Marshalls Creek flows into the Brunswick River approximately 1.2km from the mouth.
Flood behaviour in this area is complex due to the multitude of creeks and hydraulic connections between major floodplains, including the Mooball Creek catchment in Tweed Shire and the Yelgun and Marshalls Creek catchments in Byron Shire.
Marshalls catchment is linked to the Yelgun catchment at North Ocean Shores. There are culverts underneath Kallaroo Circuit linking the catchments. The catchment is bisected in a north-south direction by the Pacific Highway and the railway line.
Upstream of the Pacific Highway the catchment is predominantly agricultural and forested land. The area downstream of the Pacific Highway is significantly developed and this part of the catchment is a mixture of urban (including golf course) and forested areas. Townships within the Marshalls Creek catchment include Billinudgel, South Golden Beach, New Brighton and Ocean Shores.
Depending on the relative flood levels, flow between Mooball Creek and Marshalls Creek occurs in both directions and can change during a single flood event. Lacks Creek and Marshalls Creek converge upstream of Billinudgel. The floodplain significantly increases in size at the confluence of the creeks. The flow is then constrained by the railway line before passing through the Pacific Highway bridges. Downstream of the Pacific Highway the floodplain is also large, with water backing up into the Golf Course area.
Significant flood events occurred:
- May 1987 (this event is often referred to as “the Mothers Day Flood”)
- March 1974
- June 2005
- March 2017
A smaller event also occurred in January 2008.
North Byron Flood Study (adopted 2016)
This study combines the Marshalls, Simpsons and Brunswick Catchments using current flood modelling practices and the more detailed terrain modelling from a recent aerial laser survey. The study considers the urban areas of Mullumbimby, Brunswick Heads, Ocean Shores, New Brighton and South Golden Beach. Please see Brunswick River for further details on the North Byron Flood Study.
Tweed – Byron Coastal Creeks Flood Study (adopted 11 February 2010)
Byron and Tweed Councils jointly completed a flood study in 2009 which covers the Cudgen, Cudgera, Mooball, Yelgun and Marshalls Creeks. The Marshalls Creek catchment is the southern most catchment in this study and it covers an area of approximately 4200 hectares.
This study helped both Council’s better understand how the floodplain between the shires interacts across the shire boundary.
Goto to Flood Study for the main flood study document and the link below for the climate change assessment from this study.
Marshalls Creek Floodplain Management Plan (adopted November 1997)
This document details the flood risks that are present in the catchment and Council's plan to mitigate them. A previous Marshalls Creek Flood Study was finalised in November 1986.
North Byron Floodplain Risk Management Study and Plan
The next phase for Council is to prepare the North Byron Floodplain Risk Management Study and Plan. The North Byron Flood Study will be used for the preparation of this document. Until such time as the North Byron Floodplain Risk Management Study and Plan is adopted, the North Byron Flood Study (2016) and the Marshalls Creek Floodplain Management Plan (1997) should be considered for any flood planning matters.
The North Byron Floodplain Risk Management Study and Plan project is currently underway. Consultants WMA water have been engaged by Byron Shire Council for this project.