An Existing gas pipeline (Barrow - Vickers - Millom) that passes beneath the Duddon Estuary, Cumbria.
Inspections revealed that during recent storms the bank at the edge of the sands, near Askam-in-Furness, had severely eroded, exposing the pipeline and leaving it at risk of damage.
Northern Divers were employed through their existing National Framework Contract with National Grid to undertake the survey, design and site works in order to maintain protection to the gas pipeline.
The design comprised excavation along each side of the pipeline to accept the installation of gabion baskets, fill between with Type 1 aggregate to cover the pipeline and placement of gabion mattresses on top. Rip-rap stone was also placed around the works to offer further protection. The pipeline was recoated to repair minor damage that had occurred.
-1719923412.png)
Eroded bank exposing gas pipeline beyond previous protection works. Timber steps are located immediately adjacent the pipeline and provide public access to the beach.
Because a main public access to the sands located immediately adjacent to the work site could not be closed, priority was given to the public and the works ceased whenever a member of the public used the access.
Pipe protection mats were installed over the buried pipeline and other nearby services to prevent potential damage caused by plant movements. Due to the proximity of the gas pipeline, Permits and closely monitored the works throughout.
The design of the protection was a direct continuation of protection that was installed a year previously. As such, the proposal had been proved to be effective and its low-profile nature was acceptable to Natural England, who understood the need for the works but were keen to preserve the local natural environment as much as possible.
-1719923525.png)
Access ramp down to the sands washed away by storms.
The works were within the Duddon Estuary Site of Special Scientific Interest, Special Protection Area, Ramsar site and Morecambe Bay Special Area of Conservation. As such, in order to obtain consent from Natural England, the works had to be planned and executed to their satisfaction.
All mobile plant was altered to run on biodegradable oil. All plant was refuelled away from the sands. Drip trays and spill kits were available to prevent pollution by fuels or chemicals.
All waste materials were taken off-site and disposed-of in accordance with the Site Waste Management Plan.
The landowner, Local Authority and Natural England were consulted on the proposed works from the beginning of the scheme and kept informed of progress throughout the construction phase.
-1719923573.png)
Reinstated access ramp down to the sands. The reinstated ramp was left in place to allow access for future maintenance works.
200mm gas pipeline, NL0014 Reading Branch, crosses a watercourse, The Cut, just north of the M4 near Maidenhead.
Inspections had revealed that, because of scour partly caused by upstream vegetation and debris, a section of the riverbank had eroded to the point where the pipe’s swan-neck, previously within the bank, had become exposed, putting the pipeline at risk of damage.
Northern Divers were employed through an existing National Framework Contract to undertake the survey, design and repair of the eroded bank in order to maintain protection to the pipeline.
