Palerang leaky weirs - before + after
This series of before and after photos depicts three of 15 leaky weir sites at ‘Palerang’ – one of the properties taking part in the Mulloon Rehydration Initiative (MRI). This component of the MRI was undertaken with funding support from the NSW Government through its Environmental Trust. The broader Mulloon Rehydration Initiative is jointly funded through the Mulloon Institute and the Australian Government’s National Landcare Program.
The structures were built in November 2019, while much of the east coast was in the grip of an unprecedented drought that culminated in the Black Summer bushfires. Note, that in one before image the air around the structures is thick with smoke. Two months after the structures were built, the rains came. Ash and silt were washed from the upper catchment. Ponds were instantly created behind each of the fifteen structures on ‘Palerang’. Since the first rains in February 2020, Mulloon Creek has experienced record breaking rainfall, many major flow pulses and two once-in-a-generation floods (see hydrograph below).
The images paint a picture of a system that is becoming more resilient to both droughts and floods. Water is retained in the system for longer into the dry periods. During wet periods the flows are low energy, spreading and deposit sediment, rather than high energy and erosive. Dry, bare sand banks are now revegetating with native plants. The water is clear and water plants are emerging. The scene is repeated throughout the entire length of Mulloon that has now been treated with landscape rehydration infrastructure.
