Northern Ireland sewers get a makeover

Feb. 18, 2009
A major part of Northern Ireland Water's Londonderry Drainage Area Plan (LDAP) has now been completed ahead of schedule. The Victoria Market Wastewater Pumping Station is a key component...

January 2009 -- A major part of Northern Ireland Water's (NI Water) £21.6m Londonderry Drainage Area Plan (LDAP), which was project managed by Faber Maunsell | AECOM and Halcrow, has now been completed ahead of schedule.

The £3.9m Victoria Market Wastewater Pumping Station is a key component of the ongoing infrastructure improvements in Londonderry. The project comprised the construction of a new sewage pumping station, a storm flow meter chamber, new control building and twin 1200mm diameter outfall pipes and an associated outfall chamber.

The new pumping station at Victoria Market will enhance the existing infrastructure in the area and will help alleviate flooding in the city.

David McCune, Regional Director at Faber Maunsell's Belfast office said: "This project presented the team with many difficult challenges due to the busy city center location. The only suitable location for the new pumping station was below ground in Victoria Market car park.

With the site heavily congested with underground services, the presence of the existing pumping station (which had to remain operational throughout the project) and the close proximity to local businesses, careful planning and execution was required during the construction stage."

A key challenge was groundwater in the area due to the close proximity of the tidally influenced River Foyle. The cofferdam required for the construction of the main pumping station element was excavated to a depth of 7.0m. In order to deal with the ground water a system of perimeter dewatering wells was installed to lower the water to a safe level.

A key component of this project involved the installation of the large diameter storm outfall pipes and associated outfall chamber. This work involved crossing the busy Harbour Square Roundabout and had the potential to cause serious disruption to motorists. NI Water in partnership with Shearwater Consortium and Faber Maunsell | AECOM managed to reduce disruption to traffic by developing and implementing a two phased traffic management system which permitted undertaking the proposed work in two halves.

The first phase involved the installation of the outfall chamber and one half of the outfall pipework. Traffic was diverted to the west side of the roundabout and a one way system was employed. Upon completion of the first phase the traffic management was switched over to close the West side of the roundabout and a similar one way system was implemented.

The project had a very tight program and NI Water and the project team considered it paramount, especially in the current financial climate, that disruption to local businesses and shoppers was minimized as much as possible. NI Water funded a temporary car park close to Victoria Market in order to keep any inconvenience to a minimum. Through careful planning and added site resources the project team was able to complete the project three weeks ahead of schedule and within budget.

Nigel McKee, NI Water Project Manager said: "I would like to take this opportunity to thank all of the team involved in this project -- our contractors Shearwater, Halcrow and Faber Maunsell. The investment at Victoria Market is part of NI Water's commitment to providing a modern and effective sewerage system and is just one example of the many projects being undertaken to deliver a 21st century infrastructure to Northern Ireland."

Londonderry is the second largest city in Northern Ireland and is located approximately 70 miles from Belfast. The city is bisected by the River Foyle which flows into Lough Foyle to the north east of the catchment. The catchment covers an area approximately 2,600 hectares and is characterized by areas of high ground which slope steeply down to the flood plain of the River Foyle.

The approximate residential population is 93,000. The majority of properties within the catchment area are currently served by a combined drainage system although most of the road network is served by a separate storm system. The future strategy is for treatment to be centralized at Culmore with the existing works at Drumhoe due for decommissioning.

The overall Londonderry Drainage Area Plan is expected to be complete in Summer 2010.

Faber Maunsell | AECOM is an award-winning, international consultancy specializing in buildings, transportation and environmental services.