Richmond South – Trunk Watermain

As part of Tasman District Council’s direct procurement process, this was a great project to be a part of as Donaldson Civil was involved from the design phase right through to completion and livening of the watermain.

Several workshops took place between the design team, the client and Donaldson Civil to work on the design and ensure the best constructability and value for money for the client. As well as other aspects such as the effect the project would have on stakeholders including public for traffic management, pedestrians through site, nearby shop owners and residents.

Physical work started in July 2022 with a 600mm pipe being thrusted under State Highway 6. With an exceptionally wet winter causing the water table to rise significantly this was a particularly challenging portion of the job. With up to 3x 150mm pumps running in tandem to several sediment treatment devices, before the water was discharged to the stormwater system. After this thrust, another was completed under state highway 60.

With both thrusts completed the team concentrated efforts into laying the 450mm PE watermain. The first section required the use of trench shields, where 40m was opened at a time and the string of PE pipe pulled through, then an in-trench butt-weld completed. The next section was inside grape vines and paddocks so could be benched, which meant a much simpler and faster installation was achieved. All butt-welding, including test welds, were completed by Donaldson Civil staff.

Finally, some tricky installations through a live creek, and connections at each end were completed, with all testing and disinfection completed before the required period by TDC.