MJ Abbott

Installation of Wessex Water public water main under Self Lay Agreement (SLO)

Lower Pertwood Organic Farm, Hindon, Wiltshire

Project summary

New water mains adopted by Wessex Water

Having already established a long working relationship with Lower Pertwood Organic Farm, MJ Abbott was the client’s first choice contractor to lay a new public water main, on behalf of Wessex Water, to supply four domestic properties at the bottom of the farm.

The four properties were supplied with water from the farm’s private water supply network (borehole), and as the properties were privately owned, it made commercial sense to have the properties connected to the Wessex Water network and billed direct. As the cottages were remote from the Wessex Water network, a network extension was required.

Working under a Self Lay Agreement (SLO) with Wessex Water and Lower Pertwood Organic Farm, MJ Abbott were contracted to lay a new 63mm MDPE water main, which would be adopted by Wessex Water upon successful completion of the works.

Some 1700 linear metres of 63mm MDPE blue water mains were installed from the Wessex Water network at their reservoir at Lords Hill to the cottages. A second 63mm MDPE black water main was also laid to be connected to the farm’s private network, to replace some old leaking steel pipework.

The route of the proposed new water main had to cross through SSSI ground and under Scheduled Ancient Monuments so working with Natural England and English Heritage, the necessary permissions were obtained and a watching brief was required under the supervision of local approved archaeologists.

Due to the topography of the site, pressure reduction valves with metered bypass were installed, along with air release valves, in large concrete valve chambers.

An electrical supply was required at the Wessex Water reservoir at Lords Hill, so to save on installation costs, a high voltage cable was also laid in the common trench to bring electricity from the cottages.

As MJ Abbott Ltd were on site with the necessary trenching equipment, further works were also carried out for Wessex Water as part of their own major network upgrade works.

The full scope of work carried out by MJ Abbott comprised:

  • Full easement strip and replacement of topsoil on completion
  • Installation of 1700 linear metres of 63mm MDPE water with granular backfill
  • Installation of 1900 linear metres of high voltage electric cable
  • Installation of marker tapes for pipes and cables
  • Installation of air valves, pressure reduction valves, water meters, hydrants and domestic water meters
  • Chlorination and pressure test of water mains on completion.

The works were carried out to the full satisfaction of both Lower Pertwood Organic Farm and Wessex Water, and the water mains were duly adopted into the Wessex Water network.