Environmental watering of floodplains and weir pool manipulation underway

For the first time, three floodplain regulators at Chowilla, Pike and Katarapko will operate concurrently, along with weir pool raising at Locks 6, 5, 4 and 2 commencing in late July or early August with operations continuing through to November or December, subject to flow conditions in the River.

Program Leader, River and Floodplains Jan Whittle said the operations, to inundate areas of floodplain in need of a drink after a long dry period, are designed to achieve a range of benefits for floodplain and wetland vegetation and wildlife.

“This will be the second time the infrastructure at the Pike and Katarapko floodplains, built under the South Australian Floodplain Integrated Infrastructure Program, will be operated and tested, while the operation of the Chowilla environmental regulator will be undertaken for the fifth time,” Jan said.

“The watering at these key sites supports regeneration of the floodplain vegetation which provides valuable habitat for a range of wildlife.

“The floodplain watering and weir raising will connect wetlands and support the movement of carbon and essential nutrients to the river providing resources for food webs.”

Operations at Chowilla, Pike and Lock 5, Katarapko and Lock 4, and at Lock 2 will be supported by water for the environment provided by the Commonwealth Environmental Water Holder and The Living Murray, or natural flows due to upstream rainfall.

“At Pike, we want to raise water levels in the floodplain creeks by up to around 85 centimetres which is slightly higher than the 2020 watering. Lock 5 will also be raised in conjunction with the primary Pike regulator by 50 centimetres above normal pool level,” Jan said.

“If River Murray flows into South Australia increase and the event is running smoothly then we may raise levels by a further 20-40 centimetres, but the exact height will depend on the flow conditions.”

Jan said the planned watering at the Katarapko will raise water levels in the floodplain creeks by up to 1.5 metres but if flow conditions continue to improve this could be further increased to around 3.2 metres. Lock 4 Weir pool levels will be raised by an additional 30 centimetres above normal pool level.

Plans to operate the infrastructure on the Chowilla floodplain will also depend on River Murray flow conditions and approvals. A low to mid-level floodplain watering which would raise water levels in the floodplain creeks by between 2.6 and 3.3 metres above normal levels is planned along with raising of the Lock 6 weir pool by up to 42 centimetres above normal pool level.

“Depending on the scale of the watering achieved, there may be short-term vehicle access restrictions at Katarapko and within the Chowilla Game Reserve during the operations so we ask the community to adhere to the safety and hazard signage that will be in place,” Jan said.

“We’ll be monitoring how plants and animals respond to the watering and also tracking water quality during the events with stations set up throughout the creeks and River system to capture real time water information.”

Real time water information is accessible to the public via the Water Data SA web‐portal at https://water.data.sa.gov.au/

Final approval for the events is currently being sought with the operations expected to commence in late July or early August 2021 subject to flow conditions.

If you would like to receive updates relating to the events please email Engagement Officer Ellee Eleftheriadis ellee.eleftheriadis2@sa.gov.au with your contact details.

The Living Murray, is a joint initiative funded by the New South Wales, Victorian, South Australian, Australian Capital Territory and Commonwealth Governments, coordinated by the Murray–Darling Basin Authority.

The South Australian Floodplain Integrated Infrastructure Program was a $155 million program funded by the Australian Government through the Murray Darling Basin Authority.