Horizons Regional Council councillor Colleen Sheldon proudly accepted a New Zealand River Award on Tuesday night for the
Ōroua River.
The New Zealand River Awards celebrates waterways showing long-term trend improvements in water quality. A panel of
scientists judge sites throughout New Zealand using long-term data stored on the Land Air Water Aotearoa (LAWA) website www.lawa.org.nz.
This year’s awards focussed on dissolved reactive phosphorus (DRP) improvements. The Ōroua River was the most improved
in the Horizons Region, and second most improved nationally, with a 13.3 per cent improvement trend. Other water quality
indicators including total nitrogen, E. coli, and turbidity are also improving at this site, while the MCI state is Fair, with a score of 95.
This is the second ‘most improved’ award for the Ōroua since 2014 for improving DRP trends.
DRP is a measure of dissolved phosphorus compounds that are readily available for use by plants and algae, and is a
nutrient indicator. DRP concentrations are an indication of a waterbody’s ability to support nuisance algal or plant
growths (algal blooms).
Horizons natural resources and partnerships group manager Dr Jon Roygard says the site is part of council’s extensive
monitoring programme that measures water quality parameters upstream and downstream of major point discharge sources
throughout the region.
“The improved DRP levels are a great result,” says Dr Roygard.
“The Manawatū District Council has significantly invested in upgrading their wastewater treatment plant over a period of
time.
“Partial funding has also come from central government through the Manawatū River Leaders’ Accord’s Fresh Start for
Freshwater Clean-up project.”
Upgrade works included the reconstruction of existing ponds and the addition of clarification units, ongoing alum dosing
to remove phosphorus and residual suspended solids, and enhancing the standard of disinfection achieved by the UV
disinfection system.
This summer the plant has begun irrigating all treated wastewater to land for six months of the year while the Ōroua
River levels are low.
Independent Chairman of the Manawatū River Leaders’ Forum, Richard Thompson, says that the upgrade has been a
significant step in the long-term initiative to reduce the environmental footprint of Feilding’s community and
industries to restore the mauri of the Ōroua River.
“While the upgrade to the plant is the biggest intervention, there are other work programmes underway to help improve
the health of the Manawatū River tributary’s health.
“These include the upgrade of Kimbolton’s wastewater treatment plant, and erosion control planting primarily through
Horizons’ Sustainable Land Use Initiative in the upper reaches of the catchment.
Mr Thompson said it is also important to acknowledge strong community interest and involvement in restoration of the
Ōroua River.
“Ngāti Kauwhata representatives have consistently advocated for wastewater upgrades, and through their leadership of the
Ōroua Catchment Care Group are partnering with landowners in some really impressive clean-up work such as riparian
fencing and planting.”