At least 20 per cent of vital vegetation cover along the banks of the Waitaki River has been illegally cleared, increasing the risk of severe flooding, say Environment Canterbury (ECan) river engineers. Timaru-based senior engineering officer Bruce Scarlett says the vegetation removal along the 65km stretch of river from Kurow to the river mouth has accelerated in recent years due to the boom in dairying.

“Basically it has been a land grab. Farmers have cleared the land to increase the pasture for their herds. But some are finding out almost too late that the impact on this during flooding, as happened in May this year, can be severe.”

The trees and vegetation are growing in the buffer zone that lies between the established river channels and existing farm land. Averaging about 250 metres wide, it constitutes about 3000ha in all. Bruce Scarlett estimates about 600ha of this has been lost over the past five to 10 years as farmers have cleared trees and vegetation to create more pasture.

This land is either privately owned allowing land ownership into the river channel or the property of either the Department of Conservation or Land Information New Zealand. But there is legal protection for trees in the buffer zone, even if it is planted on private land.

“The result of this clearance is that when the Waitaki floods, there is nothing to stop the water flowing back into former channels which are often now part of long-established farm land. By clearing the buffer zone, farmers are not only increasing the risk of severe flood damage on their own properties but also endangering their neighbours’ land.”

Valuable riparian vegetation, which are habitats for wildlife and important in the overall ecology of one of New Zealand’s most important salmon rivers, has also been destroyed.
Since the beginning of this year ECan has been approaching farmers offering to replant the buffer zones. In some cases they have been received very positively, Bruce Scarlett says.

“Some land-owners are new to the district and had no idea of what damage had been done by previous owners. They’ve been only too pleased to see us.” However not all farmers are receptive.
“We are still concerned that other farmers, who are either unaware of the potential increased flood risk or who are gambling on increased production outweighing any possible future damage, are still clearing the river buffer zone,” Bruce Scarlett says.

One measure ECan is now promoting to enable possible successful prosecutions for this in future is by defining more accurately the buffer zones and the actual river boundaries. This is being carried out in consultation with the Lower Waitaki River Ratepayers Liaison Committee. Similar projects are planned for other Canterbury rivers.

“The Waitaki however, is the most seriously affected of all our rivers. It’s becoming increasingly urgent that we take action,” says Bruce Scarlett.

In the past 18 months, ECan’s southern enforcement team has dealt with four formal complaints involving vegetation removal in this area, with possibly more to come.
Willow pole planting is occurring at some places where ECan engineering staff have been able to gain access.

For further information: Bruce Scarlett, ECan Senior Engineering Officer Southern area, 027 223-4030.