- Barton-on-Sea - Emergency sea outfall
- Bacton Gas Plant - 900mm steel pipeline
- Isle of Grain - Heavy fuel oil pipeline relocation
- Isle of Grain - 600mm gas pipeline
- River Severn - 1.7km sewage outfall
- Rugby - 4km slurry line replacement
- Teesside Gasport - 1km river crossing
- Grain CHP - Heat pipe microtunnels
- Robin Rigg Wind Farm - 800m drilled landfall
- Yantlett to Stoke - 1550m pipeline
- Orkney - 600m twin drilled landfall
Case Study PDF
"One of the drills was carried out in extremely difficult conditions... And was carried out in a spirit of co-operation and teamwork, with a Stockton Director resident on site during the latter stages."
TJ Brent Ltd
1.7km seweage outfall
1.7km Sewage Outfall in Tidal Estuary
- Challenging marine conditions
The project was to fabricate and install a 1.7km HDPE gravity-fed sewage outfall within the tidal River Severn estuary. The pipeline consisted of several diameters up to 500mm, and included a 60m horizontal directional drilled outfall. 700m of the pipeline was installed above the high-water mark along the south-eastern banks of the river with the rest of the line being installed within the inter-tidal zone, including the HDD work. This section of project also took the pipeline over a rock outcrop known locally as the Aust or Black Rock.
Due to the particular challenges of working within an area well-known for a great tidal range and fast currents SDL carried out extensive risk assessments before work commenced. The risks were not restricted to the inter-tidal zone and working practices were introduced to ensure safe-working throughout the project. Measures taken included the provision of safety wardens to ensure all personnel were logged in and out of the inter-tidal zone and to monitor the condition of the cliff face throughout the works. Specialist PPE equipment was also provided. Before every project SDL will complete a series of assessments covering risk, health and safety and environment. With experience of working in challenging conditions, both on-shore and marine environments and are very familiar with the many environmental constrains present along most pipeline routes. A commitment to minimising any works done is inherent in the SDL approach.
The pipeline route is located within an internationally important site for wintering birds, protected as a SSI/RAMSAR/SPA site, and is known as an area of archaeological interest. In addition, the available project window was restricted to a period of June to October to safeguard the life-cycle of the 'Shad' that spawns in the area, coupled with planning constraints linked to protecting the foreshore salt marsh and the Aust itself this significantly impacted operations - especially plant movements and refueling.
- 1.7km HDPE pipeline installation.
- 100m HDD.
- River Severn estuary.
- Large tidal range and fast currents.
- HDD drill and pipeline installation within the inter-tidal region.
- Major environmental constraints.
- Tight window of opportunity for project execution.