Horowhenua District Council to achieve another first
Horowhenua District Council to achieve another first-of-its-kind in New Zealand
Horowhenua District Council is to become the first council in New Zealand to use a purpose-made native ecosystem at an operational scale specifically for the irrigation and further treatment of wastewater.
In a redevelopment of the Levin Wastewater Treatment Plant’s irrigation system, 10 hectares of the current exotic pine forest at the site, locally referred to as ‘The Pot’, will be replaced with manuka and kanuka trees as part of a five year trial to assess environmental benefits.
Research shows that manuka and kanuka root systems have unique properties that not only filter pollutants, but can assist in reducing leaching of nitrogen and pathogens into the underlying groundwater. The trial will also see other native species including kahikatea, pukatea, rimu, tawa and swamp maire planted for comparison.
Council’s Infrastructure Services Group Manager Gallo Saidy says the pine plantation is at full term and ready for harvest, providing an ideal opportunity for this “innovative trial”.
Mr Saidy says the $1.2 million project has been made possible after receiving $607,173 from the Ministry for the Environment’s Freshwater Improvement Fund.
“Best engineering solutions were used at The Pot when it was designed 30 years ago, including being the first pressurised wastewater spray irrigation system in New Zealand, resulting in a number of awards,” Mr Saidy said.
“However, using current and advanced technology, we can upgrade the irrigation system and along with establishing a native ecosystem this will significantly reduce contaminant leaching and will enhance biodiversity, protect vulnerable soils and improve water quality in the Waiwiri catchment.”
The 10 hectares of pine forest will be harvested from next month in preparation to install the revamped irrigation system. Manuka and kanuka planting is to start next year.
During the trial the site will be monitored and environmental improvements assessed, with scope for further areas of pines to be replaced with the similar native ecosystems.
For the project, the
Council has been working closely with Lowe Environmental
Impact Ltd and The Institute of Environmental Science and
Research (ESR), with input into the trial also involving
local iwi owners of The Pot, Northcott Research Associates
and Lincoln University.