River Murray flood fears grow as grass fire threat takes root

Fears of twin natural disaster threats are growing as the amount of water flowing into and falling onto SA continues to swell.

The state could face simultaneous fire and flood risks as interstate rain swells the River Murray, while new fuel loads grow in drier areas.

Daily Murray flows into SA have almost doubled in only six weeks, and heavy spring rains have prompted a Bureau of Meteorology fire warning.

At the beginning of September SA was coping with water inflow of 43GL (billion litres) daily, but on Thursday it was 77GL, and many areas of Victoria are flooding this week.

While the peak of flows from the eastern states is not expected until next month, in a sharp contrast SA has been put on fire alert by BOM.

The SES is responding to flooding across Victoria on October 13. Picture: SES

It predicts for the 2022/23 fire season: “Normal bushfire potential in eastern states, but an elevated risk of grass fire in southern Australia”.

“Above-average rainfall over winter has led to good grass and vegetation growth in many areas, which can increase the risk of grass fires.

“While long running large bushfires are less likely than during a drier season such as 2019–20, continuing wet conditions during spring may further increase grass growth.

“This could increase fire danger during any period of hot and dry weather over summer.”

The extent of the expected SA flood threat from the vast but mainly distant catchment of the Murray-Darling Basin is as yet unknown, but levels of rivers and dams are already rising.

The basin covers most of Victoria and NSW and a large portion of southern Queensland.

SA Water daily measures Murray flow at six locations, including at the border with Victoria.

The BOM is also expecting more heavy rainfall as this week ends with areas in the catchment — southern New South Wales, northern and central Victoria — likely to have 30 – 80mm of rainfall.

Large areas of the two states are on flood alert and outside Melbourne 100mm of rain was recorded in the 24 hours to Wednesday night.

Water levels will not peak until early next month, but SA inflows have already exceeded the expectations of the Department for Environment and Water.

Using the SA Water data for its predictions, the department expected the high point to be 75-80GL a day by late early November, but that has already been reached. Heavy rain has continued in the basin.

The water flow is already the highest the Murray has been since 2016 when daily flows reached 95GL.