Letters: Guessing around groundwater bores isn't good enough

Concerns raised by local residents have caused the NRC to investigate water usage by MWWUG

MWWUG (Motutangi Waiharara Water User Group) is a group of 17 orchard owners applying to the Northland Regional Council for groundwater for irrigation.

If granted all the water they are applying for then no consents will be available for anyone else in some areas. However MWWUG will be in a position to on-sell their consented water if some NRC plans go ahead.

Concerns raised by local residents have caused the NRC to investigate water usage by MWWUG and others in the surrounding area.

At least five of the MWWUG had no consent at all for the groundwater they have used on their established orchards. In some cases they have allegedly been using this water illegally for many years.

Such poor behaviour from members of a group that will potentially monopolise groundwater causes us to question the integrity of the group as a whole.

The MWWUG application to the NRC for groundwater abstraction is based around a computer-generated model which estimates the effect of multiple bores pumping from the groundwater system. It used actual data obtained from pumping three bores, and extrapolated that limited information to get an overall view.

Once again local residents have found errors with this model, as they have with models used in other groundwater abstractions. The ground level used for at least two of the three bores was wrong, in one instance by over seven metres. This is because the experts involved had not surveyed what the the actual ground level was, but estimated it.

It is not acceptable in a project of this size that the experts should be making calculated guesses about the most basic datum levels and be so inaccurate. It is impossible to have faith in such a model when local residents find errors that the so-called experts have missed.

The Aupouri aquifer is one of the last pristine groundwater sources in New Zealand. The possibility of increasing nitrate levels affecting the aquifer has already been raised.

Contamination from areas of high-intensity land use will eventually impact on the aquifer, as has happened elsewhere in this country and all over the world.

The aquifer water should be used for human and animal consumption first and foremost, and used with great care for any other purpose.

RICHARD SUCICH
Waipapakauri