Construction: Scott Wilson & Ferguson McIlveen and Whitemountain Quarries
Client and Designers: Northern Ireland Roads Service
Following the Good Friday Agreement the Chancellor announced a package of new road schemes for Northern Ireland. As part of the implementation of this package, the Department for Regional Development – Roads Service, appointed Scott Wilson (Scotland) Ltd. / Ferguson McIlveen LLP in Joint Venture as Consultants for the Newtownstewart Bypass at the end of 1998.
Working closely with Roads Service (Western Division), the team progressed the scheme through the statutory procedures in accordance with the primary legislation for Trunk Road schemes in Northern Ireland, The Roads (NI) Order. This has included the production and publication of an Environmental Statement, Direction Order and Vesting Order which were all subject to Statutory and Public consultation.
The bypass crosses the scenic and environmentally sensitive Strule River valley and significant measures were adopted to integrate the road into the landscape and to mitigate environmental impacts both during construction and when the road is in service. With a fish farm a short distance downstream and as an important fishing river in its own right, protection of water quality in the Strule was a major factor from the design viewpoint.
The Roads Service procured the works through a Design & Build Contract, awarded to Whitemountain Quarries and their designers, Parkman, in June 2001.
The £7 million project involved 2.6km of single carriageway trunk road bypass, some 900m of side roads, two composite bridges over the River Strule, construction of a reinforced concrete box culvert beneath the new bypass to to form a grade separated junction, and construction of 200m of retaining walls and a reinforced concrete pedestrian underpass. The scheme also incoporated the innovative use of a Sustainable Urban Drainage System (SUDS), which has no kerbs, an open stone filter with perforated pipe at its base being installed along both sides of the road. Surface water is led from these drains to five detention basins. These are planted with reeds which can neutralise contaminants in normal flows. Water from the basins is discharged to the river via penstocks which can be closed in the event of a serious spillage.
The Newtownstewart bypass not only features many civil engineering techniques, but was also the first contract in Northern Ireland to be carried out with an integrated management system for quality, environmental and safety standards.
The bypass opened in December 2003, two months ahead of schedule.