There are two main objectives of clearing pest plant vegetation from river channels:

1. The main objective, is to maintain a river channel free from obstruction to efficiently convey flood flows, thus relieving erosion potential on the banks and minimising the risk of out-of-bank flood flows.

2. Clearing pest plant vegetation increases habitat area for river nesting birds.

GWRC has been looking into using an aerial spray method as a tool to manage pest-plant vegetation (mainly yellow lupine, tree Lucerne, broom) in the river channels, as opposed to the current method of knocking down pest plant vegetation with a bulldozer. Aerial spraying could be a cost effective alternative to the dozer method and environmental matters can be managed accordingly.

The main concerns are:

• Can the environmental issues really be managed appropriately?

• Is aerial spray really a cost effective option given the challenge and cost that will come with responsible management and consent monitoring?

What do you think? We'd love to hear your thoughts on this issue.