A proposal to introduce intensive dairying to Hawea Flat is concerning some residents. However one of the reassurances the Otago Regional Council gave may not be very reassuring:
“Your septic tanks are a bigger risk,” the Otago Regional Council’s John
Threlfall told Hawea Flat residents yesterday at a public meeting to discuss the
effects of intensive dairy farming on their water quality.
Held in the Hawea Community Hall, the meeting was addressed by council
chairman Stephen Woodhead and the council’s environmental information and
science director Dr Threlfall. . .
Dr Threlfall said the council wanted to allow good farming to progress, and
at the same time maintain and protect water quality.
“We cannot offer any guarantees,” he said. “But your septic tanks are a
bigger risk, and local monitoring will indicate water quality changes long
before deterioration becomes dangerous.”
Dairying gets the blame for water quality issues but domestic and industrial waste can be at least as much a problem.
However, that septic tanks are a greater risk doesn’t mean there is any serious risk.
Dr Threlfall said: “It’s our responsibility to enforce ORC’s water plan. Our
permitted rules are quite stringent and aim to maintain present water quality
levels.”
Mr Woodhead added that the 400 dairy farms in Otago are inspected annually,
and that it would take “one helluva an event” for dairy effluent to pollute
local rivers.
Bad publicity about dairying is some places doesn’t mean it’s causing problems everywhere.
The ORC told a meeting in Oamaru last week that all but one of the waterways in the district had no quality issues. The one issue was in a small part of the Waiareka Creek which was much healthier than it had been before the North Otago Irrigation scheme was launched.
The creek had been little more than a series of stagnant ponds for most of the year, now it flows continuously which has improved the water quality and the habitat for fish and insects.
Septic tanks on alluvial soils can be a problem but there is nothing that cannot be solved by a combination of ‘Septics’ with the solids being ‘collected for disposal’ and the effluent water being piped to a lined oxidation pond for further treatment.
A system that has been installed on a limited basis already and has the potential to totally capture any potential effluent leakage. Tekau Bay, a settlement on Akaroa Harbour has piped its liquid waste to a plantation above the settlement for evaporation dispersal.
Duvauchelle retains its solids for removal to the City station at Bromley and pipes its liquids to sea not ideal but goes someway to reducing a problem, The sea pipe could be replaced with a small oxidation pond on land, expensive but not impossible.
The old Akaroa Borough will be forced to set up a similar solution but locating a settlement pond will be very difficult and we cannot continue with harbour outfall.
The output of an “Oasis Clearwater System” septic produces a very low pollution liquid waste and solids are “user Pays”.
We have recently installed a system in the Sounds which is similar to an Oasis system, where the water which comes out is supposed to be suitable to drink, although i haven’t been game to try it. It goes through a series of filters and a UV light before being irrigated through trickle irrigation pipes around the section. The tank also very rarely needs cleaning, unlike most conventional systems where the solids need to be pumped out every 3 or 4 years.