Tweed Valley Flood Study update and expansion

Tweed Valley Flood Study

Recent advances in the hydrology field and new flood records from March 2017 provides a good opportunity to improve our understanding of flood behaviour in the valley.

The flood study will help define flooding behaviour under current and future climate conditions and become the basis of flood planning in the Tweed.

The updated flood study will include the upper parts of the valley, including villages of Tyalgum, Chillingham, Uki and the surrounding rural areas for the first time.

During April and May 2021, residents responded to Council’s call to share their personal experiences and knowledge to better understand past flood events across the Tweed. Valuable information gained from this community consultation is being used to calibrate and validate the flood model.

The update and expansion will include:

  • model calibration and validation – review flood model based on historic events gathered from the community consultation, model flooding events by applying a range of probability based on flood magnitude in models, reporting and data provision
  • hydrologic analysis – review and extend existing model, flood frequency analysis, review rating curve, develop design hydrographs
  • modelling of existing scenarios – model design events, coastal interaction, blockage assessment
  • post processing of model outputs – flood hazard, flood function, high/low flow categorisation, flood emergency response classifications, mapping.

This project is funded under the NSW Government Floodplain Management Program.

Once completed, a draft of the Study will be placed on public exhibition for further community feedback. At this point, this is expected to occur in mid-2022.

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