Ask Phoebe: Drillers after Orakei sediment

A drill rig was used to bore deep into the sediment of Auckland's Orakei Basin to retrieve ancient evidence of volcanic eruptions. Photo / Supplied

Can you enlighten me as to the reason for the small drilling rig moored in the middle of the Orakei Basin lately? (Hope they know it's an extinct volcano).

- Philip Oldham, Remuera

It's precisely because it's an extinct volcano that the drilling is taking place.

A recent Herald story explained that scientists from the University of Auckland's School of Environment have drilled more than 100m beneath Orakei Basin in a bid to reveal the explosive history of ancient Auckland. The samples they retrieved from deposits of lake sediment will detail volcanic eruptions in the region over the past 140,000 years.

Orakei Basin is used because although now it is a shallow estuary, it was for most of its history a deep freshwater lake collecting sediment and volcanic ash. The lake sediments are mostly finely layered, although larger eruptions formed thicker layers.

The samples taken from Orakei Basin might also help scientists reconstruct the region's climate over the past 100,000 years.

I noticed in Ewington Ave there is a new driveway going through to the building site behind the Countdown supermarket. As I understand it semi-trailer delivery trucks will be using this entrance. The road is already very narrow for two cars to pass let alone these big trucks. Could you enlighten us on what is to happen?

- John Sumner, Auckland

The main elements of the expansion are as follows:

• Removal of the existing dwellings from residential properties at 114 and 116 Valley Rd to accommodate an expansion of the existing supermarket car park;

• A 1350m2 extension of the supermarket building on its southern side. The extension is to be located behind an existing row of shops;

• Relocation of the existing service and loading area and loading dock from the Valley Rd frontage to the south side of the supermarket. The new service and loading area will be accessed from Ewington Ave and will require removal of one house to provide access.

The entry to the new service area will be from the existing driveway between the main car park and Ewington Ave. It will require relocation of the footpath and introduction of a pedestrian crossing on that footpath.

Trucks will thus be separated from the main customer car park on Valley Rd, and conditions for pedestrians across the vehicle crossing at the Valley Rd entrance to the main car park will be improved.

The Valley Rd entrance will remain in its existing location but its grade will be raised to reinstate an at-grade footpath, and a central refuge will be provided.

The development will bring about some changes to the transport context of the site and the rerouting of commercial vehicles is considered the most significant of these changes. The ability of Ewington Ave to accommodate the expected size and volume of trucks has raised questions, but with some mitigation the access is considered acceptable.