Environment Waikato will begin clearing nuisance willow from the Wharekawa River this summer in response to community concerns over erosion and flooding in Wharekawa catchment.
A digger will be used to clear crack willow downstream of the SH25 bridge. Work is planned to start in late December and will continue into early January.
“Willow is currently choking the river, reducing its ability to carry flood waters and preventing sediment from being flushed through the system,” said Environment Waikato land management officer Emily O’Donnell.
“Our goals are to allow the water to flow freely, decreasing flood risks, and to improve water quality.”
Summer has been chosen to carry out the work because water flows are low and there is no spawning or migration of fish in the river.
Next winter the riverbanks will be stabilised using a combination of sterile Matsudana willow poles and native vegetation. The Matsudana poles are fast growing and have dense root systems that will hold the soil together until the slower growing natives become established. A sterile variety of the willow is being used to ensure it does not spread back into the river channels.
Ms O’Donnell said members of the Wharekawa community had noticed a decline in water quality in the Wharekawa harbour over the past 20 years.
“The community has approached us to look at how best to protect the catchment and enhance it for future generations to enjoy. A key concern for them is the amount of sediment entering the harbour, and landuse practices in the catchment. Among other things, they are worried about the impact of sediment on local shellfish beds and recreational fishing.”
In response, Environment Waikato encouraged the community to form a group to support and encourage others to protect the catchment. Through this group (the Wharekawa Catchment Care group) Environment Waikato is developing an integrated catchment management plan designed to provide information on the current state of the catchment and how it can be improved for the future. This will be completed over the coming year.
“In the mean time this willow removal project is a way to show the community what can be done and perhaps to inspire more landowners to get involved,” Ms O’Donnell said.