Safeguarding our Stopbanks

Over the years people have built structures and planted trees outside their boundaries. We now need to remove some of the vegetation and structures to do this remediation work. As time’s gone on these non-approved structures and different types of vegetation have gradually advanced (encroached) beyond where they should have, which can impact the reliability of the stopbank.

These works are part of our overarching Safeguarding our Stopbanks project.

For the safety of residents who live in the area, recreational users of the trail and our contractors.

This first stage of work will take three to four weeks, weather dependant.

Stopbanks are generally raised earth embankments which provide protection against flood events from rivers and artificial waterways. Stopbanks form part of the wider flood protection system that may also include pump stations, floodwalls drains and flood gates.

Stopbanks are only as strong as their weakest link, and are vulnerable to damage from a number of different factors. Including damage caused by vegetation, or structures which shouldn’t be there. This is why it is so important we carry out maintenance works to ensure the stopbank will provide the level of protection needed.

These assets have been constructed to protect people, property and livelihoods from river flooding and drainage problems associated with extreme weather events.

There a several things, however these are the most common:

• Vegetation (particularly large trees with roots penetrating through the stopbank)
• Buildings/structures /fencing
• Excavation
• Large animals (like stock)
• Uncontrolled vehicle use

We want to keep our flood protection systems and stopbanks safe and in tip top shape. Unwanted structures, construction, animals, planting, trees and shrubs can weaken the stopbank and make it more likely to fail.

To give you some examples:

Plantings are a major problem on stopbanks.

Tree and shrub roots can cause a weakness in the stopbank by creating paths for water to flow through in a flood which can lead to rapid failure.

In extreme weather or storm events trees can become unstable and subject to windfall causing damage to the banks.

Read more information on stopbanks.

To manage the security and efficiency of our flood protection assets, Regional Council has Flood Protection and Drainage Bylaws.

These, provide us with a regulatory framework to protect and control flood protection and drainage structures (stopbanks, floodgates, pump stations etc) from misuse or damage across the region. Essentially, the Bylaws are a set of rules which protect, promote and maintain public health and safety, by ensuring any work on or near flood protection assets are done safely.

Anyone who wants to carry out work on or near flood protection assets needs to consider whether they will need a bylaw authority (written permission from Regional Council with certain conditions attached that describe what a landowner must do to ensure the flood protection structure is not damaged or compromised).

See if you might need authority from Regional Council.

View our Flood Protection and Drainage Bylaws page for more information.

In many areas across our region stopbanks are the last defense against floodwaters. They ensure the safety of thousands of people and help minimise risk to properties and livelihoods. Which is why it is so important we all work to make sure they are protected.

You can do:

• Use light vehicles only
• Maintain a healthy grass cover
• Be aware of the Floodway and Drainage Bylaw
• Control pests and noxious weeds
• Graze wisely in winter to prevent pugging

Bay of Plenty Regional Council Toi Moana maintains community flood projection assets (like stopbanks) throughout the Bay of Plenty.