Tidal and In-River Works

Elterwater Remediation Scheme, Cumbria

Working for the South Cumbria Rivers Trust, Grant Ltd took 3 months to complete this river water diversion scheme. A blister coffer dam was needed to dry out a bankside working area to construct a screened intake, and then 350m of gradient fall pipe to an outfall into Elterwater. Encountering hard rock, swampy peat, and the wettest weather conditions in living memory, Grant Ltd workforce braved floods and major road diversions to get to work and were still able to complete on time.

Palnackie WwTW, By Dalbeattie, Dumfries and Galloway

Client Scottish Water wished to install two new Condor sewerage treatment tanks to serve the small coastal port of Palnackie, near Kippford. The installation next to the tidal reaches of the Urr Water, required a supported coffer dam and excavations to below low water mark. Once the excavation was prepared, dried out and blinded, the two tanks were lifted in with a 30 tonne excavator under a load specific lift plan. Grant Ltd completed the works and handed back to the main contractor for the remaining site works.

Kishorn, Ross-shire

Overlooking the Isle of Skye, Kishorn is a small coastal village fronting a sea loch, where Grant Ltd were engaged to install a marker pole at the sea outfall pipe. Working in tidal waters, the challenge was to excavate a dry hole in which to build a foundation strong enough to withstand the wind and tides. A shored coffer dam was used which was dried out following each tidal inundation and allowed the concrete footing to be cast in standard manhole rings

Dunbeg, By Oban, Argyll and Bute

Dunbeg is a small village to the north of Oban where Scottish Water required a new sea outfall pipe for the upgraded waste water treatment works serving the village.

A temporary access track was laid alongside the old pipe to enable access ovr the mud flats. The new ductile iron pipe was laid on prefabricated concrete stools and finished with a headwall and storm flap. The old infrastructure was removed.

Previous Tidal and In-River Works Projects

• Client KMI/United Utilities, construction of a new water intake system in the river Eden
• Client KMI/United Utilities, construction of combined storm water overflow outlets
• Client KMI/United Utilities, construction of sewer pipe crossing of the river Ehen in Egrement
• Client KMI/United Utilities, construction of sewer pipe crossing to the river Derwent near Cockermouth
• Client United Utilities, construction of a number of sea outfalls, working below high tide water levels in the Ribble estuary near Preston   
• Client Scottish water, construction of sea outfalls, working below high tide water levels in the Tay estuary near Dundee   
• Client Scottish water, construction of a number of sea outfalls, working below high tide water levels in the Clyde estuary at Largs   
• Client Scottish water, construction of sea outfalls, working below high tide water levels at Dunbeg near Oban