Lismore is one of the most flood prone urban centres in Australia and due to its location, has a long history of damaging floods.
The catchment above Lismore is a very complex one and flooding is influenced by catchment conditions, distribution (where rain falls) and intensity of rainfall. There are several major creeks that feed into Wilsons River and Leycester Creek which join at Lismore. Major flooding can result from water rises in either the Wilsons River or Leycester Creek and consequently can be described as a Wilsons or a Leycester Creek flood. Significant flooding also occurs when both are flooding at once. Historically, most floods occur when Leycester Creek is the more dominant stream.
The local information page provides valuable resources for your Local Government Area (LGA). You can explore flood information for your local river catchment through Local Flood Insights, access local flood plans and guides, and connect with local councils and NSW SES units.
Lismore CBD and The Basin
A levee was built in 2005 to protect the CBD in a 1:10 event and it has protected the town many times since. However in 2017, floodwater reached 11.59m and overtopped the levee wall for the first time since the levee was built. Businesses were inundated with floodwater.
The Lismore CBD has the added risk of being affected by flash flooding in the CBD Basin. Very heavy rain can cause flash flooding in the CBD Basin without riverine flooding occurring.
North and South Lismore
North Lismore is the first sector to flood (from 4.3m on Rowing Club Gauge). This is a low lying area and is not protected by any levee.
Levees have been built in South Lismore and protect the area from moderate floods. However, if major flooding occurs, this levee may also be overtopped with substantial flooding.
Both North and South Lismore may be affected by Flood Slope.
Flood slope means that water levels upstream from the Rowing Club Gauge will be higher than the Rowing Club Gauge measurement. Residents and property owners in locations upstream from the Rowing Club Gauge must allow for higher than expected levels.
Many anecdotal conversations post 2017 floods showed that people in North and South Lismore did not allow for the flood slope when preparing their homes for flooding and didn’t raise their household items high enough. As each flood is different, and every flood slope will be different.