Before the millennium drought, platypus foraging around the banks of the Coliban River downstream of Malmsbury Reservoir was a common sight.
However, climate change and challenging flow patterns have had a severe impact on their numbers, according to North Central Catchment Management Authority.
As a regulated river, the Coliban relies solely on water for the environment for flows, outside of large rain and flood events.
The bulk entitlement means very little water flows downstream of the last storage when the reservoir is not spilling and with no irrigation entitlements off the lower Coliban River, it is only a handful of stock and domestic customers who are licensed to take water.
‘‘Small amounts of water can be released from Malmsbury Reservoir every day, but that is not enough to keep it healthy if rainfall is low,’’ North Central CMA environmental flows project manager Darren White said.
‘‘For those platypus, that means large pools don’t connect and it is harder for them to find food without the danger of being attacked by a predator,’’ he said.
‘‘And a lack of water also means that from time to time, as has happened now, the Coliban River doesn’t flow all the way to the Eppalock Reservoir.’’
About 50Ml/day of water for the environment will head down the Coliban River from Malmsbury Reservoir in the coming weeks, for about three days.
‘‘That water will help the river reconnect to Eppalock Reservoir and will provide safety for platypuses as they travel to find food,’’ Mr White said.
‘‘It will also freshen up the water quality for the small-bodied fish in the river, as well as the vegetation they rely on to breed and feed.
‘‘We all know how important fish health is at the moment, especially as another hot, dry summer takes effect.
‘‘Water for the environment keeps waterways and the life within and around them healthy.
‘‘This also has ongoing benefits for recreation, such as fishing, as well as the homes and farms that rely on rivers for clean water.’’