Floodplain Management plans, flood studies and animations

The NSW Flood Risk Management Process has four stages – data collection, flood study, flood risk management study and flood risk management plan.

Flood Studies 

Lower Clarence Flood Study Update 2022

In June 2023 Council resolved to adopt an updated flood study review, subject to an independent peer review and validation confirming the modelling methodology. The independent peer review and validation was completed in September 2023, with all the peer reviewer’s recommendations being incorporated into the final flood study review. The review used a finer modelling grid that previous models, incorporated the second Grafton Bridge, Pacific Motorway and West Yamba filling into the model and was validated against the January 2013, March 2021 and March 2022 flood events. The model has considered climate change with 2123 flood levels incorporating predicted increased rainfall and sea level rise under two Shared Socioeconomic Pathways (SSP) - SSP2 and SSP5. Council has adopted the SSP2 flood levels.



Glenreagh Flood Study

In 2014 Council adopted the Glenreagh Floodplain Risk Plan and in May 2018 Council adopted the Glenreagh Floodplain Risk Management Study and Plan.The Council resolution (14.050/18) adopting the study and plan split Action P5.1 into two actions, with the installation of a new automatic flood gauge at the Glenreagh Bridge identified with a capital cost of $15,000 and an annual maintenance cost of $3,000, and schedule implementation of management actions as part of the Council’s future Delivery Program and Operational Plans.An addenda page (#2) was added to the Final Draft document adopted by Council outlining the change by resolution.

Glenreagh Flood Study Update - Climate Change Assessment Report 2025

Council resolved at its March 2026 Council Meeting (2016.108), to adopt the Glenreagh Flood Study Update - Climate Change Assessment Report 2025 (Flood Study Update 2025). This is an update to the current adopted Glenreagh Flood Study 2013. The update was required to align with the current NSW Flood Risk Management Manual 2023 which now requires climate change scenarios to be incorporated into Council’s flood planning.

The climate change scenario selected for the Glenreagh Flood Study Update 2025 is the Representative Concentration Pathways (RCP) of 4.5, being the mid range scenario with a modelling timeframe to 2090. Therefore, the updated Defined Flood Event for the Orara River at Glenreagh is the 1% Annual Exceedance Probability (AEP) 2090 Climate Change (RCP 4.5).

Wooli Flood Study

At its September 2023 meeting council resolved to adopt the Wooli River Flood Study and to exhibit the draft Wooli Floodplain Risk Management Study and Plan, with the Study and Plan to be adopted if there were no submissions changing their intent. No submissions were received during the public exhibition which changed the intent of the Wooli Floodplain Risk Management Study and Plan, and at its meeting of 18 March 2024 Council’s Floodplain Risk Management Committee endorsed the Flood Study and Plan as exhibited.

 
Floodplain Risk Management Plans

Grafton and Lower Clarence Floodplain Risk Management Plan

Council adopted the Grafton and Lower Clarence Floodplain Risk Management Plan (FRMP) in 2007, with a review of flood mitigation measures and management for Brushgrove considered by Council in 2013. The Grafton and Lower Clarence FRMP was updated to identify the revised flood management actions for Brushgrove.

In June 2023 Council resolved that, following adoption of the Lower Clarence Flood Study Update 2022, a consolidated Lower Clarence FRMP incorporating all the existing FRMPs be developed.

Alipou Creek Floodplain Risk Management Plan

The Alipou Creek Floodplain Risk Management Plan (FRMP) was adopted by Council in 2007.

In June 2023 Council resolved that, following adoption of the Lower Clarence Flood Study Update 2022, a consolidated Lower Clarence FRMP incorporating all the existing FRMPs be developed.

Iluka Floodplain Risk Management Plan

The Iluka Floodplain Risk Management Plan (FRMP) was adopted by Council in 2007.

In June 2023 Council resolved that, following adoption of the Lower Clarence Flood Study Update 2022, a consolidated Lower Clarence FRMP incorporating all the existing FRMPs be developed.

Yamba Floodplain Risk Management Plan

The Yamba Floodplain Risk Management Plan (FRMP) was adopted by Council in 2009.

In June 2023 Council resolved that, following adoption of the Lower Clarence Flood Study Update 2022, a consolidated Lower Clarence FRMP incorporating all the existing FRMPs be developed.

Wooli River Floodplain Risk Management Plan

At its September 2023 meeting council resolved to adopt the Wooli River Flood Study and to exhibit the draft Wooli Floodplain Risk Management Study and Plan, with the Study and Plan to be adopted if there were no submissions changing their intent.  No submissions were received during the public exhibition which changed the intent of the Wooli Floodplain Risk Management Study and Plan, and at its meeting of 18 March 2024 Council’s Floodplain Risk Management Committee endorsed the Flood Study and Plan as exhibited.

Glenreagh Floodplain Risk Management Plan

In 2014 Council adopted the Glenreagh Floodplain Risk Plan and in May 2018 Council adopted the Glenreagh Floodplain Risk Management Study and Plan. The Council resolution (14.050/18) adopting the study and plan split Action P5.1 into two actions, with the installation of a new automatic flood gauge at the Glenreagh Bridge identified with a capital cost of $15,000 and an annual maintenance cost of $3,000, and schedule implementation of management actions as part of the Council’s future Delivery Program and Operational Plans. An addenda page (#2) was added to the Final Draft document adopted by Council outlining the change by resolution. 

 

Levee Overtopping Studies

Grafton and Maclean Levee Overtopping Study 2023

In April 2023 Council noted the Grafton and Maclean Levee Overtopping Study, 2023. Using the Flood Study Update 2022, the levee overtopping study outlines what is expected to occur if the Maclean or Grafton levees are overtopped by a flood. This information is used to assist the SES develop their response to a levee overtopping.

 

Floodplain Modelling Animations

The below animations have been produced by BMT WBM Australia. Clarence Valley Council gives no warranty, express or implied, as to the currency, accuracy and/or completeness of any information contained in the animations. It is not possible to accurately predict exact future flood levels for any location.

The design flood levels shown have been derived using the computer simulated model for 1%, 2%, 5%, 0.2% or Extreme ARI (Average Recurrence Interval) flood events. A qualified consultant and/or surveyor should be engaged to assess the potential impact of the relevant design flood level against the relevant ground or floor levels for any particular property before making any decision to purchase, sell or do anything on, at or to that property.

Whole Catchment Animations

1% Flood Event 

 

2% Flood Event 

 

5% Flood Event 


0.2% Flood Event


 

Extreme Flood Event

 

Grafton Area Animations

1% Flood Event


2% Flood Event


5% Flood Event


0.2% Flood Event


Extreme Flood Event 


Yamba Area Animations

1% Flood Event 



2% Flood Event 


5% Flood Event 


0.2% Flood Event 

 

Extreme Flood Event 



2022 Flood event

Whole catchment


Ulmarra 


Yamba


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