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Soft Engineering Solutions

Flood management strategies generally involve multiple engineering projects that can fall under one of two categories. Hard engineering projects are ones that involve the construction of artificial structures that, through a combination of science, technology and a bit of brute force, prevent a river from flooding. Soft engineering projects are the opposite.

What are Soft Engineering Projects?

These projects use natural resources and local people’s knowledge of the river to reduce the risk posed by a flood. Soft engineering projects focus more on reducing the impact of a flood rather than preventing one. The biggest advantage of soft engineering is cost. Soft engineering projects are significantly cheaper than hard engineering projects. They also have lower education & technology requirements so they can be implemented by local community groups and organisations.

Soft engineering projects focus more on reducing the impact of a flood rather than preventing one. The biggest advantage of soft engineering is cost. Soft engineering projects are significantly cheaper than hard engineering projects. They also have lower education & technology requirements so they can be implemented by local community groups and organisations. Soft engineering projects are more sustainable than their hard engineering counterparts. Soft engineering projects are low maintenance and low cost unlike hard engineering projects. In addition, they don’t disturb the natural processes and ecological systems in a river basin, instead choosing to integrate with them and in some cases improve them.

Soft engineering projects are more sustainable than their hard engineering counterparts. Soft engineering projects are low maintenance and low cost unlike hard engineering projects. In addition, they don’t disturb the natural processes and ecological systems in a river basin, instead choosing to integrate with them and in some cases improve them. With the demand for housing constantly increasing in Auckland and throughout New Zealand, the pressure on the management of our waterways is also increasing. Getting the balance can be difficult, however it is achievable. Could more soft engineering be part of the solution?

With the demand for housing constantly increasing in Auckland and throughout New Zealand, the pressure on the management of our waterways is also increasing. Getting the balance can be difficult, however it is achievable.

Could more soft engineering be part of the solution?

Soft engineering solutions have been around for some time, used extensively within Europe and USA and the results speak for themselves. However, the migration of these solutions does not appear to have occurred, short of the creation of stormwater wetlands. While we are seeing some innovative projects being delivered, a great example is Wairau Valley wetland and shared path, Clean Streams’ feels we are still missing opportunities. The project in Wairau Valley still involved the creation of a concrete wall for high storm surges. Yet there was an opportunity to use Brushwood Faggots instead of the concrete wall. Faggots provide a flexible solution to many scour problems and are also an excellent organic revetment for streams and river banks. They also provide additional habitat for a whole range of species.

While we are seeing some innovative projects being delivered, a great example is Wairau Valley wetland and shared path, Clean Streams’ feels we are still missing opportunities. The project in Wairau Valley still involved the creation of a concrete wall for high storm surges. Yet there was an opportunity to use Brushwood Faggots instead of the concrete wall. Faggots provide a flexible solution to many scour problems and are also an excellent organic revetment for streams and river banks. They also provide additional habitat for a whole range of species.

Of course, methodology will need to be adapted to suit New Zealand’s unique natural environment, however we are definitely able to undertake the challenge. The difficulty that we face is undertaking the risk and adapting these methodologies to suit our needs. We often like to stick to the tried and tested method even when there may be a solution that addresses the flood risk management issues and provides addition ecological benefits. Maybe the solution is to take a chance and try something new.wairau-valley-wetland-and-shared-path-now-open-2

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