Recalling the establishment of the Pomahaka Water Care Group in 2014 at the recent South Island Dairy Event, West Otago farmer Lloyd McCall says the Otago Regional Council and Landcare Trust weren’t going to improve the river’s water quality.
“It’s got to be by farmers,” McCall says.
“You couldn’t fix it by rules.”
In about 2012 the council identified issues with nitrate and E coli levels, especially in the lower reaches, which prompted the Landcare Trust to get all stakeholders together to try to address the problem.
The Pomahaka flows from the Old Man Range to the Clutha River, fed by a 2020 square kilometre catchment and through 304 farms.
In most cases farmers were ignorant of their impact on the ecological and biodiversity values on their farms.
McCall recalls Conservation Department staff visiting his farm and showing him native galaxiid fish in waterways.
He and five other farmers met to discuss the water quality problem and came up with a plan and established the Pomahaka Water Care Group.
At its peak the group had 160 members.
Its aim is for the river to have the highest-quality water so future generations can enjoy it as this generation has and that meant a whole of catchment approach because all farms can affect water quality.
But that did not preclude enabling profitable and sustainable agriculture.
The group’s plan involved testing water samples at various points along the river’s 80km to define the extent of the issue and the problem spots.
So 28 sites are sampled four times a year which also lets farmers relate to how their activities and management affect the water.
“You haven’t got a problem until you know you have got a problem.”
The group started raising awareness and launched a regular media campaign promoting farm management steps to reduce water degradation, such as ways to prevent sediment runoff.
“It is all about taking ownership.”
That includes highlighting excellent as well as poor farm practices while showing interested groups such as scientists and academics what farmers are doing.
Farmers are encouraged to confront non-compliers and the group has members prepared to approach those not following best practice.
Riparian planting has been significant for farmers and to ensure they have enough trees and shrubs the group has established its own native nursery with 22,000 plants ready to be sent to farmers.
Further work includes crop leaching and infiltration rate trials and more work on wetland traps.
McCall says improvement has not been as desired for phosphorus but other nutrients are trending positively.
Alister Body farms sheep and deer and grazes dairy cows on 380ha near Tapanui. His farm has six main discharge points into the river. The quality of some was fine but others not so.
Water testing showed what had to be done but his main focus was minimising the movement of sediment over his land after rain, the main source of phosphorus and E coli.
He has also fenced all but 100m of his farm’s 3.5km river frontage and takes care managing areas where discharge or critical source is not great.
That means refencing his deer unit to reduce or minimise the impact of tracking and wallows, the selection of paddocks for winter cropping and the class of stock being run in steep paddocks.
Body has also changed his cultivation methods, avoiding critical source areas and establishing sediment traps and containment areas.
That involves slowing runoff or running it into traps to recover sediment.
He has built a network of multiple traps or wetlands in several paddocks into which runoff is channeled to collect sediment.
Body says they must be cleaned out and he is soil-testing the sediment to see if it has any nutrient value.