One of the catchments that sheds a lot of silt into the Whanganui River is proving the slowest to take up a Horizons Regional Council erosion-reduction initiative.
The Ohura River, which flows into the Whanganui just south of Taumarunui, goes through soft hill country and is renowned for its bigsilt loads. Its catchment is one of the council's priorities for erosion control, using the whole-farm plans that are part of its Sustainable Land Use Initiative.
Only 1 per cent of the Whangamomona/Ohura catchment is covered by a whole-farm plan.
The other high-priority catchments in the wider Wanganui region are Whangaehu, Kai Iwi, Turakina, lower Whanganui and mid Rangitikei. The council aims to have 70 per cent of each of them covered by working farm plans.
At the moment the Whangaehu catchment is 44 per cent covered. Kai Iwi and Turakina are neck and neck with 25 and 24 per cent respectively, and the lower Whanganui is at 18 per cent.
The middle reaches of the Rangitikei River catchment are 24 per cent covered.
The Sustainable Land Use Initiative is about five years old. Many more farms were to be covered, Horizons' group manager environmental management Craig Mitchell said, and farmers were still coming forward.
"We've still got uptake and desire to come and talk to us," he said.
The plans consider farming viability - how to make full use of the best country and prevent erosion on the worst by retirement, tree planting and pest control.
To have any effect, they need to be followed.
"If we don't implement anything, we are busy fools."
Mr Mitchell said 85 per cent of farmers with plans were following at least some part of them.
"It could be anything from planting 200 poplar poles to putting in 1300ha of commercial forestry."
If half of the land area in those catchments was being farmed according to the plans then water quality would improve by 50 per cent, scientific evidence showed.
The Horizons region is 60 per cent hill country, and the council estimates 200,000ha has the potential for moderate to severe erosion. The Sustainable Land Use initiative started after the 2004 floods, when 200 million tonnes of silt was washed off the hills.
The plans aim to reduce erosion in the hills, reduce flooding downstream and improve water quality in rivers and streams.
