Stock damage to stopbanks puts community at risk

We’re asking Canterbury landowners to keep stock well clear of stopbanks in wet winter conditions, when soils are soft and damage can happen quickly.

When stock access stopbanks, especially when it’s wet, they can create ruts and strip grass cover through trampling and overgrazing. This weakens the structure and reduces its ability to hold back floodwater, increasing the risk of erosion or failure during high river flows.

While some light grazing of sheep can be appropriate in dry conditions, we encourage landowners to keep stopbanks free of all stock through winter or whenever conditions are wet.

“These structures are designed to protect lives, property and livelihoods, and even minor stock damage can seriously undermine that protection,” says Rivers Manager David Aires.

“It’s crucial stopbanks can do the job they are designed to do.”

Avoid any activity that can damage a stopbank

It’s not just a rural message. Some stopbanks run through urban areas and protect large communities. Keeping them strong is a shared responsibility.

Everyday activities can cause damage, even when it’s not obvious. Driving vehicles, riding trail bikes, digging, building structures or planting vegetation can all weaken a stopbank and increase the risk of failure during a flood.

Disturbing the surface or changing the shape of a stopbank can create weak spots that allow water to enter and erode the structure.

Why it matters

Stopbanks are one of the most important tools in our flood protection network. We manage and maintain more than 600 kilometres of stopbanks across the region.

They are only as strong as their weakest link and are vulnerable to damage from a range of sources. Under the Flood Protection and Drainage Bylaw, landowners can be held responsible for damage and may be required to pay for repairs.

What to do if you see damaged stopbanks

We rely on early reporting because even minor damage can threaten the safety of thousands of people and the billions of dollars’ worth of property these stopbanks protect.