Limerick Tunnel

Limerick Tunnel

Limerick Tunnel

Client: Direct Route (Limerick) Limited

Project: 10km of dual carriageway incorporating 675m of an immersed tube tunnel under the River Shannon.  

Contract Value: €660M

Handover Date: 27th July 2011

Awards: Awarded the Fleming Award in 2008 for ‘Excellence in Geotechnical Design & Construction’.

Protected species management - The Shannon estuary is a Special Area of Conservation (SAC) and is home to a variety of protected species.  The Triangular Club-rush (Schoenoplectus triqueter) is one such species found in several tidal mudflats of the Shannon.  During works this flowering plant was temporarily translocated, under licence from the National Parks and Wildlife Service (NPWS), from 4 works locations to a suitably designed temporary habitat.  This involved careful planning to ensure optimum conditions with respect to the plant life, local tidal conditions, and working times.   The soft muddy and tidal nature of the club-rush habitats necessitated site specific safety precautions.  Marker posts, photographs, and GPS readings were used to record original locations. The temporary habitat took the form of crates within a purpose-built holding tank, with water being pumped in and out to simulate tidal action.  Timed water pumps were set up in line with local tidal conditions.  The club-rush was successfully managed in this manner for over 2 years before being replanted at or near their original locations.

Other protected species managed as part of the works were the Opposite-leaved Pondweed (Groenlandia densa) and the Meadow Barley (Hordeum secalinum); both of which were successfully translocated under NPWS licence.