Source: Environment Canterbury Regional Council
Work programme protects waterways and wetland health
Waterway management and wetland health is a primary focus of the work in the Ahuriri Catchment in the Upper Waitaki. The aim is to protect the ongoing health of Lake Benmore as well as identify and protect wetlands in the area.
“Wilding willows draw a huge amount of water, so where we have them invading wetlands and slow-flowing streams, they can reduce freshwater availability and degrade habitats,” said Jess Hishon-Knowles, senior land management advisor for the Mackenzie Basin and Upper Waitaki.
“That’s why it was important to be mindful of the issues at play and get control under way.”
Collaboration with landowners key
Targeted spraying work was done by helicopter over a single day in late summer, just as trees were beginning to turn in the dry conditions. Plans were developed in collaboration with landowners, focusing on early-stage wilding willow seedlings. By the end of the day, more than 270 hectares had been sprayed across seven farms.
“This was about targeting areas where wilding willows are a threat to biodiversity and water quality and supporting landowners who are already invested in improving the health of waterways,” said Hishon-Knowles.
“The timing aligned well with work already happening through the Wairepo Catchment Group and their restoration project around the Wairepo Ponds.”
The Wairepo Ponds are small man-made lakes joined to Lake Ruataniwha, a lake south of Twizel that forms part of the Waitaki hydroelectric scheme.
Willow control a balancing act
Willow control remains a balancing act for us, with some willow varieties used in a managed way for erosion and flood protection.
“Achieving the ideal outcome usually comes down to one simple principle—the right tree in the right place,” said Hishon-Knowles.
Vegetation clearance in wetlands is a permitted activity, however, there are regulations and best practice guidelines that need to be followed, especially for aerial spraying.
For any property owners in the Ahuriri and Upper Waitaki area looking to do this type of work, please contact Jess Hishon-Knowles, senior land management advisor.
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Retrieved: 3:29pm, Tue 10 Jun 2025
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