http://www.clw.csiro.au/publications/waterforahealthycountry/swsy/
Reported in 2010. Presentations and reports at the link above. There are three reports:
1. A summary that highlights possible shortfalls in 2030
2. A report on surface water supplies (rainfall and run-off from rain fall)
3. A report on ground water supplies (e.g. aquifers)
This post is a summary of the summary on surface water (rainfall)
It's going to rain less. The warmer it gets the less it rains. On average there will be 8% less rainfall and 25% less run-off. How bad it could get? Rainfall down 14% and runoff down 42% by 2030. Report does not go into what this will mean for agriculture, urban areas, policy etc.
Brief methodology
Forecast out to 2030, using three possible future climates: "wet extreme, median and dry extreme future climate". These were compared to "historical" (1975 - 2007) and "recent" (1997 - 2007) climate models.
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| Graphs of changes from SWSY-Summary-SurfaceWater.pdf |
It's going to get drier and the more the climate warms the drier it will be.
Rainfall declines in all three futures vs historical and recent. E.g. in "median" future "rainfall declines by an average of 8 percent and runoff by 25 percent relative to the historical climate.
In the future "streamflow" will decline by 800 gigalitres (GL) (for the median future) and by over 1400 GL under the dry extreme future climate. <How significant is that?>
Historically "the probability of rainfall exceeding 900 mm and runoff exceeding 130 mm in any one year is 20 percent. This probability reduces to 5 percent under the median future climate and to less than 3 percent in the dry"
Variability will increase substantially.
Days of low or no flow will increase.
Some numbers
Top section of table from the pdf. (Other rows, not copied, broke down results by geographical areas.) This table may be useful comparing for different scenarios and identifying just how bad it could get...rainfall down 14% and runoff down 42% by 2030.
In the future "streamflow" will decline by 800 gigalitres (GL) (for the median future) and by over 1400 GL under the dry extreme future climate. <How significant is that?>
Historically "the probability of rainfall exceeding 900 mm and runoff exceeding 130 mm in any one year is 20 percent. This probability reduces to 5 percent under the median future climate and to less than 3 percent in the dry"
Variability will increase substantially.
Days of low or no flow will increase.
Some numbers
Top section of table from the pdf. (Other rows, not copied, broke down results by geographical areas.) This table may be useful comparing for different scenarios and identifying just how bad it could get...rainfall down 14% and runoff down 42% by 2030.
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