Carterton District Council has bought $2.4 million worth of land bordering its wastewater treatment plant in a bid to reduce sewage discharges into the Mangatarere Stream.
The council said the purchase was "not directly related" to a wastewater consent appeal the authority last month took to the Environment Court.
But the land, between Dalefield and Gallons Rds alongside State Highway 2, would help gain consents in future as part of planned upgrades including the irrigation discharge of treated wastewater on to a much larger area.
Council chief executive Colin Wright said the existing site is used only as a treatment plant and waste transfer station and diversification of use was yet to be discussed.
The plant today comprises three oxidation ponds, a clarifier and sludge digester, extensive wetland cells for a third level of treatment, collection channels for eventual discharge into the Mangatarere Stream or redirection to a 2.1ha land irrigation discharge system.
"The land purchase is a strategy that's being taken for the future. It hasn't been established what other use that land could have. It's too early to say yet," Mr Wright said.
The council appeal centres on a three-year resource consent granted by Greater Wellington Regional Council that allows existing treated wastewater discharges to the Mangatarere Stream and the present 2.1ha system.
The Carterton council had sought a five-year consent and the appeal was made on the grounds that limiting the consent to three years would curtail planned upgrades and would "impose unnecessary costs" on ratepayers.
Further grounds included that council would not have time to fulfil consent requirements and there were unreasonable and inappropriate limits put on the ability to discharge to the stream in certain conditions.
Carterton mayor Ron Mark said council had been investigating improvements to its wastewater infrastructure for several years.
"We have recognised for some time that major changes will be required to future-proof the system to both protect the Mangatarere and meet the future needs of Carterton's growing population," he said.
"Securing the land when the opportunity arose was important in advancing the goal of discharging more wastewater to land over time as the community is able to afford it.
Mr Mark said the $2.4 million property purchase will be funded through borrowing "because it is not currently budgeted for and so that the cost can be spread over future generations who will benefit".
"Although it will not be possible to irrigate to this land year-round, the new block will, in future, allow us to minimise discharges into the Mangatarere Stream in the warmer months of the year when the stream flows are low."
The council has budgeted for a number of improvements over the next five years as part of a new resource consent. Proposed upgrades include another oxidation pond, an ultraviolet treatment unit and a new plant to reduce phosphorous from treated effluent.