Planned improvements to wastewater-disposal facilities at Lake Hawea have been backed by the Otago Regional Council in a move that will save ratepayers millions of dollars.
The upgrade of the township's facilities also will remove environmental risks to the Hawea River, which previously was the discharge outlet for wastewater overflows during periods of heavy rainfall.
The Queenstown Lakes District Council plans to install a $300,000 spray-dispersal scheme, which has been granted two resource consents from the ORC permitting the discharge of treated wastewater on land and into the air.
QLDC infrastructure services general manager Mark Kunath said it was estimated the revised scheme upgrade would save about $5.2 million in capital costs, which otherwise would have been paid by Hawea ratepayers.
The new spray-dispersal upgrade will connect to the QLDC's existing oxidation and trench-system facilities at Hawea, off Domain Rd.
Treated wastewater will be sprayed through an irrigation system across a neighbouring 2.5ha block of farmland during the summer months, he said.
Crops, such as lucerne and ryegrass, have been identified as suitable to be grown at the site, with a view to sourcing an income from it.
"We're hoping it will be a test case which can show how treated effluent can be used," Mr Kunath said.
Funding bids for the upgrade would go before the council for approval as part of next year's annual plan budget forecast, he said.
The planned upgrade comes a year after QLDC engineers went back to the drawing board to find a more affordable and appropriate solution to ease growing wastewater infrastructure needs at Hawea.
A project team had revised engineering plans to come up with an "extremely cost-effective solution for the community", which would also future-proof the township for growth, he said.
After completion of the upgrade, no further significant new capital works expenditure should be needed for Hawea wastewater treatment until about 2022, when the ORC consents expire.
Down the drain
Lake Hawea wastewater upgrade details:
• A spray-dispersal system will discharge treated wastewater via an irrigation system on 2.5ha of land neighbouring the existing oxidation pond off Domain Rd.
• Crops will be grown on the site.
• Estimated cost of five-year implementation: $300,000.
• Upgrade removes previous discharge of wastewater to Hawea River during heavy rainfall periods.
