TDC Brightwater SH6 Watermain Renewal
The project involved the renewal of approximately 1,650m of water main using 250mm OD PE pipe, along with new rider mains, property laterals, valve sets and fire hydrants. Works also included multiple State Highway crossings and waterway crossings at Borck Creek and Reid Andrews Stream.
A range of installation methods was used to suit the varying conditions across the project. Sections of the new main were installed along the existing alignment, while other sections were constructed off alignment using traditional trenching. Directional drilling was also used for sections of the project, including the highway crossings, allowing the State Highway to remain operational throughout construction.
Working within a live State Highway corridor presented significant traffic management and safety requirements. All works were undertaken to NZTA standards, with detailed traffic management planning required for each stage of construction. Directional drilling was particularly valuable at the highway crossings, minimising disruption to road users and avoiding the need to trench across the live carriageway.
Prior to any excavation, Donaldson Civil completed an extensive potholing programme to identify existing services and confirm ground conditions. The resulting data was analysed to determine the most practical and cost-effective alignment, providing the client with the best overall value while reducing construction risk.
Future requirements were also considered in the design and construction of the waterway crossings. At Borck Creek, where a significant upgrade is anticipated within the next five to ten years, the new main was installed to accommodate the future works and avoid the need for the pipeline to be excavated and relocated.
The project successfully delivered improved capacity and resilience to Tasman District Council’s water network, with Donaldson Civil completing the works significantly under budget. The combination of detailed planning, innovative installation methods and careful consideration of future infrastructure requirements resulted in a cost-effective and long-term solution for the client.
