Assessment of Operational water Effects for the Puhoi to Warkworth Rons Project
Stormwater Conference
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The Puhoi to Warkworth Project realigns the existing SH1 from the Northern Gateway Toll Road at the Johnstone’s Hill tunnels via an 18.5 km four-lane dual carriageway road alignment that will tie into the existing SH1 north of Warkworth.
An Operational Water Assessment report formed part of a suite of technical reports prepared for the Transport Agency to inform the Assessment of Environmental Effects and to support the Resource Consent applications and Notices of Requirement for the Project.
The Further North Alliance was formed to develop the Transport Agency’s applications to the Environmental Protection Authority. The Alliance included the Transport Agency, engineering consultants (GHD and Jacobs SKM) and lawyers (Chapman Tripp), plus a number of expert sub-consultants. The Alliance proved to be a vibrant working environment where an extremely demanding timeframe demanded efficient and innovative approaches to ensure sufficient assessment of effects were satisfactorily carried out.
A variety of measures to avoid, remedy or mitigate adverse environmental effects were designed into the Project’s operational water systems based on a best practicable option approach. The mitigation measures were determined through a robust evaluation of options and drawing on the collective knowledge and experience within the Alliance.
The operational water aspects of the indicative design features 27 constructed wetlands, 40 culverts, seven large viaducts and five bridges, of which nine are required because of stream / river crossings.