Innovative Stormwater Treatment Asset Conversion at Auckland Motorways

The New Zealand Transport Agency’s Auckland Motorway Alliance (AMA) maintains and operates the Auckland motorway network and is dedicated to improving the motorway experience for customers and stakeholders. The AMA have a large variety of stormwater management assets and must ensure that they deliver the right level of network service, and that safe and healthy outcomes are achieved for people, plant and the environment.

This paper outlines details of a NZ Transport Agency “Think outside the Box” award winning, innovation project. The project involved the conversion of an unsafe and inefficient Stormwater treatment device, from a Sandfilter into a StormFilter. This project is a great example of how a project team can ‘innovate’ to achieve ‘resilient’ and ‘future ready’ outcomes.

Monitoring, maintenance, and operational activities on an existing operative sandfilter exposed contractors and the public to health & safety risks. These risks involved exposure to highly toxic gases, confined space entry and required traffic control measures that resulted in a loss of network efficiency and availability.

Through positive collaborative engagement with specialist stormwater management suppliers, Stormwater360, the team were able to assess the technical and physical viability of the proposal to convert the Sandfilter into a StormFilter.

To support this innovation a business case including a net present value (NPV) assessment was undertaken, and a managerial approved variation to existing Resource Consent was secured to enable the activity.

This innovative project involved retrofitting hydraulic & operational enhancements to the existing infrastructure and partnered design and construction to deliver functionally successful and innovative outcomes.