Demands for CSIRO flood study

By Jonathon Howard

RAPIDLY EMERGING as the most hotly debated topic of 2023 is the health of the Tweed River and coastal creek catchments.

The Weekly has observed a rise in anxiety among residents who fear development on floodplains, siltation of the river which is leading to greater bottlenecks in waterways that could increase the impacts of future floods, and a lack of modern flood modelling.

The February 2022 flood was in many ways the straw that broke the camel’s back for farmers and business owners, who are now demanding greater flood research.

Farmers and local business owners have in fact long called for a comprehensive dredging program to remove excess siltation from the river, while many Tweed Coast residents are crying out for drainage improvements.

In a bid to bring these topics to the fore, a meeting took place at the Condong Bowling Club on Wednesday, April 5, calling for $2 million to engage the National Emergency Management Agency and CSIRO to carry out a modern flood study.

The open meeting was chaired by retired barrister David Freeman and attracted speakers including hydrologist Dr Daniel Spooner and Member for Lismore Janelle Saffin.

The meeting’s purpose was to gauge public support for Australia’s leading scientific agencies to carry out detailed hydrology and hydrodynamic flood modelling for the Tweed and coastal creek catchments.

The meeting called for the CSIRO to undertake full modelling of the current catchments and rivers system; the impacts of different weather events including future climate change scenarios; the impacts of built infrastructure on overland flooding; and the effects of different flood mitigation and adaptation options throughout the catchments.

Tweed Shire Council said it’s already on the case and has engaged a comprehensive flood modelling study with the results due to be released this year.

Council provided The Weekly with a range of updates and highlighted that the report and minutes of the latest Floodplain Management Committee held on Friday, March 3, will be discussed at this week’s Council meeting on Thursday, April 6.

In the report, Council said the committee discussed the CSIRO Northern Rivers Resilience Initiative.

Council’s report stated the committee resolved to support the continuation and completion of the Tweed Valley Flood Study Update and Expansion project, which is fully funded and well advanced, to provide a complete hydrologic/hydraulic flood model for the Tweed Valley flood- plain, to be completed in 2023, including public exhibition and public information sessions.

“The Council motion recommends to Council that the following request be forwarded to the CSIRO Northern Rivers Resilience Initiative (NRRI): that the NRRI provides a technical peer review of the draft Tweed Valley Flood Study Update and Expansion report, to allay community concerns that it is fit for purpose and provides the best available information on flood risk in the Tweed Valley,” Council’s report states.

“That the NRRI utilises the updated Tweed Valley flood model to be provided by Council, to test the potential effectiveness of dredging activities as a flood mitigation measure at various reaches of the Tweed River and its tributaries.

“The effect that the Pacific Motorway has on flood behaviour, including the Barneys Point Bridge approach, on the floodplain for all villages and determine any necessary measures to mitigate adverse impacts.”