Seven creek structures have been installed along Mulloon Creek as part of a catchment scale project to help rehydrate and regenerate the Mulloon watershed in southern NSW.
They are the first of nearly 100 structures to be installed along Mulloon Creek and its tributaries as part of the Mulloon Community Landscape Rehydration Project being managed by The Mulloon Institute in partnership with 23 local landholders.
The project aims to rebuild the Mulloon catchment's natural landscape function and boost its resilience against climatic extremes. A major focus is on creek repair and erosion control using small interventions to slow and filter water flow, preventing further erosion and beginning to rebuild the soil. This will lead to more reliable stream flows, improved ecosystem functioning and enhanced agricultural productivity.
The first of the creek works took place at Gerry Carroll’s Mulloon Farm property during March and April 2018. Seven simple v-notch log sill structures were installed with rock armour around the flanks and spill zone and lots of vegetation which will eventually cover the structures. The structures (sometimes called leaky weirs) are designed to slow the water down (not stop it) so it can recharge the floodplain aquifer, filter the creek water, and moderate flows during extremes of flood and drought.
The structures have already had a taste of rain with 80mm in late February seeing the creek flow over the first structure built, which was rather exciting. Conditions have turned hot and dry again but as of last week the creek continued to flow, albeit at a trickle, in and out of Mulloon Farm North.
Extensive revegetation works have been undertaken by members of the Manpower Green Army who have recently finished planting several thousand native water plants, sedges, shrubs and trees to armour within and around the structures along 2.5 km of the creek.
Hydrological, ecological and agricultural benchmarks were established well before any creek works began. Long-term monitoring against these benchmarks will determine how the structures influence the functioning of the system.
The next phase of creek works will begin in spring 2018.
Thanks to the NSW Environmental Trust for providing funding towards Stage 1 of the MCLRP. Thanks also to JG Earthworx for the excavator work, Schmidt Quarries for the rocks, and the Forestry Corporation of NSW for salvage logs. A big shout out also goes to the Green Army teams for their amazing contributions towards this project! And an even bigger shout out goes to Peter Andrews OAM who has continued to provide his priceless knowledge and insights to this project!
* NOTE: Before any rehydration works began in Mulloon Creek during this project, approval was gained from the NSW Government’s Office of Water.