Review of March 2018 Operations
No measurable inflow was observed to reservoirs for a fourth consecutive month during March. Between July and March 67,250 ML of inflow has been recorded into headworks storages, which is 39% of the historic average for the same period (174,200 ML).
During March, the volume in headworks reservoirs decreased from 283,700 ML (50.6%) to 268,750 ML (48%).
The Storage Manager completed a transfer of approximately 2,000 ML from Lake Bellfield to Lake Fyans during the second week of March. The transfer was initiated to secure water supplies in Lake Fyans, manage risks of adverse water quality, and support recreational pursuits. The transfer was timed to take advantage of relatively mild temperatures and a rainfall event, to improve transfer efficiency.
Rainfall was below average at all reservoirs during March. The highest rainfall for the month was 24mm, recorded at Lake Wartook.
Environmental water releases continued during March, with 740 ML supplied from Lake Wartook to the MacKenzie River, and 190 ML released from Lake Lonsdale to provide baseflows to the lower Mt William Creek. Environmental water releases from Taylors Lake delivered 930 ML to the Wimmera River and Rocklands Reservoir released 1,500 ML of environmental water to the Glenelg River.
Wimmera-Mallee Pipeline supplied Recreation Lakes received 260 ML during the month.
Consumptive entitlement holders collectively used 1,280 ML during March to supply urban and rural demands.
Due to below average rainfall, net evaporation from reservoirs was approximately 5,500 ML for the month; with evaporation exceeding rainfall, (Net evaporation considers rainfall on the reservoir as an evaporation offset).
Planned April 2018 Operations
The Bureau of Meteorology (BoM) in their most recent climate outlook predict a 40% chance of above average rainfall this April. The Bureau of Meteorology (BoM) reports that the El Niño Southern Oscillation (ENSO) indicator has eased back to ‘neutral’- with neither El Niño nor La Niña conditions dominating. This means that the ENSO outlook has shifted from ‘La Niña’ to ‘Inactive’.
The recent weak La Niña conditions had relatively little effect in terms of increased rainfall, although they may have contributed to the warmer than average temperatures experienced over the last few months. The current neutral ENSO indicator suggests that conditions over the coming months will not be particularly wet or dry. The Indian Ocean Dipole (IOD) is currently neutral and is predicted to remain so throughout autumn. The Storage Manager will continue to monitor BoM climate outlooks and consider this information in its planning activities.
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 April.
Reservoirs are expected to remain at suitable levels through April 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.
Blue-Green Algae blooms can be more common during the warmer summer and autumn months. 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.