Lake's level at Hawea Flat 'one factor' for aquifers

Lake Hawea. Photo / ODT files

While the groundwater level in Hawea Flat is low for this time of year it is not historically low, the Otago Regional Council says.

Last week an organisation called the Upper Clutha Farm Group issued a press release which raised concerns about the level of Lake Hawea and its impact on the groundwater level in Hawea Flat.

The press release said some residential water bores in the area were historically low and were close to drying out.

The farmers said they were worried the situation would only get worse once irrigation started, and they would be blamed for any water shortages.

The ORC's director of engineering, hazards and science, Gavin Palmer said the level of the lake was only one factor which influenced the level of the Hawea aquifers.

Similar levels were recorded in 2008 and 2012 and those levels were well above the lowest levels recorded.

Before the lake was dammed in 1958, its level was about 20m below what the average level was now, which meant the groundwater level then was also much lower, Dr Palmer said.

Aside from rainfall, the three key influences on the groundwater in the Hawea aquifers were: the level of the lake, more efficient irrigation practices and the impact of new housing developments.

Four bores were used to collect data on the aquifers and two new monitoring bores would be drilled next month.

The Upper Clutha Farm Group representative, Queenstown lawyer Michael Walker said the group did not wish to respond to the ORC's comments on the water levels.

Hawea Community Association chairman and Hawea Flat resident Paul Cunningham said he had not heard of bores running low or completely drying out.

"It may be going on but nothing has been bought to my or the board's attention, but we will be keeping our ears to the ground, so to speak, now the issue has been brought up.''
There had been a reasonable amount of rain in the past month and the level of the lake had started to rise again, Mr Cunningham said.

"Lets hope it stays that way.''

He was pleased the ORC would install more monitoring bores which would provide a better understanding of how the aquifers worked.