Water is making its way into Lake Menindee for first time in half a decade, a development described as the last nail in the coffin of drought in NSW.
The return of water into Lake Menindee will occur during the second significant influx of water into Lake Wetherell and Lake Pamamaroo, from the Barwon-Darling River in the past 12 months.
Lakes Wetherell and Pamamaroo had been receiving low volume inflows since February, prior to a major rain event in northern NSW and southern Queensland in March that deposited large volumes of water into the upper catchment.
The resulting flow is expected to deliver up to 850 gigalitres (GL) into the lakes system by early June. The combined total storage capacity of the lakes when full is approximately 1700GL.
Modelling indicates that between 300-500GL will be released into Lake Menindee, of which approximately 100GL will be lost to seepage into the dry lakebed.
Opening the gates today in Menindee, Minister for Water, Property and Housing, Melinda Pavey said while much of the initial flow into Lake Menindee will be absorbed by the parched lakebed, the return of the water restores NSW Government long-term environmental watering objectives, put on hold by severe drought.
“Lake Menindee is a precious environmental and cultural asset. While the volume of water which will enter that lake will be comparatively small compared to Wetherell and Pamamaroo, the water will rejuvenate the foundations of its complex ecology,” Mrs Pavey said.
“By the end of this event, around early June, we will have the two upper lakes at capacity, water returning to Lake Menindee, and a welcome extension to the water security outlook for the farm families and communities of the Lower Darling.
“Being able to return water to this dry lake means seepage losses from the next inflows will be hugely reduced and the potential to add volume to the lakes enhanced with each subsequent flow event.”
Minister for Agriculture and Western NSW Adam Marshall said returning water to Lake Menindee will benefit the local environment through the release of nutrients from dry lake sediments.
“The increase in available food resources would benefit waterbirds as well as fish and turtles into the future,” Mr Marshall said.
“Past refilling of the lakes have seen these animals become highly productive and provide opportunities for species to complete lifecycles and replenish egg deposits in drying sediments.”
Mrs Pavey said after years of enduring the worst of the drought all major regional river valleys are recovering, with the regional supply dams sitting on average above 50 per cent of capacity, compared to 25.5 per cent this time last year.
“The return of water to Lake Menindee is not just a welcome step in hopefully re-filling the Menindee lakes, it represents a symbolic last nail in the coffin of the drought that held this region and much of the state in its cruel grip for so long,” Mrs Pavey said.
“The very fact that the water has been arriving here in recent months means that it is also replenishing the environment, the town water supply weirs, and the needs of agricultural producers and farm families all the way from the Queensland border, bringing sustained relief to a region of NSW that suffered the longest and most severely during the drought.
“Our priority now must be to store and utilise this water in such a way that its maximum benefit is realised to communities, the economy and the environment to which it is so critical,” Minister Pavey said.
WaterNSW estimates that the lakes’ total volume could exceed 640 GL in early May, meaning the lakes’ storage becomes the shared resource of the River Murray system.
As a result the Murray–Darling Basin Authority can access water in the lakes on behalf of the joint governments of South Australia, Victoria and New South Wales, and to support entitlements in the River Murray.
The last time the lakes’ volume exceeded 640 GL was October 2016. The volume fell below 480 GL and reverted to NSW Government control in December 2017.