Erosion control and Fish Habitat Restoration, Bellinger River

Stabilisation of an eroding bank to reduce sediment influx and improve fish habitat

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The issue

A section of bank along the Bellinger River's lower reaches continually degraded due to mass slumping of the saturated riverbank, following flood events.

Steep, near vertical alluvial banks, lacking a stable bank toe, result in slumping and loss of mature upper bank vegetation, and an absence of any habitat for fish.

The solution

Landcare assisted the owner to obtain funding from the NSW Department of Primary Industries and Regional Development, to reshape and reinforce the bank to prevent ongoing slumping and enable re-establishment of riparian vegetation, through planting and natural recruitment. Timber pins, root balls and rocks stabilised the eroding bank toe, placed in a ‘rough’ and ‘irregular’ manner to provide flow energy dissipation, enhanced vegetation colonisation and habitat for aquatic species.

Reshaping the upper bank to a reduced batter enabled revegetation with endemic riparian species, improving canopy connectivity, bank stability and habitat availability.

The impact

Seventy-five meters of eroding bank was fenced from stock and stabilised, with sediment runoff reduced. Several hundred riparian plants have been established, and high quality fish habitat was created, which will benefit the fish and also the fishing public who frequent the area.

A fact sheet, field visit and subsequent planned visits and publicity will continue to educate the public about the benefit of erosion control and habitat creation, and showcase a practical example.

Learnings

It appears that the project works are well established and the project has succeeded. The next few major flood events will highlight any adjustments that may need to be made.

The work was significantly delayed by lengthy approvals processes, and flood events, leading to increased costs which had to be accommodated by the owner.

Working with natural systems will always be subject to extreme events, occasionally causing significant delays. In this case DPIRD was very flexible, allowing for several variations to the project to enable it to be delivered despite the above challenges.

Author: Jason John