Water for the environment goes with the flow

The Goulburn Broken Catchment Management Authority plans to release water from the Goulburn weir from mid-September to improve habitat and food sources for native fish, platypus and water bugs in the Lower Goulburn River.

Goulburn Broken CMA environmental water and wetlands manager, Simon Casanelia, said the annual water release was referred to as the Goulburn River early spring fresh.

“A fresh is flow that increases the height of the river for a short period of time and scientific monitoring has shown this is one of the most important flow events for the ecology of the Goulburn River,” Mr Casanelia said.

“It occurs when flows would naturally be high and brings food and nutrients into the river to feed plants and animals ahead of summer.

“The flow boosts food resources and available habitat for native fish, platypus and water bugs by inundating connected anabranches and wetlands, increases bank soil moisture which helps stabilising plants to grow and moves sediments from the riverbed to maintain habitat for water bugs and native fish.”

Lake Eildon releases may be used to provide the spring fresh, but if the rainfall continues it’s likely the environment will look after itself and the fresh will be provided by natural flows.

If all goes to plan, the fresh is due to start on 15 September and peak late September at approximately 9,500ML/day (a river height of 5.6m at Shepparton) before slowly dropping back to approximately 1,000ML/day (a river height of 2.7m at Shepparton) in mid-October. This is well below the minor flood level (9.5m at Shepparton). Timing of the fresh may vary depending on natural flows in the river. Delivery of water for the environment will reduce or cease if there is any risk of flooding.

 Mr Casanelia said good rainfall over winter had led to natural flows in the tributaries above Goulburn weir and water for the environment was used to pass these flows though Goulburn weir, rather than being diverted off into irrigation areas.

“Even in wet years, river operators are only required to pass very low flows through Goulburn weir, around half of the minimum needed to provide critical habitat for fish, water bugs and plants, so when it’s wet we aim to use water for the environment to create higher flows, which still only mimic a small proportion of what would have occurred naturally in the river.”

Environmental flows are planned by the Goulburn Broken CMA in consultation with the Commonwealth Environmental Water Office and the Victorian Environmental Water Holder (VEWH) as well as Goulburn-Murray Water, who manage the releases of environmental flows from its storages.

This use of water for the environment is authorised by VEWH in line with its Seasonal Watering Plan 2022-23, which is available for download from www.vewh.vic.gov.au, with regular watering updates posted on the Goulburn Broken CMA website www.gbcma.vic.gov.au

Timing of the environmental flows take into consideration seasonal conditions, delivery orders by irrigators and other water users and feedback from the community via the Goulburn Broken CMA’s environmental water advisory groups.

Providing water for the environment is only one way of protecting and improving rivers and wetlands. The Victorian Government is investing $248 million over four years (2020-2024) to improve catchment and waterway health across regional Victoria. This investment is a key component of Water for Victoria – the government’s plan for management of our water resources now and into the future, and includes activities such as:

• the delivery of on-ground works (e.g. fencing, habitat, pest control and revegetation) to improve habitat, both along and in our waterways;
• provision of water for the environment to support native plants and animals; and
• better coordination and management of our catchments and Ramsar sites – which are some of the most unique and important wetlands sites in the world.

Find out more about river health, water for the environment and monitoring activities at www.gbcma.vic.gov.au 

To check flows in the Lower Goulburn, view the hydrograph on Goulburn Broken CMA’s website:  http://fchmccoys.hydronet.com/ (updated weekly).   

The Goulburn River at Shepparton North - A water release increases the height of the Goulburn River for a short time and improves habitat and food sources for native fish, platypus and water bugs.