Urgent action needed on Napier's urban waterways to prevent 'point of no return'

HBRC and NCC are searching for answers to prevent Napier's urban waterways reaching an "ecological point of no return". Photo / Warren Buckland

Two Hawke's Bay councils are searching for answers to prevent Napier's urban waterways reaching an "ecological point of no return".

Hawke's Bay Regional Council and Napier City Council are gathering data on the current state of Napier's urban waterways, including pumped and gravity waterways discharging into the Ahuriri Estuary.

The recent survey revealed extremely high levels of phosphorous, nitrogen and very high levels of faecal coliforms and zinc, with "substantial work" needed to improve water quality.

A recent HBRC agenda authored by HBRC group manager asset management Chris Dolley highlighted an "urgent need to implement waterway treatment", while continued degradation of the Ahuriri estuary "could result in the system reaching an ecological point of no return".

Monthly monitoring of 21 sites has been undertaken over the past year, with all eight waterways recording average nitrogen and phosphorous levels well over the upper guidelines.

The "County Drain" waterway has the worst water quality, with the average amount of phosphorous in the drain 125 times higher than the upper guideline.

The 'County Drain' waterway has the worst water quality, with the average amount of phosphorous in the drain 125 times higher than the upper guideline. Photo / Warren Buckland

Average nitrogen readings in the County Drain are 25 times higher than the upper guidelines, while of the eight waterways monitored, all but one exceeded the upper guideline for average zinc levels.

The Taipo stream, which flows through Taradale, Greenmeadows and Tamatea, has an average faecal coliform reading more than twice the upper guideline.

Dolley said understanding waterways properly is imperative to avoid the unnecessary risk of implementing a treatment option which may not be appropriate or an efficient use of funds.

"The associated risk of implementing an inappropriate surface water treatment option prior to understanding the nature of the feeding urban waterways is daunting," he said.

The $600,000 research project, which is estimated to end in 2022, will be jointly funded by the two councils.

While all councillors agreed to receive the report at a council meeting on Wednesday, Jerf van Beek said if it were a farming report, there would be "serious outcry" from fellow councillors.

"To me, it's not fair - this is very serious. These are urban streets that are making a lot of mess."

Councillor Rick Barker also questioned why some Napier drains had been left off the list.

"I had cause to go to the Tyne St drain and I was afraid for my health - and I was only about five metres away," he said.

HBRC Māori partnerships group manager Pieri Munro said it had been excluded from the project because Napier has 100 per cent responsibility for that catchment.

Forest & Bird regional conservation manager Tom Kay said 99 per cent of New Zealand's rivers in urban catchments are polluted with nutrients and sediment.

"Pollution has pushed urban waterways across Aotearoa to breaking point.

"The Ahuriri Estuary has been encroached upon by industrial development, smothered with pollution from the city, and used as an outlet for wastewater and stormwater for decades."

Kay said the estuary must be protected and restored, with hopes of making it Napier's equivalent of Wellington's Zealandia.

The next stage of the project will analyse the data using an expert consultant to develop a capital improvement programme, determine which waterways should be prioritised and look into treatment options.

NCC infrastructure services director Jon Kingsford said part of the external consultants review will look at which contaminants can be treated together and what mechanisms can be used to remove contaminants.

"Ideally, that'll inform us where we might install treatment or removal devices," he said.

Dolley said anybody living and working in Napier can play their part in healing the estuary by making sure only rain drains into the stormwater drains.

"As a lot of Napier is low lying and flat, any excess rain water goes into the stormwater pipes – the network that protects homes and streets from flooding and which flushes out to the Ahuriri Estuary," he said.

"Pollutants can be very toxic to aquatic life in the waterways and often increase algae and bugs in the water, negatively affecting ecosystems and people."

Kay said strong public mandate and pressure on HBRC, NCC and industries is needed to make change.

"Only with strong rules and a strong public mandate will we start to move away from the archaic systems we currently have – where stormwater flows untreated, and wastewater and industrial waste often overflow, into the estuary."