Proposed Interim Flood Planning Levels

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At the October 2023 Council meeting, it was resolved to exhibit the interim Flood Planning Levels proposed to replace current Flood Planning Levels.

The proposed Flood Planning Levels are informed by the peak flood depths across the Clarence Valley floodplain during a predicted 1% annual exceedance probability (AEP) flood event that includes mid-range climate change considerations, as indicated by the Lower Clarence Flood Model Update 2022 (see image below). An additional 500mm ‘freeboard’ is added to this flood event to determine the proposed interim Flood Planning Levels.

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It is proposed new homes or residential development with habitable rooms will be required to be built above this Flood Planning Level.

"Generally, the proposed Flood Planning Levels increase in all cases, more in Grafton and surrounds, and lesser in the Lower Clarence," Clarence Valley Council Manager Development and Land Use Planning Murray Lane said.

"This is because the proposed Flood Planning Levels include greater climate change assumptions than the current 2013 Flood Model. The 2022 Flood Model includes up-to-date assumptions about sea level rise and increases in rainfall and runoff associated with climate change.

"Including climate change in Flood Planning Levels is best practice and must be considered, as required by the NSW Government’s current flood planning policy and guidelines.

"The proposed interim Flood Planning Levels do not affect the use of existing homes or buildings, and will only apply to new development where habitable rooms are proposed."

Why is an 'interim' Flood Planning Level proposed?

Council has a responsibility to quickly incorporate the most up-to-date flood planning information from the 2022 Flood Model into Council's planning controls. Due to recent changes by the NSW Department of Planning and Environment to the standardised Local Environmental Plan which affects how Flood Planning Levels are determined, Council has commenced preparation of a new Floodplain Risk Management Study and Plan which is expected to take 18-24 months. The proposed interim Flood Planning Levels, if adopted, will be in effect until a new Floodplain Risk Management Plan is adopted.

Your can view the interim Flood Planning Levels for individual properties on Council's Online Mapping System. If you require any further assistance please contact Council on 02 6643 0200.

The Lower Clarence Flood Model Update 2022, including interim Flood Planning Levels proposed, animations and other details are available here: