Changing climate

BY ABBY WALTER

The Wimmera is no stranger to years of below-average rain.

After three consecutive La Niña events, Wimmera residents will likely experience a ‘significant change’ to weather patterns as the Australian Bureau of Meteorology reports signs of El Niño forming in late 2023.

La Niña patterns typically mean years, or seasons, of above-average rain; while El Niño indicates probable below-average rain across northern and eastern Australia.

While currently in a neutral state, the bureau has moved to El Niño watch, which means there is a 50 percent chance of El Niño this year. Wimmera Catchment Management Authority chief executive David Brennan said the region was moving out of the wetter weather patterns experienced in 2022.

“The next outlook is still uncertain as while we are confident we have moved away from a wet period, during the coming weeks we will get a clearer picture of what is to come,” he said.

“We have not had a lot of rain in the Wimmera since December and if we move into drier patterns, that will be a significant change to what we saw last year.”

The Wimmera recorded between 650 millimetres and 900 millimetres in 2022, with towns experiencing up to 300mm more than annual averages.

To mark the third La Niña in three years, Wimmera residents experienced flooding of properties and roads and all eyes were on a rising Wimmera River in October.

Since 1997, average inflow to Grampians catchments has been 85,000 megalitres.

In 2022, there was 300,000 megalitres of inflow to catchments.

GWMWater manager of water resources Kym Wilson said Grampians reservoirs in November 2022 held the greatest volume in storage since 1997 – a year that marked the beginning of the Millenium Drought. “Winter and spring 2022 saw above- average inflow to Grampians reservoirs,” he said.

“Winter and spring 2020 and 2021 both yielded well below-average inflow for Grampians reservoirs.

“An El Niño event increases the chance of below-average winter and spring rain.

“If it is a very dry season as a result of El Niño, below-average inflow to reservoirs is likely, and water storage levels may be lower heading into next summer.”

Mr Wilson said the nature of Grampians catchments was they had ‘boom’ and ‘bust’ years. “The stor- age capacity within the Grampians reservoirs mean that after a wet year, there is often enough water reserved in storage to meet supply for a number of years – even if they are drier years,” he said.

“However, even when water is plentiful, it’s still important to use water wisely. Consumption tends to be influenced by factors such as temperature and rainfall.

“Communities tend to use more water when it is hot and dry.”

Mr Brennan said drier weather patterns often put pressure on water resources and the environment.

Continued page 3