Tidbinbilla Station landscape rehydration works

Aerial view of looking upstream after Stage 1 works completed.

Mulloon’s Principal Landscape Planner Peter Hazell, Landscape Planner Jack Smart and Field Officer Max Brunswick recently completed construction of in-stream Landscape Rehydration works on the Tidbinbilla River in the ACT. The works, which were carried out on the property ‘Tidbinbilla Station’, involved the construction of four log-sill bed control structures and comprised Stage 1 of a planned three-stage construction program to repair a deeply incised and eroded 1,500 m section of the Tidbinbilla River. Construction occurred over two weeks in June 2023. 

Mulloon Consulting worked closely with the landholders, Southern ACT Catchment Group and the ACT Government in the preparation of designs and approvals to undertake the works.  

Above: Structure TS3 right bank looking upstream before (left) and after (right).

The recently completed works aim to address historic stream erosion and incision by raising the bed level of the stream by around 1m and in doing so, slow the flow of water and encourage the spreading of flows across the landscape. This is expected to achieve a range of positive outcomes including: 

  • Decreased risk of large sediment loads entering the Paddy’s River Catchment in future large rain events 

  • The beginning of the establishment of diverse native vegetation along the channel including: 

  •  dense beds of macrophytes within the channels, and 

  •  native groundcover and shrubs and trees along the extensive gravel bars; 

  • Extending baseflow duration via alluvial aquifer recharge and discharge 

  • Buffering of flood peaks  

  • Capture and storage of fine sediment 

  • Increase carbon capture and storage 

  • Enhancing aquatic and terrestrial habitat and connectivity  

  • Improving rural landholder engagement in regenerative techniques.

Above: Structure TS5 left bank looking upstream before (left) and after (right). Note: construction of Stage 2 structures downstream of this site will provide additional depth of water to the downstream side of this structure, further dissipating the energy of flows at this site.

Following the successful completion of the Stage 1 works, planning is underway to commence construction of Stage 2, which will include a further seven log-sill bed control structures. Construction of this next phase of works is scheduled to be undertaken in spring 2023. It is hoped that the restoration of this degraded section of the Tidbinbilla River will serve as a successful demonstration of Landscape Rehydration and floodplain restoration within the Paddy’s River catchment and the ACT more broadly. 

Funding for this project was provided through a combination of ACT Environmental Grant funds through the Southern ACT Catchment Group and landholder contribution. 

Looking upstream through the drone, before (left) and after (right).

Cass Moore