Providing an asset to the community that safeguards lives.
Dairy Flat Roundabout
Client: Auckland Transport
- 7 MSE walls
- 2,784 m² of Significant Ecological Area
- 5 major stages of traffic works
- 6 hours to install the 2 unique Filterra units
Project Background
The Dairy Flat Highway Coatesville Riverhead Highway roundabout project embodies engineering excellence, promoting circular economy principles and providing an asset to the community that safeguards lives.
Categorised as one of New Zealand's top 100 high-risk intersections, the $10 million Auckland Transport project comprised critical safety improvements.
Project Overview
Constructed over 16 months, the project involved bulk earthworks, carriageway widening, construction of a roundabout, road remediation, improved alignments, and safety measures such as barriers and road markings, drainage and landscaping.
Seven MSE walls/batter slopes were constructed beneath the road carriageway to reinforce and support the road carriageway alignment and roundabout configuration.
The discovery of the historic slip on wall 3, located on the corner of Dairy Flat Highway and Coatesville Riverhead Highway, instigated extensive redesign and modification to the methodology.
Loose material (engineered fill) discovered during the excavation of the existing wall dated back to a slip in 1954.
A critical component of the project was the installation of two prototype Filterra Units. The stormwater provision, the biggest of its kind in New Zealand, is crucial for protecting the natural ecosystem in this Significant Ecological Area (SEA). The unique units manufactured by Stormwater 360 offer an innovative, cost-effective and low maintenance solution.
The Dempsey Wood project team installed the two 16T units below ground in two sections. Using a 250T crane, the installation, which took approximately 6 hours, required a one-lane closure to ensure the safety of road users and the public.
Dempsey Wood was a pro-active contractor who worked with the designers and client to address some unforeseen conditions.
Blue Barn
Mark Thomas,
Principal - Land Development
Outcomes
An exemplary project with an excellent environmental record and numerous sustainability initiatives, the project received a "Commended" at the recent Engineering New Zealand Arthur Mead Awards, in the under $10m category.
The project team achieved an outstanding result, despite numerous challenges (including COVID-19) working tirelessly, to ensure successful delivery for the stakeholders of the Coatesville, Riverhead and Rodney communities.
