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Farmers & lifestylers
Image: BOPRC
Care > Farmers & lifestylers
Riparian management, which is the protection and care of banks or margins of waterways, is of vital importance in the Ōhiwa Harbour catchment. Erosion of stream and river banks can cause sediment and nutrients to enter the Harbour, affecting its water quality, shellfish beds and bird habitats.
Landowners, particularly farmers, are key to protecting waterways and biodiversity. Many are actively involved in looking after their land to protect the harbour. A lot has already been achieved and the work continues in the hills and on the flats behind the harbour.
The sediment issue
One of the biggest issues for the Ōhiwa Harbour is sediment flowing into the harbour from tributary streams and slowly but surely filling it up. The resulting fine mud also impacts on marine life in the harbour. Monitoring during a rain event in January 2021 found about about 225 tonnes of sediment/hr flowing down the Nukuhou River, the main Ōhiwa tributary.
Before the arrival of humans, extensive native forest would have protected the land and wetlands in the lower reaches of streams. It would have trapped much of the sediment before it reached the harbour. The clearance of the forests and draining of wetlands for agriculture sped up the erosion of the hills and stream banks. Nutrients and bacteria from livestock farming leaching into streams also need to be reduced.
This map (BOPRC 2013) shows the current types of land cover and land use in the Ōhiwa Harbour catchment.
Most of the land in the catchment is used for pastoral farming: dairying on the gentler land with sheep and beef on the steeper land.
Today, most farmers are well aware of the water quality issues and their role in trying to improve it and thereby the health of the harbour and are working hard to improve the way they farm.
What farmers are doing about it
In the Ōhiwa/Nukuhou catchment a group of farmers has been exercising what Margaret and Michael Kirk of Fairview Farm call their 'duty of care' for the land since the mid-1990s, considering the effects of their practices on the waterways that flow into Ōhiwa Harbour. When Norm Craig noticed the deteriorating water quality in local streams back in 1995, he contacted the Bay of Plenty Regional Council. This began a co-operative relationship that led to the retiring of 10 kilometres of stream edges from cattle grazing and replanting it to filter farm run-off and reduce stream-bank erosion. As a result, multiple wetlands for silt capture and beautification were created.
Farmers in the catchment have been fencing their streams and planting the banks wherever possible. Trees are being planted on steeper slopes to help prevent erosion and some areas are being retired from livestock altogether and planted either in natives or production trees. Remnants of native forests are being fenced to prevent damage by stock and protect their biodiversity.
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In 2011, the final three kilometres of fencing were added to protect all 56 kilometres of the Ōhiwa Harbour margins from access by stock.
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In 2015 the Nukuhou River won the Morgan Foundation Award for the 'Most Improved River' in the Bay of Plenty in terms of improved nitrogen levels. Watch this LAWA River of the month video about this success story.
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By 2018, 84% of all streams in the catchment were protected from access by stock.
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In 2020/21 alone 34 km of stream fencing was completed and 13,570 plants were planted.
Ōhiwa/Nukuhou Catchment Group
From about 2012 Nukuhou farmers including Norm Craig and the Kirk’s started working together as a small, informal group. They are now known as the Ōhiwa/Nukuhou Catchment Group. The group currently has 11 members and regularly gets together to discuss their work. They organise workshops and field days some of which are open to the wider public.
Contact: Frances van Alphen, Bay of Plenty Catchments Groups Coordinator, NZ Landcare Trust/Ngā Matapopore Whenua, Email: frances.vanalphen@landcare.org.nz
The Bay of Plenty Regional Council, among other organisations, works alongside these landowners and assists them with advice, planning and grant funding. It is a long term project with much still to be done.
