“This place was called Kokopu for a reason and it would be great to improve the water quality and remove the physical barriers to them returning,” he said.
The co-chair of the Mangere Catchment Group, formed in 2013, Kocich described himself “a little more green” than fellow farmers in the district.
But his ambition will need the cooperation of all stakeholders to improve the water quality in what was once known as the worst river in Northland.
Yet the short-run Mangere River west of Whangarei was named most-improved in Northland in the 2014 Rivers Awards and fourth-equal most-improved river nationally, behind three mainly urban waterways.
The award was based on a 14.5% compounded annual reduction in dissolved reactive phosphorus levels over a decade.
Because it takes years to bring about improvement in water quality, clearly the Northland Regional Council (NRC) and district landowners had put in place the means for improvement long before the catchment group was formed.
Mangere is one of NRC’s five priority catchments, formed in response to the National Policy Statement on Freshwater. It rises in the Pukenui Forest and the western hills of Whangarei and flows west, away from the nearby Whangarei Harbour and the eastern coast, draining the Matarau, Gumtown and Kokopu districts before discharging into the Wairua River and eventually into the Kaipara Harbour.
The NRC described it as a low-lying, sluggish tributary to the Wairua that flows through a mostly intensive agricultural catchment.
The catchment contains 19 dairy farms and numerous lifestyle blocks and orchards and the NRC recorded in its official catchment description in 2013 that 18 of the dairy farms had upgraded their effluent systems at least once, 11 more than once.
Nine farms with consents to discharge treated effluent to water throughout the year had installed land application systems and now only discharged during wet conditions.
The NRC said all water quality indicators at the Knight Road bridge monitoring site (just before the Mangere joins the Wairua) were either stable or improving, thanks to the farm dairy effluent (FDE) upgrades.
But water quality was still severely impacted and ongoing land management changes were required.
Unusually, accumulated nutrients, suspended sediments and bacterial loading were also measured at the most upstream site, above all the dairy farming and near the Pukenui Forest, indicating work needed in that part of the catchment.
Kocich said all members of the catchment group, and their Mangere stakeholders including farmers, residents, iwi and authorities, had been learning up until now.
“We are all on the same wavelength and now we will have to start making choices among the community expectations for the Mangere.
“Can we provide public access to the Mangere Falls, what will be our water quality targets and over what time period – those types of hard questions,” he said.
Water takes in the catchment for horticulture, pasture irrigation, livestock drinking and dairy washdowns might also need addressing. Allocation is considered high at more than 10,000 cubic metres a day.
The major issues for the Mangere remain low oxygenation and sedimentary loading, not nitrification or E. coli, which could also be as a result of the FDE upgrades.
Freshwater ecologists have said the return of banded kokopu to the upper reaches would need more riparian vegetation to provide shelter and reduce sedimentary run-off, and more water oxygenation through reduced water takes.
DairyNZ has provided some options for water monitoring and dairy recycling and its catchment engagement leader for Northland, Helen Moodie, is on-call to all dairy farmers.
Other dairy farmers in the catchment said they were pleased with the water quality improvements to date and welcomed the community collaboration effort through the catchment group.
Long-term sharemilker Ian Douglas, on the McKegg farm at Matarau, milked 400 cows at peak on 242ha with an FDE that was completely re-designed six years ago.
Douglas was asked by the McKeggs to design and organise the building of a weeping wall and large storage pond system with effluent water irrigation over about 25ha.
It also has three HerdHomes, from which liquid manure is taken by muck spreader to the maize cropping area once a year.
Much of the farm, including the FDE site, is flat and there is no consent to discharge into either of two creeks that eventually join the Mangere.
But the farm does have a consented lake for storing water and irrigating 30ha in dry summers.
“The streams are prone to drying up and we don’t crop the irrigation area, so there is minimal sedimentary run-off,” Douglas said.
His staff members take great care to apply both water and effluent on to soil conditions and with time periods that prevent run-off or ponding. Cows make good use of the HerdHomes for supplementary feeding and the minimisation of pugging in wet periods.
With more than 50 lifestyle neighbours, major ground-spraying operations have to be notified.
“Like most farmers, we are not intentionally trying to do anything bad in the environment and we are keen to get the credit for that approach.
“The catchment group is a good initiative and a good forum for discussion.
“The Mangere was starting from a poor position and under the watch of nearby Whangarei.”
In the most intensive dairying district, along the Mangapiu Stream aligned with Kokopu Block Road, dairy farmer Stephen Carter milked 460 cows at peak on 159ha effective.
“We never purposely polluted before, but now we are improving all the time,” he said.
Carter has extended the effluent spraying area to 30ha, using both a travelling irrigator and a pod system to include some hills and apply lower rates. All staff members contribute to a FDE management programme to record when and where things are done and suggest improvements.
“We have a consent to discharge into the Mangapiu but we don’t do it – I think the last time was about four years ago during a big storm.
“A contractor pumps out the oxidation ponds for the dairy and the wintering barns and we keep the water levels low to ensure we do not need to discharge.
“Little water intake areas have been fenced as a series of small sediment traps and we keep the cows off the paddocks in the worst wet times.”
Kocich has also made many improvements to land and FDE management, fencing the stream through the farm and swampy areas where sediment would be trapped.
The water-course had been stabilised with new riparian plantings replacing the broken-down willows and macrocarpas.
Maize silage was fed from February onwards before the afternoon milking, on a feedpad with a two-pond drainage system of its own.
The main FDE consisted of three large ponds with storage of 90 days and 150m of horizontal filtering through a manufactured wetland of poa aquatica before reaching the creek environs.
As with the other farmers spoken to, Kocich’s aim was never to use the discharge consent.
“The NRC has a strict monitoring system, being a visit to every farm every year without notification.
“That policy has pushed FDE improvements and farmers have responded, and we are now seeing the benefits in the Mangere River.”
Kocich is a former president of Northland Federated Farmers and director of the former Northland Dairy Co-operative.
He was also the inaugural judging co-ordinator for the Ballance Farm Environment Awards in Northland and served on the Farm Environment Awards Trust.
