Bore water below drinking standards

More than a quarter of bores in Southland have groundwater bacteria levels which do not meet national drinking water standards, indicating the presence of microbes that can cause illness in people and animals, tests show.

The results are revealed in Southland's annual environmental report card, which shows there is room for improvement across a range of sites monitored.

Each year Environment Southland creates report cards for groundwater quality, groundwater quantity, lake water quality, river and stream health, rivers and rainfall, soil moisture, surface water abstraction, air quality and water quality for bathing and shellfish gathering based.

The results of the 2012-13 year show groundwater bacteria levels did not meet national drinking water standards in 27 per cent of bores sampled.

In addition, 50 per cent of bores sampled for nitrate indicated significant impact from land use activities.

Nitrate concentrations show general groundwater deterioration across the region.

Just three of the eight shellfish water quality sites complied with the national guidelines. The cockle beds at Toetoes Harbour and Jacobs River Estuary had the highest levels of bacteria. Lakewater quality was a different story however, with Lakes Te Anau and Manapouri reported as having excellent water quality. Coastal lakes fared worse, with some sites having poor water quality.

Waituna Lagoon had a lower than average trophic level this year because of being opened to the sea for extended periods, which prevented the aquatic vegetation from recovering. This was not considered a long term solution for its water quality issues.

River and stream health also showed room for improvement. Waterways in lowland Southland have high levels of sediment nutrients and faecal bacteria, often above water quality guidelines.

In particular, the Waimatuku, Waihopai, mid-Mataura, Waituna/Awarua, Makarewa, Lower Oreti, Lower Mataura and Catlins zones had nutrient levels above the guidelines.

Faecal coliforms, which indicate high levels of bacteria, were found in levels above guidelines in the Waihopai and other intensively farmed areas.

Soil moisture levels across the majority of sites were at similar levels to the previous year during winter and the most of spring. However a late summer dry spell resulted in drier than average well into 2013, with levels not seen since the 2007-2008 drought.

Air quality national standards were exceeded on 12 days in Invercargill over winter and three days in Gore.

Freshwater guideline breaches were up slightly but well below the long-term average.

Marine bathing sites were top of the class for their reports as 13 site results were the best recorded since 2004.

Freshwater bathing quality results showed 14.7 per cent of samples breached Ministry for the Environment guidelines, which is slightly up from the previous year but below the long-term average.


The Southland Times