The Byron Shire Local Government Area (LGA) is located in the Northern Rivers area of New South Wales. The area is affected by both riverine and flash flooding which can cause devastating over floor flooding in some locations and road closures due to flash flooding across low lying roads and crossings.
The Brunswick River is the main river system in the Byron LGA with a number of smaller tributaries such as Lacks Creek and Marshalls Creek feeding into it which can contribute to significant flooding in certain areas.
Mullumbimby
Mullumbimby, a town of around 4,000 people in the Brunswick Valley, Northern Rivers, NSW, is situated where the Brunswick River meets Mullumbimby Creek. Upstream, streams are confined to their channels, but downstream, extensive floodplains exist. Tidal influence can impact flood heights, with rising tides holding water back and causing levels to rise, while ebbing tides cause rapid falls. Flood height records have been kept since 1954, and the town has experienced several major floods throughout its history.
Billinudgel and Ocean Shores
Located in the Brunswick Valley, a flash flood catchment, Billinudgel has experienced major floods in 1987, 2003, 2005, 2012, and 2017, with the potential for even higher floods. The area's complex flood behaviour is due to multiple creeks and waterways, including Yelgun Creek in Tweed Shire and Lacks and Marshalls Creeks in Byron Shire. Lacks Creek flows through Middle Pocket, joining Marshalls Creek west of Billinudgel, which then flows through The Pocket and Billinudgel before joining the Brunswick River. Flooding can begin in Billinudgel at the western end of Wilfred Street, even below minor flood levels.
Downstream, the floodplain extends through Ocean Shores. Localised heavy rainfall can cause flash flooding and road closures, affecting only a few low-lying streets such as Balemo Drive, Rajah Road, and the Water Lily Park area, with water backing up around the Ocean Shores Golf Course.
South Golden Beach and New Brighton
South Golden Beach and New Brighton are also in a complex flood area due to the same creek systems. The floodplain spreads out through these areas, and localised heavy rainfall can cause flash flooding and road closures. South Golden Beach is protected by a levee to a height of 4.2m, but heavy rainfall can cause water to pond behind it. Low-lying areas of New Brighton are prone to flooding in moderate to major events.