River flows were very low, with few flood events, declining water storages and drying wetlands.
National river inflows were very low at 52 mm or 407,000 GL; 43% below the 2000–2018 average and 22% less than in 2018.
Extremely low river flows occurred in catchments in the Darling Basin, along the Southeast Coast and in the Timor Sea Basin.
The combination of negligible inflows, algal blooms and a sudden change to cooler weather caused mass fish kills in the Darling system.
River flows were well above average along the northern Queensland coast, and around Karratha in WA and Strahan in Tasmania.
Major floods occurred from Townsville through to the Gulf of Carpentaria due to persistent heavy rainfall in January and February. An estimated 600,000 cattle perished.
Further cyclone-related flooding occurred in March around Karratha and Port Hedland and in the Channel Country and surrounding regions.
Storage in the major irrigation reservoirs declined: combined storage in the five largest storages in the Murray-Darling Basin storage fell from 47% to 35% of capacity, and Ord Reservoir storage fell from 61% to 34% of capacity.
Urban water supplies declined for many cities, including Sydney (28% less than the previous year), Brisbane (-25%), Canberra (-26%). Several smaller towns in the Darling Basin ran out of regular water supplies entirely.
The extent of wetland flooding was low. Total inundation fell for a third year, to the smallest area since 2002, or 26% below the 2000–2018 average.
Wetland extent was the lowest since at least 2000 in many catchments, including much of WA, Northern Australia and the Murray-Darling Basin.
Conditions were normal in the Lake Eyre Basin and above average in northern Queensland and western Tasmania.
source: Australia’s Environment in 2019 Summary Report (link)