Hunua 4 Water Main, New Zealand

Watercare provides water and wastewater services to around 1.5 million people in the Auckland region of the North Island, New Zealand. The company commissioned the Hunua 4 water main project as part of its long-term supply strategy to cater for the region’s future growth, including improving water supplies to the southern suburb of Manukau and providing system redundancy to the central business district.

The project involves constructing a new 28km pipeline between Watercare’s existing reservoirs at Redoubt Road in Manukau Heights and the Khyber Pass reservoir complex in the city centre. Stage 1 involves building the water main from Manukau to the suburb of Epsom. It consists of over 22km of pipeline ranging in diameter from 1.6m to 1.9m.

ECC Option A and SC

Watercare awarded the NZ$120 million (£59 million) NEC3 Engineering and Construction Contract (ECC) option A (priced contract with activity schedule) for stage 1 to a joint venture of contractors Fulton Hogan and John Holland.

Stage 1 is being constructed predominantly by open-cut methods through variable ground conditions ranging from soft peats through to hard basalts. There is also a tunnelled section under motorway SH1 and pipe bridges over motorway SH20 and several streams.

Work started in May 2012 and is due for completion in June 2016. By the end of 2014, over 14km of 1.9m diameter pipeline had been installed, with 7.5km of this already commissioned and in service.

The key equipment for the contract was procured using the NEC3 Supply Contract (SC). This consisted of valves and concrete-lined steel pipe, which had a total cost of NZ$55 million (£27 million).

Co-Located Project Team

To help foster a ‘spirit of mutual trust and cooperation’ between the parties as required by NEC, Watercare, the joint venture contractors and the consultants CH2M Beca and GHD are co-located in a single project office.

According to Watercare’s project manager David Moore, ‘The success of the NEC has been the way it encourages a proactive approach between the parties to overcome problems faced during construction − such as stakeholder issues, contaminated land, unknown utilities and traffic.

Through weekly meetings and collaborative working practices, all issues have been effectively monitored and managed through the NEC compensation-event process.  The approach has resulted in a very strong and positive working relationship developing between all of the parties.’

To assist in administering the project, Watercare is using a web-based contract change management application from NEC licenced content partner Conject.

Benefits of NEC

• Project team members are required to work in a spirit of mutual trust and cooperation.
• Encourages a proactive approach between all parties to overcome problems faced during construction.
• All issues are effectively monitored and managed through compensation events.
• Results in a very strong and positive working relationship within the project team.