Maitai cleaner 'by summer'

22:14, Jul 17 2014
blue lines on Bridge St
CLEAR VIEW: Nelson City Council acting strategy and environment group manager Greg Carlyon, left, and Nelson City councillor Brian McGurk at the Maitai Dam spillway where a fish path is proposed.

The Maitai River revamp is under way with improvements in the waterway expected to be seen by this coming summer.

The Nelson City Council has put aside $400,000 over the next year to improve the river, working with community, recreational and conservation groups, the forestry industry and the Cawthron Institute.

The work will focus on three main areas - managing the Maitai Dam, reducing E coli in the urban parts of the river, and riparian planting.

Looking over the dam and its brackish waters yesterday, Greg Carlyon, who has been acting strategy and environment group manager for the council, said "it shouldn't be like this", while the council's planning and regulatory chairman Brian McGurk compared the colour to a pint of dark beer.

Coming from the Manawatu to work on the project, Carlyon said the Maitai was a fantastic river with a confined catchment and this combined with support of the community and the council made cleaning it up a "no brainer".

He expected there would be immediate improvements in the river.


"Come back in the middle of summer once the regime is running and you'll see and smell the difference," he said.

Plans to manage the dam involve limiting the damage from poor quality water being dumped into the clean south branch of the river - instead pumping quality dam water into the waterway.

The focus in the past has been on using the best H 2O from the dam for drinking water, pumping it along a pipeline to the treatment plant.

Carlyon said although it would cost more, drinking water could be treated to such a high standard nowadays it was logical to put quality substance from the dam into the river rather than the pipe.

Better timing will also be used to flush poor quality water from the dam out to sea - when flows are high or the river is in flood. "The city owns a great deal of the catchment so the council controls the land around it," said Carlyon, and eventually all forestry behind the dam would be converted back to native bush.

Adjustments will also be made to the dam's spillway so native fish and eels can crawl up and down it. The idea is to get fish passage throughout the river, so there will be no more washing of the car at the Almond Tree Ford, which is set to disappear.

Along the valley out towards the dam the aftermath of logging, in response to storm wind damage earlier this year, scars the steep hillsides. The council plans to work closely with forestry companies to ensure they carry out best practices - which many already do.

The golf course was also in discussion with the council about what fertiliser and treatments it uses, and septic tanks at households along the river would continue to be monitored.

Landowners with support from the council were working to keep livestock out of rivers - this was happening across the country, but Nelson was proactive in making sure it happened, said Carlyon.

Some parts of the project would happen quickly while others would need a longer commitment, but improvements in the river were "doable in a short period", he said.

Native species would be planted in spring, but these took time to become established, needing attention, resources and time.

Willow trees would be removed over time with native saplings taking their places in providing shade and keeping temperatures down in the river.

Managing E coli from leaks in the city's sewage pipeline would require ongoing work and monitoring.

The project will also reach into the Brook Valley with modelling about to be undertaken to find a way to make the Brook culvert more ecologically friendly for fish species while also offering flood protection.

The Nelson Mail