September 2019 Summary
Rainfall was lower than average across 83 per cent of the area, spread throughout the drainage division. Large areas (33 per cent) had very much below average rainfall and lowest on record rainfall occurred in small areas of Gwydir, Namoi, Paroo, Border and Darling River regions. Mean rainfall was 11 mm – 67 per cent lower than the long-term mean of 33 mm and the ninth lowest for September in the past 120 years.
Due to the continuing dry catchment conditions, streamflows were very much below average including lowest on record since 1980 for 49 per cent of the sites, predominantly located in the north of the Basin.
Streamflows were fresh for 73 per cent of the sites and brackish for 11 per cent with median streamflow salinity (electrical conductivity) varying from 38 to 26024 μS/cm. The Darling River at Downstream Weir 19A had the highest salinity of all sites.
By the end of September, the volume of water stored across the Basin was 36 per cent of the total accessible capacity, a decrease of 16 per cent from the previous year. During September, accessible storage volumes increased in six systems, decreased in four and remained stable in eight. The storages in the Northern Basin had low total accessible volume, with most being less than 20 per cent and many less than 10 per cent.
|Rainfall decile group||Percentage of area|
|Highest on record since 1900||0%|
|Very much above average||0%|
|Very much below average||32%|
|Lowest on record since 1900||1%|
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