Review of May 2018 Operations
310 ML of measurable inflow was received into reservoirs during May. Between July and May 67,570 ML of inflow has been recorded into headworks storages, which is 37% of the historic average for the same period (182,500 ML).
During May, the volume in headworks reservoirs decreased from 259,930 ML (46%) to 256,630 ML (45.8%).
Rainfall was slightly below average at all reservoirs during May. The highest rainfall for the month was 94mm, recorded at Bellfield Reservoir followed by 84mm received at Lake Wartook.
Environmental water releases continued during May, with 920 ML supplied from Lake Wartook to the MacKenzie River, and 340 ML released from Lake Lonsdale to provide baseflows to the lower Mt William Creek. Rocklands Reservoir released 1,600 ML of environmental water to the Glenelg River. Taylors Lake delivered 960 ML to the Wimmera River once the flow resumed in the second week of May after maintenance works on the outlet channel.
Wimmera-Mallee Pipeline supplied Recreation Lakes received 60 ML. 21 ML was supplied to Wimmera-Mallee Pipeline connected wetlands within the Mallee, North Central and Wimmera Catchment area during the month.
Consumptive entitlement holders collectively used 1,000 ML during May to supply urban and rural demands.
The rainfall for the month was slightly below average, net evaporation from reservoirs was approximately 2,050 ML for the month; with rainfall exceeding evaporation, (Net evaporation considers rainfall on the reservoir as an evaporation offset).
Planned June 2018 Operations
The Bureau of Meteorology (BoM) in their most recent climate outlook have predicted a 25% to 35% chance of above average rainfall this June. BoM reports that the El Niño Southern Oscillation (ENSO) remains neutral which means neither El Niño nor La Niña. The current neutral ENSO will continue for at least the winter months.
A neutral ENSO phase has little effect on Australian climate. The Storage Manager will continue to monitor BoM climate outlooks and consider this information in its planning activities.
Storage Manager will publish new annual operating plan for 2018-19 early next Month.
There are no transfers between reservoirs planned for this month, however the Storage Manager will continue to monitor conditions. Further information in relation to water transfers are described in the Storage Manager’s Annual Operating Plan.
The release of environmental water and the routine delivery of water to consumptive entitlement holders is expected to be the Storage Manager’s operational focus during June. Due to dry catchment conditions, substantial rainfall will be required to wet catchments and begin generating inflow to reservoirs. As the catchment becomes saturated and inflows begin to occur, the Storage Manager’s focus will transition to water harvesting operations.
Reservoirs are expected to remain at suitable levels through June for a range of recreational activities, including boating at reservoirs where this is permitted. Please refer to the Reservoir information page for further information on water levels and recreation activities permitted at each reservoir.
While Blue-Green Algae (BGA) blooms are generally less common during the cooler months, there is still ability for these to occur. Recent Blue-Green Algae warnings for reservoirs can be found on the Storage Manager News Feed and all current warnings are available from the GWMWater Algae Warnings webpage.