Catchment Action
Mulloon Rehydration Initiative
The Mulloon Rehydration Initiative (MRI) is a fully benchmarked, catchment scale, landscape regeneration project involving 23 landholders and covering an area of 23,000 hectares. A major tributary of the Shoalhaven catchment, Mulloon comprises about 1.5% of Sydney’s drinking water catchment.
A critical component in improving catchment health is addressing gully and stream erosion. Prior to commencement of the MRI in 2014, Mulloon Creek and its tributaries were deeply incised, and in many cases still actively eroding, almost throughout the entirety of the system.
While this is still the case for much of the system, around 15km of Mulloon Creek, across seven properties, has already been treated, with over 50 bed-control structures installed, along with riparian fencing and revegetation.
Aims and objectives
Led by The Mulloon Institute, and working with the landholders of Mulloon, the MRI aims to address chronic issues affecting landscape function, including soil erosion, over-grazing, and loss of biodiversity. Boosting landscape function will also rebuild the resilience of the catchment to the extremes of drought, flood, and wildfire.
Treatments within Mulloon Creek have comprised stream bed-control structures aimed at addressing the energy imbalance within the system that is causing erosion of the streambed and streambanks.
Installed as a series throughout a given reach, these structures begin the process of raising the stream to its pre-European levels. The structures recreate a pond riffle sequence, slowing and spreading the flow, allowing deposition of sediments, the amelioration of nutrients, and the re-emergence of complex aquatic and riparian habitat.