Considerations and constraints

Roading layout

(Pictured above: the blue line is the "Mean High Water Springs line (MHWS) and the yellow is 7.5m (representative of minimum standard consented requirements). 

The existing road corridor is constrained with steep slopes on the landward side and the coastal marine area on the other side. This limits the available space to improve the road environment as any upgrade options that require additional road width would have significant implications in terms of the complexity of the work required, timing, and costs. They would also be subject to further regulatory and consenting requirements. 

The various roading constraints have been identified by engineers in March 2022 on a set of maps you can view here.

Tonkin+Taylor developed this virtual tour of Shelly Bay Road showing some of the ecological and environmental features of the area and the indicative footprint of the minimum standard consented requirements.

Ecological considerations

We know there are lizard populations and penguins nesting in the Shelly Bay area. We have commissioned lizard surveys to understand where the lizards are, and we are also working with Places for Penguins to understand how we can improve penguin habitat around this area.

We also know that the areas surrounding the road provide important marine and terrestrial habitats.  As planning for the upgrade progresses, we also need to assess the area for threatened plant species.  

Engineering constraints

The surrounding environment presents a number of engineering constraints that would have significant implications on the complexity of work, timing, and costs.

There are a number of geotechnical challenges to consider, such as the existing slope hazard, earthquake-induced slope failure risk, and liquefaction potential.

The coastal environment, tidal levels, and flood risk present constraints and risks.

We also need to consider the existing infrastructure and underground services in the road corridor, such as wastewater and telecommunications. You can find more information on the environmental constraints in the supporting documents.