Funding supports drive to tackle pest trees along Waihao River
A new community-driven initiative has received the backing of the local water zone committee to tackle the growing threat of invasive willows along the Waihao River.
The Waihao Wainono Catchment Community Group successfully applied for Lower Waitaki – South Coastal Canterbury Zone Committee funding to spray 400 hectares of crack willow, a pest plant that is choking the river, creating a significant flood risk and negatively impacting both water quality and quantity.
Clear fairways aid community resilience
Willows spread their roots into the riverbed, where their high water needs reduce flow and their rapidly decomposing leaves negatively affect water quality.
“There’s been a significant invasion of crack willow through the Waihao catchment over many years and it’s now getting to the stage where they’re completely blocking the river in some places,” Waihao Wainono Catchment Community Group chairman Roger Small said.
Having run the family farm in Willowbridge – 7km southeast of Waimate – for more than three decades, Roger has seen the havoc caused by crack willow in the district.
He recalls a flood in 1986 that uprooted large numbers of willows that caused a blockage and collapsed McCulloch's Bridge, resulting in a surge of water and significant flooding downstream.
“If we don’t do something, we can expect another disaster like that to happen again in a big weather event,” he says.
“It’s about building community resilience to these events and a big part of that is making sure we have clear fairways for the water to flow down.”
Community comes to the party in support of the project
The Waihao Wainono Catchment Community Group kicked off the project – which it estimates will require a 10-year commitment – in March and 36km of willows have already been sprayed in the upper reach of the river. Follow-up spraying will be undertaken to target regrowth and a phased approach to the willow removal will help keep the community safe.
“Four hundred hectares of willows is a lot of timber that can do some serious damage in a flood,” Roger said.
“It’s critical we don’t overload the system with dead trees. We’re looking to remove what we can, particularly in sections of the river where there’s vulnerable infrastructure.”
Volunteers from the Waihao Wainono Catchment Community Group working in the catchment
Roger said the catchment group is investigating wood chipping options to counterbalance the cost of removal, which far outweighs the spraying itself.
The catchment group, which began in 1999 as the Waihao-Wainono Water Users Group, has the support and backing of a lot of landowners in the catchment, who have come on board to bring the willow-removal project to fruition, contributing both time and funding.
“As a group that is staffed entirely through volunteers, any funding we get goes directly towards getting things done on the ground,” Roger said.
“With a project like this, however, it’s all about the maintenance so continued funding will enable us to make a really big difference.”
Water zone funding changing catchment outcomes
Every year we allocate funding for water zone committees to support community-led projects that aim to improve the environment and help meet Canterbury Water Management Strategy objectives.
The selected initiatives have to meet one or more goals in the zone committee’s Action Plan for 2021-24. We encourage any potential applicants to get in touch if they have a project that needs support and aligns with these goals.