Water of Luce Dalnigap Channel Realignment

Tender description

GRT has secured funding from NatureScot’s Nature Restoration Fund for capital works at a site along the Luce catchment in South West Scotland (Fig. 1), at Dalnigap, New Luce, Dumfries and Galloway, DG8 0AZ, NX 13494 71764. In the late 1800’s a channel was cut through an area of raised peatland at this site, through which the Main Water of Luce was diverted. Detailed designs and engineering specifications have been produced to now return the river channel back to its original natural course. This involves excavating parts of the old channel (850m long), blocking off the artificial channel and protecting the eroding peatland face. This project will realign a 550m section of the main stem of the Water of Luce, providing significant ecological and hydrological benefits, extending it into an 850m multi-channelled river corridor with wider connections to the historic floodplain and surrounding peatland. GFT is seeking a suitable qualified and experienced contractor to conduct the capital works at this site. Lot 1: The appointed contractor would conduct the necessary capital works at the site, following the design and construction specifications that can be found within the detailed designs (see attached). One alteration to these designs is that all angular rock is now to be sourced from material won onsite, details of this change can be found within the construction update document attached. The methodology will include: - Site plotting; - Excavation of the infilled historic upstream and downstream channels across the flood plain; - Excavation of the preexisting upstream channel and downstream channel to the excavated channels; - Construction of two instream plugs across the preexisting channel to sufficiently divert flows to the excavated channels; - Excavation of a swale feature between the two plugs to facilitate connections during high flows; - Purchase, transportion and installation of coir matting across the two plug features; - Transportation and installation of several opposite-bank large instream wood structures across the straightened section of downstream works area; - Assist in revegetation of the site through purchasing and transporting of appropriate seed mixes across the works area. The methods used to get to this point will follow the design and engineering specifications produced within the detailed designs and would be conducted under the supervision of the detailed designers, hydromorphologists and GRT. GRT will also be conducting a fish rescue during the stage in which the instream plugs and reconnections will be constructed.