Bay of Plenty Regional Council: Help keep flood defences functioning this winter

Over-grazing on stopbanks and berms can lead to pugging and potential weakening of the flood defence structure.

With increased rainfall and weather events impacting the region, the Bay of Plenty Regional Council is reminding landowners living near the region’s flood defences to refresh themselves with the rules.

The Flood Protection and Drainage bylaws provide protection from damage and misuse to flood protection and drainage infrastructure assets (such as stopbanks, floodgates, drains and pump stations), which are managed by or under the control of the regional council.

“Flood defences are the first line of defence when it comes to reducing the impact of significant flooding,” rivers and drainage asset manager Kirsty Brown says.

“They have been built to increase productivity of land, and prevent damage, danger, and distress to the community from flooding, and problems associated with a lack of drainage, so it is crucial they function properly when needed.”

Brown says a common issue is stock overgrazing or “pugging” on stopbanks during periods of prolonged rainfall, as this can damage and weaken the stopbank.

“While light grazing of sheep and cows is allowed on stopbanks, it is not permissible to allow stock to damage them, and most farmers and lifestyle block owners know these rules.

“The reason is that when stopbanks become wet, stock can churn up the ground. This can create integrity risks for the stopbank through loss of grass cover - good grass cover is needed as it helps hold together the soil structure underneath. Loss of grass cover has been shown to be a contributing factor to stopbank failure in the past.”

Another issue is dumping rubbish on stopbanks or in drains, which can end up blocking the drain’s pump station and stop it from working effectively.

“Pumps are important for removing water out of drains as they become full, so if there was heavy rainfall and the pump wasn’t working, water levels in the drain would rise and potentially overflow, putting land and lives at risk,” Brown says.

Under the bylaws, these are not permitted activity and landowners can be liable for any damage to the flood defences.

“Our rivers and drainage team routinely monitor the condition of our flood defences, but we also welcome contact from members of the public who may suspect a problem. Our 24/7 Pollution Hotline (0800 884 883) is the best way to report any areas of concern.”

One of the regional council’s core roles is to make sure our flood defences are in good condition and manages more than $440 million of flood defence infrastructure on behalf of the community.

Find out more about flood protection in the region, include details of the Bylaws, on the Regional Council website: www.boprc.govt.nz/flood-defences.