The replacement value of New Zealand’s wastewater networks is significant, being estimated to be NZ$15.8 billion (LGNZ, 2014). Making good investment decisions is therefore very important. This document is intended to be a resource to assist public sector organisations make evidence‐based decisions on the renewal of gravity wastewater pipelines.
The New Zealand Pipe Inspection Manual (NZPIM) is a document that is extensively used by the water industry to assess the condition of waste and storm water pipes. It was last updated in 2006. Since that time, there have been a large number of technical advances. In addition, the NZ$100 million spent on inspecting the Christchurch 3 waters network after the Canterbury Earthquake Sequence provided a number of lessons that need to be captured in an update. As part of the Evidenced-based Decision Making for 3 Waters Networks project, the Quake Centre with the asistance of EQC engaged ProjectMax to undertake a full review and scope of the required changes to the NZPIM. This exercise has now been completed and the report is out for comment across the water sector.
Pipe Renewals (working title)
The Pipe Renewals Programme is a collaboration between the Quake Centre, Water NZ and IPWEA to develop an integrated suite of guidance material. This guidance aims to foster national alignment of best practice investment decision making across the whole of New Zealand. It is expected that this project will take about 10 years to finish. The document below sets out the road-map for this programme.
In 2014, the total replacement value of the 3 waters assets in New Zealand was estimated to be about NZ$45.2 billion. As these assets are upgraded or replaced, many difficult decisions will need to be made in respect to the trade-offs between Levels of Service, capital costs, operating costs and management of risk. The aim of this project is to provide guidance and tools to enable New Zealand Water organisations to implement advanced asset management processes to develop inspection, maintenance and renewal strategies for pipework in potable water, waste water and storm water systems.
Learning from the Christchurch Earthquake sequence and other disasters has highlighted the need for New Zealand’s 3 Waters Services to be seismically resilient. In the context of these guidelines the key aspects of a resilient system are: