Floods in Hot Water?

Understanding Floodplain Changes in Australia's Murray-Darling Basin

The Murray-Darling Basin is vital for Australia's environment and economy. How are floods changing with climate? This study uses satellite data and models to find out.

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Explore the Basin

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Click on the map regions (North/South) or key sites (markers) to see specific details.

Murray-Darling Basin

Australia's largest river system, facing complex water challenges.

How We Track Floods Over Time

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Direct flood maps only go back 35 years. To look further back and into the future, we need a reliable clue, or proxy.

Finding: The best clue is the Maximum 30-Day Runoff ā€“ the highest amount of water flowing off the land over a 30-day period each year. It strongly correlates with observed flood extent.

More Frequent Floods Recently (If Only Climate Mattered)

Using our 'runoff proxy', how does the climate of the last 35 years compare to the last century?

Comparing flood likelihood: Recent climate conditions (Blue, 1988-2022) vs. Long-term history (Grey, 1900-2022). Higher lines mean more frequent floods for a given size. Especially noticeable in the South.

Note: This shows potential based on climate alone. Actual floods are also affected by dams and water use.

The Future Flood Puzzle

Climate change projects less overall water, but more intense downpours. What does this mean for floods?

Projected Flood Likelihood (Red, 2046-2075) vs. History (Grey, 1900-2022). The shaded red area shows the range of climate model projections.

Key Insight: Floods seem less affected than overall water decline! Rarer, bigger floods might stay similar or even increase (especially North), while smaller floods might decrease (especially South).

Zooming In: North vs. South & Key Sites

Changes aren't uniform. Click buttons below (or map areas) to see regional differences for a typical '1-in-20-year' flood event.

MDB Overall

Projected change in 1-in-20-year flood size: ~+5% (Median projection, but wide uncertainty)

Varied picture across the basin.

What Does This Mean?

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  • Complexity: Climate change isn't simple ā€“ less total water doesn't always mean fewer big floods. Intense rain matters.
  • Regional Differences: Solutions need to be local. North MDB faces different future flood risks than the South.
  • Adaptation is Key: Water managers need this info to plan environmental flows and manage flood risks effectively.
  • Proxy Power: The '30-day runoff' proxy helps bridge data gaps to understand long-term flood trends.