There is set to be an environmental water release from Burrinjuck Dam in mid July 2017. The purpose of the release it to improve the health of the river, creeks and wetlands in the mid-Murrumbidgee River.
It is expected to reach 3.7m (or 20,000 ML/d) at Wagga Wagga. This is lightly below the summer irrigation height and well below the flood high of 7.3m. This release will only cause minimal inconvenience to the river users but will put the good fishing conditions on hold during its duration.
While this will make an immediate impact on anglers and stop them from fishing the river for 3-4weeks it will be beneficial for our river health in the future. Read more below to find out why this release is being done and how it is beneficial to the river system.
Why is it being done?
When connected to the river these wetlands provide critical breeding and foraging habitat for native fish, waterbirds, frogs and other fauna. They support native wetland plants which help to improve water quality and help to produce zooplankton, insects and crustaceans which are important food for juvenile fish. This water delivery will also help to move nutrients and carbon back into the river during winter when the water is cooler, supporting the river food web.
Whose water is it?
Water allocation is being made available by the Commonwealth Environmental Water Holder and from NSW environmental water allowances.
How much water will be released and for how long?
The planned total volume is up to 200 gigalitres (GL). The total duration of dam releases for the event is expected to be 17 days.
The actual volume released will depend on allocation levels for 2017/18 water year and operational conditions, including season and local inflow status. Depending on these conditions, the duration of the peak flow is planned to be 5-6 days in the upstream river reaches, increasing to 12 days further downstream.
What river level is the flow expected to reach?
The environmental water releases are targeted to reach a river level of 3.7m (or 20,000 ML/d) at Wagga Wagga. This is far below the minor flood level of 7.3m and slightly below peak irrigation season water levels of summer 2013.
A flow height of 3.7m is known to be of minimal inconvenience to river stakeholders. If heavy rainfall is unexpectedly predicted after the planned release of environmental water, river operation will be managed accordingly. The event may be postponed or immediately ceased, so as to minimise the chances of exceeding the target river levels.
The flow recession will be gradual (modelled natural rate of recession) with the aim of minimising river bank erosion.
You can read the full PDF document on the water delivery event below:
Information supplied by Office of Environment and Heritage