Ground Investigations Underway

Ground investigations are underway to help us develop the design of the proposed Melling transport improvements and other RiverLink projects. You may notice this work going on back in July near the existing Melling Bridge and work will commence again on 4 November. This round of drilling will be for 1 to 2 weeks.

What is the purpose of the investigations?

The Transport Agency will use the information gathered from these investigations to help develop the preliminary design of the preferred interchange option – a diamond interchange connecting directly with Queens Drive. The preliminary design is being developed as a part of the Detailed Business Case (DBC) for the transport improvements.

The ground information helps us to understand what type of design is needed to construct a resilient bridge and interchange. It’s also important as it will help us ensure that any future transport improvements are designed to protect the Waiwhetu Aquifer – an important water supply for the whole region.

The DBC is an important phase of the project. The Transport Agency expects to complete and consider the DBC for the Melling transport improvements by early 2020.

Will I be affected by the ground investigation work?

There will be work taking place at six sites spread across both sides of the river, in areas around the Melling and Riverbank car parks. One of these sites will be a borehole which will take around four days to complete. The remaining five sites will be CPTs (Cone Penetrometer Tests) which use a cone-shaped instrument to determine how much load can be put on the ground – will take one day each.

All work will be done between 8am – 5pm, and work areas will be fenced off to keep people safe. Four parking spaces at Melling train station will be temporarily restricted during the borehole work. We do not expect this work to cause any other impact to people using the road or using Melling train station.

Further ground investigations

Investigations will then continue at various sites on both sides of the river, from upstream of Melling Bridge to the Ewen Bridge. This work will inform the design of the new stopbanks, a large retaining wall which will support the promenade, piers and abutments for the pedestrian cycle bridge. We also expect the findings to help us understand how a nearby major fault line could impact our designs and how best to protect the aquifer.

At some locations, there will be limited access to the river and traffic management in place at various times. The map below shows where the work will be done.

Follow the RiverLink Facebook page for regular updates on this work.