Build concerns for water sites

VIABLE?: The proposed Black Creek storage lake, along with White Rock Rd, require further investigation after a geotechnical report suggested the sites could be too costly to develop. PHOTO/FILE

Initial geotechnical investigations in five areas where water could be stored in Wairarapa have found that there are no technical reasons to dismiss any of them at this stage.

However, the White Rock Road (Martinborough) and Black Creek (Masterton) options have been flagged as risks for increased construction costs, which may render them financially unviable.

The other three sites are Mangatarere, west of Carterton, and Te Mara and Tividale, north of Masterton.

The work was part of a pre-feasibility study to further narrow options for water storage and distribution schemes.

It potentially leads to selection of one or more schemes that show enough viability to undergo a more detailed full-feasibility study beginning in mid-2015. The investigations were carried out during April and May to identify and understand any geotechnical or geological issues that could affect whether a site was suitable for continued study.

Wairarapa Water Use Project director Michael Bassett-Foss said the geotechnical information would help better define construction costs which would affect the cost of water and the viability of any scheme.

"Until this year site investigations have involved desktop research and visual inspections only. This was the first time we have conducted any physical work - digging test pits, taking soil samples and looking more closely at surface material and land features. The work was at a preliminary level, based on observations and engineering judgement, rather than full analysis," he said.

"There were no major surprises but we did learn more about several geological issues at the White Rock Road and Black Creek sites which we would like to look at further as soon as possible.

"The aim of this would be to establish whether these issues were sufficiently significant to discount either site."

An assessment of water distribution arrangements for each site is to be completed by October. "We expect to be in a position by December this year to start discounting the least viable storage sites, helping to give affected landowners certainty."

- For information and reports on Wairarapa Water Use Project: www.wairarapawater.org.nz