Guideline for Assessing Technical Resilience of Three Waters Networks

Simplified assessment method

This guideline provides a framework for assessing technical resilience of three waters piped assets.

It has been prepared to support local authorities and the private sector (including asset managers, operators and engineers) at local and regional levels with assessing technical resilience and in developing strategies to improve network resilience, and inform pre-event planning and post-event emergency support and recovery. read more

Spatial Correlations of Underground Pipeline Damage in Christchurch

The Christchurch Earthquake Sequence of 2010-2011 caused extreme and widespread damage to the 3 waters pipe network of Christchurch. Most of this damage was caused by liquefaction and lateral spreading. Researchers and practitioners have learnt many lessons in assessing liquefaction damage from these experiences. This report develops tools to assess the potential for pipeline damage based on correlations with liquefaction-induced ground movement and CPT-based liquefaction metrics. The correlations can be used for pre-event estimates as well as post-event rapid triage of pipe damage. Key inputs to the assessment are pre and post-event LiDAR surveys; satellite imagery; CPT-based assessments of liquefaction vulnerability and Peak Ground Velocity (PGV). read more

Wastewater Renewals Framework – Gravity Pipes

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 document provides guidance for asset managers on the renewals process and discusses how to communicate issues related renewals planning to decision makers such as senior management or councilors, finance staff and auditors. The questions that decision makers should expect asset manager to address when proposing renewal plans are summarized.

While this document is focused on the renewal of gravity wastewater pipelines, the concepts and recommendations provided in this document are generally applicable to potable water and storm water networks.

Review of New Zealand Pipe Inspection Manual

NZPIMThe 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 Guidelines

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.

This document is the output of the workshop in which the framework for this guidance material will be created.

Levels of Service Performance Measures for the Seismic Resilience of Three Waters Network Delivery


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:

  • Robust physical assets with key network routes having appropriate alternatives, and response arrangements in place
  • Effective co-ordination arrangements (pre- and post-event)
  • Realistic end-user expectations and appropriate measures of backup arrangements.
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