The project included the main tunnel crossing of the River Shannon, a Special Area of Conservation (SAC) designated under the EU Habitats Directive. The southern approach to the tunnel passed through Bunlicky Lake, a Natural Heritage Area (NHA). In addition the scheme, traversed through the Lower Shannon Special Protection Area including Cratloe, Meelick and Ballinacurra Creeks (SPA) designated under the EU Birds Directive. The tunnel is an immersed tube tunnel measuring 675m in length. The tube consists of two bores, for Southbound and Northbound traffic. Five tunnel units were cast, floated out and sunk into a pre-dredged channel. The tunnel is completed by cut and covers sections at each end and approach ramps.