Renewals - turning projects into programmes

Beth Parkin, Stantec & Wellington Water (seconded)

Historically, in New Zealand there has been under-investment in water infrastructure for many years. This has created an increasing backlog of required asset renewals and increased maintenance of aging networks that have not been replaced as they reach the end of their expected service life.

The Wellington Region is no different, and Wellington Water is planning for the significant increase in its client Councils’ renewals budgets in the Long-Term Plan. In addition to this, Government funding is forecast to become available as part of the wider water sector reforms. As well as building capacity in the industry to meet this backlog, there is also the need to increase the efficiency of project delivery.

The Wellington Water Fast Track Renewals programme is a $15.4 million trial programme delivering packages of pipeline renewals work for water and wastewater focused on addressing known issues in the Wellington region over a period of less than 12 months. The programme is partly funded from the Government’s Post-COVID Stimulus Funding and was delivered in addition to Wellington Water’s Financial Year 2020-21, $130M Capital Expenditure programme.

The programme delivery model is commonly used in the United Kingdom, and involves identifying areas (rather than pipes, or sections of pipe) that require renewal and undertaking a cost-effective planned approach to their renewal.

This programme trialled moving away from targeting pipe renewals on a street-by street basis and moving to a delivery model which targeted area wide improvement of service. Due to the timing constraints from the Government Stimulus funding - all funding must be spent by March 2022 the trial programme focused on low-risk renewals where engineering standards are well established, and complex designs were not required. The design information provided to Contractors was minimised, providing only overview or simplified plans and the programme has been used to consolidate Wellington Water’s library of standard design details and specifications, saving time in the design phase.

The programme has also adopted a “think trenchless technology first” philosophy. Trenchless technology significantly reduces the impact on the community during construction and generally reduces carbon use in the build. Trenchless technology can also reduce the construction programme and Health & Safety risks associated with heavy machinery movements and open excavations. A Corridor Approach (renewal of both water and wastewater) was trialled for some Councils. The programme aims to renew continuous lengths of pipe to ensure parts of the network are not “left behind”.

Analysis of available pipe data (condition information, maintenance issues, bursts, collapses, etc.) was completed and a “long list” of potential renewals identified. The long list was generally made up of pipes that were either already failing/known to be in poor condition or were past or very close to their expected lives. Wellington Water operations and investigations engineers were then engaged with to refine the list down to a “short list” of proposed works.

Three teams are delivering these programmes of work which have been formed from Wellington Water’s Consultancy and Capital Expenditure (CAPEX) Contractor panels. All Consultants and Contractors are directly appointed saving a significant amount of time in the procurement phase of the programme, reducing procurement costs, and enabling a different type of team structure to be developed where two of the three teams were led by a contractor.

The approach to deliver this programme was overseen and supported by a Steering Group made of up representatives of Wellington Water and the Consultancy and Contractor panels. The delivery approach developed is adaptable and is planned to be used to deliver a six-year rolling programme incorporating more complex renewals and the potential for coordination with other utilities.