Adelaide Hills waterfalls roar to life after record winter rainfall inflows

Waterfalls in the Adelaide Hills have roared to life after reservoirs across the region received their highest inflows over 24 hours in nearly a decade.

Lightning, heavy rain and small hail swept across Morialta Conservation Park east of the city at about 2:30pm yesterday, turning its usually gentle waterway into a raging torrent reminiscent of tropical Queensland.

Across the Mount Lofty Ranges, about 18 billion litres flowed into the state's metro reservoir system in the 24 hours to 8am today, according to SA Water, lifting the combined storage level by 9 per cent to 73 per cent of capacity.

He said Mount Bold, the largest reservoir with a capacity of 46.4 gigalitres, received more than 5 billion litres of water, lifting its storage level by 13 per cent to 82 per cent of capacity, with Kangaroo Creek increasing by 19 per cent.

"Relative to the size of their catchments, Little Para and South Para reservoirs were some of the main beneficiaries of this rainfall, with their storage levels increasing by 7 per cent and 10 per cent respectively," Dr Kingsborough said.

More than 71 billion litres of water has flowed into the metro reservoirs since the beginning of winter, leaving them well over the storage holding of 55 per cent at this time last year.

"A wet start to winter laid the groundwork by helping increase soil moisture across our catchments, and we're now seeing the benefit of this on our reservoirs, through the cumulative impact of rainfall events like yesterday," Dr Kingsborough said.

The last time SA Water needed to release water at Mt Bold, which is typically triggered when storages reach above 95 per cent of capacity, was in November 2022.

"We will continue working in partnership with the Bureau of Meteorology [BOM] to monitor forecast rain and water levels in our reservoirs, to guide any potential releases of water from Mt Bold," Dr Kingsborough said.

"Our reservoirs are in a healthy position heading into spring, and we will keep a close eye on our storage levels to ensure a secure water supply for our customers in advance of what the BOM is forecasting to be a dry late winter and spring."

Bushwalkers urged to use caution

The Kaurna name for Morialta Conservation Park's Fourth Creek is Moriatta, which means "ever flowing", although that is no longer the case due to upstream dams and agriculture.

Its water flows through Morialta and into the River Torrens system, but occurs below reservoir catchments so does not impact upon storage levels.

Bushwalkers visiting the site are urged to stick to trails and stay behind guardrails as it has been the site of several rescues and fatal accidents.

"Visitors are responsible for their own safety and should follow advice from park rangers, comply with all warnings and other park signage, stay on marked trails, and remain behind safety barriers that are installed to protect the public," a Department for Environment and Water spokesperson said last month.