Assessing the sensitivity of water resources...
URL: https://www.mdba.gov.au/sites/default/files/publications/assessing-the-sensitivity-of-water-resources-in-the-murray-darling-to-fire-and-climate-change.pdf
Authors: David Robertson, Hongxing Zheng, Durga Lal Shrestha and Francis Chiew
Date of publication: March 2024
Climate change projections indicate that conditions conducive to bushfires are expected to become worse in the future. Historically, fires have been shown to have short- and long-term impacts on catchment runoff and hence water availability. However, how the consequences of projected increases in the severity of fire weather impacted on projected runoff is poorly understood.
This study investigated the potential impacts of bushfires on water availability under a changing climate for more than 100 catchments in the Basin. Modelling methods were established that relate:
- climate data to fire weather,
- fire weather to the area of forest burnt and changes in leaf area index (LAI) due to bushfire,
- post-fire recovery of LAI, and finally,
- catchment runoff to LAI.
Runoff projections generated using these methods were compared to those generated using more traditional modelling methods that do not consider the effects of bushfires.
Key findings / recommendations:
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Under the investigated future climate scenario, fire weather is projected to be more severe, and frequency and extent of bushfires is projected to increase.
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Catchment average LAI is projected to decrease due to the increased frequency and extent of bushfires.
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The impact of projected increases in fire extent and severity on projected catchment runoff is expected to be relatively small because fires will still occur relatively infrequently, and any individual fire will only cover part of the catchment.
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Changes in future runoff are expected to be dominated by the direct impacts of changes in future rainfall and potential evaporation.
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