Cork's Lower Harbour Main Drainage Scheme is designed to address the unacceptable legacy practices of the past, while delivering modern, high-quality wastewater infrastructure that will benefit future generations, write Catherine Sheridan and Déaglán Healy
Civil

When you read headlines highlighting that raw sewage continues to flow into our waters at 43 urban areas across Ireland (The Irish Times, November 23, 2016), the scale of the problem facing Irish Water is clear.

For decades, untreated wastewater has been discharged into our rivers and seas at towns and villages from Howth in Dublin to Kilmore Quay in Wexford and Ballyvaughan in Co Clare. This is a nationwide problem and Irish Water is committed to addressing it and ensuring that these 43 untreated agglomerations are receiving treatment by 2021.

New treatment plants completed


New treatment plants have recently been completed at St Johnson, Donegal, and Kinvara in Galway, with Rush, Youghal, Belmullet, Killybegs and Bundoran due for completion early this year.

Three of these agglomerations are located in the Cork Lower Harbour area, where, until December 2016, the volume of raw sewage discharged into the sea was the equivalent of 40,000 wheelie bins daily.

The commissioning of the new wastewater treatment plant at Shanbally at the end of 2016 saw the volume of untreated sewage discharging into the harbour reduced by half.

€135m investment


The Cork Lower Harbour Main Drainage Scheme marks a €135 million investment, in a new state-of-the-art wastewater treatment plant at Shanbally, 14 new pumping stations, 30km of new sewers, repair work on existing sewers and a drilled crossing under the estuary.

It forms part of Irish Water’s overall business plan and marks a significant investment in critical infrastructure in Cork supporting future growth and economic development. It will also ensure that Ireland achieves compliance with the European Union’s Urban Waste Water Treatment Directive, helping avoid substantial financial penalties.

The project is being developed in a number of phases:

1. Wastewater treatment plant at Shanbally (B)
2. Work on the sewer network on the south side of the harbour (A & C)
3. Work on the sewer network on the north side of the harbour (D)
4. Completion of a drilled crossing under the estuary

Cork County Council had progressed elements of the project in conjunction with consultant engineers Nicholas O’Dwyer Ltd, prior to Irish Water assuming responsibility for water services in January 2014, and continue to work in close partnership with Irish Water to deliver the project.

New solution to connection of northern network


Cork County Council secured overall planning permission from An Bord Pleanála in 2012. However in 2013 they began a detailed design review and identified a new solution to the connection of the northern network, involving a drilled estuary crossing under the harbour, which was found to be feasible due to technological advances since the original grant of planning.

This also had the benefit of removing the need to close the main road and railway line into Cobh for a six month period, which would have isolated the community, effectively turning it into an island for the duration of the works.

Irish Water developed a 146b application to An Bord Pleanála and successfully secured planning permission for a revised proposal to include the estuary crossing.

Fully operational wastewater treatment plant within 18 months


Construction work officially started in 2015 and a major key milestone has already been achieved with the completion of the wastewater treatment plant at Shanbally in December 2016. Within 18 months, it went from a greenfield site to a fully operational wastewater treatment plant.

This meant that 50 per cent of the problem has already been addressed, with the wastewater from 10,000 homes across Crosshaven, Carrigaline and Shanbally now diverting to the new plant. A noteworthy feature of the Shanbally plant is the use of innovative aerobic granular sludge technology.

Also used in Carrigtwohill and Clonakilty, Co Cork, this technology requires less energy and chemicals to operate and occupies a smaller footprint than conventional treatment technology; enabling us to deliver more environmentally friendly and economically sustainable solutions than traditional treatment options.

As the project has progressed, Irish Water has secured six Section 50 applications, two Strategic Infrastructure applications, two compulsory purchase orders and three foreshore license applications.

Work under way on pipelines and pumping stations


The 2015 CPO was Irish Water’s first in conjunction with a strategic infrastructure development. Work is now under way on the pipelines and pumping stations on the south side of the harbour and Irish water plan to progress work on the crossing and Cobh construction works in 2018. The project is on schedule to be substantially complete by 2020.

The sequencing of the works and the various requirements of each phase required a multifaceted approach to contract management. The novation of the original employer’s representative contract for the project from Cork County Council to Irish Water, via the Government Conditions of Contract, was just the first of five different forms of contract. The delivery of the wastewater treatment plant was achieved through a FIDIC gold book contract.

The south side networks contracts were awarded with an Irish Water developed Major Civil Engineering form of contract, leveraging from the experience of our gas networks business in delivering similar pipeline infrastructure.

New Engineering Contract model being utilised for estuary crossing


The tender for the delivery of new pumping stations and a new wastewater network in Cobh is progressing under an Irish Water Design Build Form of Contract. Finally, the New Engineering Contract (NEC) model is being utilised for the estuary crossing as the most suitable form of contract for the specialised area of drilling and estuary crossings.

The various contract models bring an additional area of complexity to project management, but equally the negotiated procedure under the utility directive allows for a clarification process to ensure all tendering entities have a clear understanding of Irish Water’s requirements.

Irish Water works closely with local communities across the lower harbour to raise awareness of the importance of this investment in water quality and to engage with stakeholders in relation to planned work at all stages of the project.

Irish Water has hosted 75 community engagement events for residents and businesses and currently operates a text message service to keep communities updated weekly on road closures and planned works in all affected areas.

Public engagement


A range of communications collateral including project brochures, newsletters, project videos, project storyboards, advertisements, posters placed locally and notices in community and parish newsletters, have all been developed to support public engagement.

The role of a full time Community Liaison Officer (CLO), visible in the community and working closely with the Resident Engineering team and with locals directly impacted by the works, has been a very positive feature of the work to date.

Community Engagement is currently undertaken by a CLO appointed by the contractor to manage communications as work continues on development of the pipeline network in towns such as Monkstown, Carrigaline and Passage West. At each stage the project teams have looked for innovative ways to engage and reach as wide an audience as possible.

Leading and lagging metrics


Safety is at the heart of everything that Irish Water does and no job is so important that it can’t be done safely. In carrying out the construction works, the associated contracts contain Key Performance Indicators (KPIs) which reward safety excellence and penalise poor performance. Both leading and lagging metrics are monitored and the IW RE site team includes a full time HSQE Supervisor.

Overall, while the Cork Lower Harbour Main Drainage Scheme is designed to address the unacceptable legacy practices of the past, it will ultimately deliver modern, high-quality wastewater infrastructure that will benefit generations to come.

It is designed to accommodate future growth across the region and will support new industry locating in Cork as well as planned housing developments. There are many challenges in delivering this complex project, but it is one that the Irish Water take pride in delivering for the people of Cork and beyond.

Authors: Déaglán Healy, project manager, Major Projects, Ervia Group. Civil & Mechanical Engineer with more than 25 years’ experience in the planning, design and construction of utility pipeline projects. Currently responsible for the delivery of the Cork Lower Harbour Main Drainage Project.
Catherine Sheridan B.E MSc. CEng MIEI PMP has 18 years’ experience in the planning and delivery of water and wastewater projects including community engagement and communications. Having worked with Irish Water and Major Projects, her current role with Ervia is as brand communications technical adviser.

http://www.engineersjournal.ie/wp-content/uploads/2018/02/cork-1024x908.pnghttp://www.engineersjournal.ie/wp-content/uploads/2018/02/cork-300x300.pngDavid O'RiordanCivilMissedCork County Council,Irish Water,wastewater
When you read headlines highlighting that raw sewage continues to flow into our waters at 43 urban areas across Ireland (The Irish Times, November 23, 2016), the scale of the problem facing Irish Water is clear. For decades, untreated wastewater has been discharged into our rivers and seas at towns...