction difficulties from the Terryland River during low flow conditions in the River Corrib system during 2014, Galway City Council commissioned Ryan Hanley to identify a new intake location for the Terryland WTP. In 2016 Uisce Éireann commissioned Ryan Hanley to carry out detailed design and secure planning permission for the works that will provide a safe, secure and sustainable supply for the current abstraction of 55 MLD with capacity for the city’s future demand of 90MLD. In 2018 this commission was extended to preparation of Contract Documents and Tender stages and in 2019 Ryan Hanley Stantec were commissioned for the Construction Stage Water Management System of the project.

The project scope included:

  • A new Raw Water Intake structure on the riverbank.
  • 1200mmø, 0.24km long DI transfer main between the Intake and the existing raw water transfer mains including 0.14km long tunnel section under the N6 road in the suburbs of Galway City and open cut excavation under the Terryland River channel.
  • MEICA equipment including Penstocks, Fine Screens with Fish Return and Fish Deterrent Systems. Ancillary works including control building, access road, parkland landscaping and new slipway.

 

Key tasks included in our commission:

  • Planning applications, CPO and liaison with numerous statutory authorities and third parties including Galway City Council, Inland Fisheries Ireland, NPWS, Corrib Navigation Trustees, OPW, NUIG/UG, TII, Galway Rowing Club.
  • Communications; Hydrological and Hydraulic Assessments;
  • Site and Route Selections;
  • Wayleaves and CPO Reports;
  • Demand Projections, Design Flows and Detailed Design;
  • Archaeology, Architectural and Cultural Heritage Impact Screening and Assessments;
  • Environmental and Ecological Surveys and Assessments, including Appropriate Assessment Screening and Natura Impact Statement;
  • Fisheries Protection Measures;
  • Contract Documents, Tender Assessment and Recommendation; – Construction Stage and Cost Management;
terryland water intake works from sea

Delivering major civil engineering works in this urban riparian setting presented a complex project management environment. Significant coordination was needed due to multiple competing constraints and stakeholders. Constraints included: limited available lands, proximity of Lough Corrib SAC, riverside habitats, groundwater and river water levels, built heritage, archaeology, visual impact on protected views, public amenity and riverside access to the public park, river traffic, future development in the locality and water quality protection.

Collaborative engagement with the many stakeholders that could have been impacted ensured their individual and competing interests were addressed in the design of the works and management of construction. From early in our commission Ryan Hanley liaised with Galway City Council, Inland Fisheries Ireland, NPWS, Corrib Navigation Trustees, OPW, NUIG, TII, Galway Rowing Club to identify possible risks to their interests. Early collaboration meant mitigation measures were in-built from the very beginning of the optioneering and design stages, thereby ensuring the most effective outcomes and project success. Some of the key mitigations include:

  • A Water Management System including Attenuation Ponds, Silt Curtain, Silt Fences, Cofferdams and Ongoing Water Monitoring during the construction stage to ensure the risk of discharge of suspended solids into the Aquatic Environment was minimised, avoiding impacting both the SACs protected habitats and the downstream Corrib Fisheries
  • Installation of transfer main by micro-tunnelling beneath the N6 road and Archaeological Zone adjacent to Terryland Castle, avoiding major traffic disruption and potential impact on national monuments and burial grounds.
  • Design of the Intake structure to meet Visual Impact constraints required minimal overground infrastructure
  • Intake headwall cladding designed to replicate existing masonry along the Corrib City complimenting the built heritage of the area.
  • Reinstatement of the public parkland area, tree planting, footpaths and new slipway to ensure no loss of public amenity