Client: Jons Civil Engineering Limited
DBFL were part of the Design Build Team with Jons Civil Engineering, delivering this key piece of infrastructure, providing civil, structural, transportation and PSDP design services
This phase of the historical Ulster Canal refurbishment project involves the detailed design of nearly 1km of new canal, a new 42-berth marina at Clones, Siphon of River Lacky and Aqueduct over the River Lacky, 2 new access bridges, restoration of an existing bridge, plus associated works, as well as approx. 1.5km of new walking and cycling trails along the canal between Clones and Clonfad.
The Ulster Canal, which runs through counties Armagh, Fermanagh, Tyrone, Cavan and Monaghan, was built in the 19th century but was abandoned in the early 1930s.
The Phase 2 Works included site clearance and enabling works; a new recreational marina with slipway; 600m of new canal waterway; 1.5km of new trails for walking/cycling; new public amenity area with services and parking; Sustainable Urban Drainage (SuDS); two new vehicle bridges over the new canal; construction of Clonfad Aqueduct to facilitate the new canal passing over the River Lacky; refurbishment of an existing masonry arch bridge; multiple pump stations including a 40l/s Water Recirculation pump station and rising main; automated canal level control through the use of valves to control canal flow.
There were numerous constraints and complexities involved with the design and construction of Ulster Canal Restoration Phase 2.
The main constraint was the extremely poor and varying ground conditions with peats and soft alluviums extending up to 14m in depth surrounded by steep topography. Various options were considered with a combination between dig and replace and piled solutions utilised for formation below concrete structures. Detailed pile analysis was carried out considering the various marina wall loading scenarios.
Further constraints included the diversion of an existing trunk sewer which was in bad repair due to the poor ground conditions including assessment of foul sewer catchment and risk of surcharging/flooding; diversion of existing river to construct siphon and aqueduct required to facilitate Canal passing over existing river; culverting existing watercourse into a 1500mm culvert and attaining Section 50 required following catchment analysis; slope stability analysis of steep cut slopes.
The re-use of site won clays combined with geosynthetic clay liner prevented water loss from the canal. This initiative replaced the previous Waterways Ireland standard of imported puddle clay and a HDPE liner. This reduced the amount of both exported and imported materials.
Project Director
