Menindee flood relief hampered
Tuesday, 29th March, 2011
Recent rainfall has set back relief from flooding around Menindee, as State Water continues to monitor weather conditions so it can respond to any new flood threat.
The Office of Water, together with State Water, released its seventh information paper on inflows, levels, operations and management of the Menindee Lakes - which are at full capacity - late last week.
The report said that releases from the Menindee Lakes to the Lower Darling River and Great Darling Anabranch were being managed as floods from northern NSW and Queensland pass through the Darling River system.
Recent rain in the area from Wilcannia to Menindee has also produced large local runoff, leading to greater than expected inflows to Menindee Lakes, according to the report.
Flows through Weir 32 are down from a peak of 37,000 Megalitres a day (ML/d) and have been held for the past week at 28,000 ML/d to pass on the additional inflows.
With more rain expected next month, outflows at Weir 32 will be increased to around 30,000 ML/d and the release from Cawndilla Outlet to the Anabranch will also be increased from 600 ML/d to 1,500 ML/d to accommodate the additional inflows.
The rain has set back relief from flooding around Menindee by at least two weeks as it will now be difficult to get flows to Weir 32 down to around 18,000 ML/d before mid to late April, according to the report.
Full supply level of Menindee Lakes is 1,731,000 ML. The current management strategy is to fill the lakes to a maximum storage of about 2,000,000 ML (surcharged to 116 per cent capacity) in mid to late April, then to reduce flows and water levels in the Lower Darling at a rate which will minimise the potential for riverbank damage.
Lake Wetherell is now at 93 per cent full, Lake Pamamaroo is at 120 per cent capacity, Lake Menindee at 104 per cent and Lake Cawndilla at 103 per cent.
Meanwhile, nearly all the lakes along the Anabranch have received water, most for the first time in 10 years.
The NSW Office of Water will also provide instruments for the early detection of potential blackwater.
With the improved flow in the Lower Darling is attracting more visitors, boat owners are asked to minimise the wash from vessels to avoid damaging riverbanks, especially as water levels begin to fall.