Structural flood mitigation

Structural flood mitigation is the construction or modification of physical structures in order to reduce the impact of flooding on individual properties or whole catchments (Government, 2018). The following are some examples.

Infrastructures: dams, levees, bridges and culverts

If we consider structural solutions, it’s important to understand the effectiveness of individual measures in terms of flood mitigation impact. For example, some works may reduce flooding to a large area by centimeters which can lead to a minimal benefit to a large number of homeowners that are less affected by the event and almost no benefit to those homeowners that are worst affected by the flood.

Maintenance of existing infrastructure

An important aspect is the ongoing maintenance to existing creeks and stormwater drainage systems. This is very important, because it allows to maintain the hydraulic performance of drains. The development and revision a regular maintenance schedule for areas subject to flood can provide significant benefit during seasonal rains. On the other hand, targeted clearing of creek systems doesn’t always help the reduction of the impact of large flood events, it helps in reducing the impact of smaller and more frequent floods.

Individual flood proofing measures

It’s also possible to keep flood waters out of the buildings and homes by installing solid fences, raising windows, sealing doors and limiting the sewage contamination with reflux valves. This can be done where the inundation caused by flood is low (nominally less than 700mm).

Improved traffic access

Another possibility is to improve the flood resilience of roads so that it provides a benefit to the residents affected by these events, by allowing them to escape floods and to access emergency service.