Whanganui's new urban wastewater treatment plant was completed in 2018.
Photo / Bevan Conley
Whanganui's new urban wastewater treatment plant was completed in 2018.
Photo / Bevan Conley
Preliminary results from a Whanganui District Council survey indicate that the majority of respondents oppose the Government's Three Waters Reforms and want the council to retain management of the district's water assets.
The council lost the opportunity to formally consult the community when it was announced last year the reformswould become mandatory and responsibility for Whanganui's water supply, wastewater, and stormwater will shift to a new authority comprised of 22 shareholding councils in 2024.
While the Government had estimated that 20 per cent of councils in New Zealand have failing water infrastructures, Whanganui District Council has invested heavily in maintaining its assets.
So what are Whanganui's water assets, what is their value, and what kind of shape are they in?
Whanganui District Council is responsible for the provision and management of five water supply systems: the Whanganui urban water supply scheme, and rural schemes at Fordell, Maxwell (Pākaraka), Mowhanau, and Westmere.
The systems are comprised of service lines, pipe networks, pump stations, treatment plants, and reservoirs.
According to the council's Water Supply Asset Management Plan 2021 the schemes were serving the population with 16,555 connections.
The assets consist of nine bores, five treatment plants, 28 reservoirs, 520km of pipelines, 17 pump stations, 2943 valves, 2122 hydrants, and 715 backflow preventers.
The gross replacement cost of the assets is $171.5m and a depreciated replacement cost of $90.9m.
The bore at Fordell is one of nine in the Whanganui water supply network.
Photo / Bevan Conley
Wastewater
The council's wastewater assets and services include the urban wastewater treatment plant on Airport Rd and two rural systems serving Marybank and Mowhanau.
The $38.9m urban plant began operating in 2018 after the previous 2007-built plant failed and had to be closed in 2013.
The failure led to an independent review, legal action, and lengthy debate around the council table over the cost of the new plant.
At the time of the Wastewater Asset Management Plan 2021, there were 15,024 service connections.
The wastewater assets consisted of 276km of pipes, 4,655 manholes, and 35 pump stations.
The assets were valued at a gross replacement cost of $338.7m and a depreciated replacement cost of $196.2m.
Until the late 1970s Whanganui had a combined drainage network that collected both wastewater and stormwater from streets and private properties.
In the decades since separate networks have been created across 92 per cent of the city.
Whanganui's stormwater network includes discharges to the Whanganui River, streams, pipe networks, drains, and ground soakage areas.
According to the 2021 Stormwater Asset Management Plan the urban stormwater network has 169km of pipeline, 3522 manholes, and 3133m of outfalls.
The Mowhanau network has 335m of pipeline, 11 manholes, and 8m of outfalls. The network at Marybank has 342m of pipeline, 12 manholes, and 18m of outfalls.
Whanganui has 15,159m of open drain waterways, 1902m of piped drain, and 12 waterways structures (bridges, culverts, stopbanks).
The assets were valued at a gross replacement cost of $189.8m and a depreciated replacement cost $134.5m.
There is particular concern about Whanganui's stormwater management.
Photo / Bevan Conley
Mayor Hamish McDouall said the transfer of stormwater management to the Three Waters entity is of particular concern for Whanganui because of Te Awa Tupua - The Whanganui River.
The Whanganui River Claims Settlement Bill passed in 2017 recognises Te Awa Tupua as an indivisible and living whole, comprising the Whanganui River from the mountains to the sea.
The settlement provided for the river's long-term protection and restoration by making it a person in the eyes of the law.
"Whanganui's stormwater is discharged into the river and we have not been given time to properly consult with iwi and hapu on the Three Waters reforms," McDouall said.
"We needed to consult with the whole community and the opportunity was taken away when the reforms became mandatory."
The Government has committed to "uphold existing Treaty Settlement arrangements, including through transition and the standing-up of new entities" however McDouall said the uniqueness of Te Awa Tupua warrants very specific consideration.
Whanganui District Council Infrastructure manager Mark Hughes.
Photo / Supplied
The council's general manager of infrastructure Mark Hughes said the stormwater networks had crucial links with the river, the environment, and other infrastructure.
"The advantage of retaining stormwater is that it has those links with Te Awa Tupua, water courses, wetlands, attenuation areas such as parks, and road drainage," he said.
"Traditionally the stormwater and sewer networks have been managed and co-ordinated by 'drainage teams'. The new entity will need to identify how this co-ordination will continue."
Hughes said seven water upgrade projects funded by the Government's $6.33m three waters stimulus and reform funding to the council in 2020 had been completed.
In 2021 the responsibility for New Zealand's drinking water regulation moved from the Ministry of Health to the new Crown entity Taumata Arowai. The regulator will not assume responsibility for wastewater and stormwater until 2024.
