Source: Franklin County News
Farmers who have spent five years cleaning up the Mangatawhiri River fear the poor state of the remaining wetland at the mouth of the river could undermine continued funding of their efforts.
That 200ha wetland was once a flax and mānuka swamp, but it is now overgrown with grey willows, crack willows and other exotic wetland species, ccording to Matthew Dean, one of the driving forces of the Mangatāwhiri Catchment Care Group.
“It is also home to tens of thousands of mud-dwelling Japanese koi carp that stir up river bed sediment and thousands of Canadian geese that contaminate the water with their droppings.”
Despite the work of the catchment care group, the Mangatāwhiri River was still discoloured where it ran under the State Highway 1 bridge and joined the Waikato River, because it went through this poorly functioning wetland, Dean said.
That is “our one disappointment, and it is a big one”, he said.
He thinks the river will always be discoloured after flowing through the wetland “no matter what we do as farmers” upstream.
“We worry that the Waikato River Authority will be discouraged by this and stop funding our project when we seek its renewal.”
The river clean-up project has been going for five years and the farmers believe there is still plenty to do, but river authority-funded programmes only last five years and the group is due to apply for approval to have their project extended.
The Mangatāwhiri River Catchment Care Group began in 2016 with an investigation into why the river looked so discoloured at the old State Highway 1 bridge - an area of historical significance not far from the old Queen's Redbout at Pōkeno, where the invasion of Waikato startedin 1863.
A report published in 2017 showed that dairy farmers in the catchment - in spite of having spent millions of dollars on bridges, effluent ponds and effluent irrigation systems - had not achieved any visual improvement to the water quality at the SH1 bridge.
A meeting of stakeholders decided that farmers should stabilise eroding river banks and use fencing to exclude livestock from accessing the river. These works have been carried out during the past five years by farmers who pay the full cost up front, but get refunded 50% by the Waikato River Authority once the work has been completed successfully.
The Waikato Regional Council also provides technical support when needed.
From then on, farmers pay the full cost of ongoing maintenance.
The Mangatāwhiri River is about 30km long. The catchment has significant economic, social and natural heritage values and sites of cultural and historic importance for both tangata whenua and Pākehā.
One of Auckland's main water supply reservoirs lies in its native forest-covered headwaters. It then flows through highly productive alluvial silt and peat flood plains used for dairy farming, cropping, dry stock farming and lifestyle blocks.
The members of the catchment group who have helped make the changes include Dorothy and Hein Kroof, Jamie Lyons, Tim Detmar and Adam Liversedge from the Dilworth Trust. Environmentalists who have given technical and financial support include Matt Noble, Alice Trevelyn, Petra Specht and Russel Powell from Waikato Regional Council. Michelle Hodges from Waikato River Authority.
Merrin Whatley (PhD) fresh water ecologist helped motivate the group at the start and Dilworth school staff and pupils have also contributed at planting and working bees, as have Fonterra staff.
"We worry that the Waikato River Authority will be discouraged by this and stop funding our project when we seek its renewal."
Matthew Dean, Mangatāwhiri Catchment Care Group
Rock groynes protect an eroding bank and enhance fish habitat on the Mangatāwhiri River, with poplar poles also planted.