Background

Orielton Lagoon is part of the Ramsar-listed Pitt Water-Orielton Lagoon. This tidal salt water lagoon is Tasmania’s only urban Ramsar site, located between Sorell and Cambridge, east of Hobart. Orielton Lagoon is classified as a Nature Reserve and is managed by the Tasmanian Parks and Wildlife Service (PWS).  

Pitt Water-Orielton Lagoon supports diverse marine life, attracts migratory birds, and serves a nursery for commercially important species. It also features significant saltmarsh diversity, providing critical habitats and supporting water quality. Historically, the area was the territory of the Moomairremener band of the Oyster Bay Tribe and holds significant Aboriginal cultural value. Today, it is a hub for fishing, birdwatching, and oyster farming. 

The catchment feeding the lagoon, via Frogmore Creek, Orielton Rivulet, and Sorell Rivulet, is primarily used for grazing and production, extending to the foreshore. The surrounding land is in transition from production and rural residential use to urban residential and service centre use, with substantial growth expected to persist for the next two decades.  

The vegetation along the riverbanks of Frogmore Creek, Orielton Rivulet, and Sorell Rivulet acts as a buffer between adjacent landscapes, the waterway and the wetland ecosystem. However, these riparian areas have been significantly impacted by land clearing, livestock grazing, trampling, and the spread of invasive species such as willows. Increasing urbanisation is also expected to further exacerbate these impacts.  

Through this project we are working with Landcare Tasmania, Sorell Council, private landholders and PWS to restore and remediate these riparian zones via a range of targeted actions including weed control, debris removal, revegetation, fencing and eco-hydrological restoration.

Weed control

We are working with Landcare Tasmania to oversee a targeted willow removal program along both stream banks of a 1 km section of the Sorell Rivulet. These efforts include the development of a willow removal plan, which will include input from a fluvial geomorphologist to assess erosion risks and recommend control measures. Willows are an invasive species that have colonised numerous riverbanks across Tasmania. They crowd out native species, decrease biodiversity in river systems and overall river health, and in the long term can contribute to the erosion of riverbanks and contribute to localised flooding.

Landcare Tasmania will engage qualified contractors to carry out removal using cut and paste and drill and fill methods, leaving willow stumps in place to stabilize riverbanks while native vegetation establishes. This is being followed up by revegetation to maintain stream bank integrity following willow removal.  

With support from Sorell Council and the Tasmanian Parks and Wildlife Service, we are also carrying out riparian revegetation works around Frogmore Creek, Orielton Rivulet and Orielton Lagoon. To support the success of revegetation efforts, other weeds will be managed as part of site preparation.

Removing debris

We are working with key partners to remove debris, including waste fencing and other litter, from 5.5 ha of riparian zones feeding into Pitt Water-Orielton Lagoon. The debris that has accumulated along these waterways all contribute to pollution entering the wetland, and impact on habitat quality and wildlife. We are working with Sorell Council to remove debris along Frogmore Creek, Orielton Rivulet and Orielton Lagoon, while project partner Landcare Tasmania will support Sorell Landcare volunteers to remove debris from a 1 km stretch of the Sorell Rivulet.

Revegetation and fencing

Working with project partners Landcare Tasmania and the Sorell Council, we are revegetating up to 11 ha of riparian habitat along Frogmore Creek, Orielton Rivulet, and Sorell Rivulet. This will help reduce sedimentation, create a buffer against erosion and nutrient runoff, and enhance the wetland’s microclimate. 

As part of these efforts, Landcare Tasmania is supporting Sorell Landcare volunteers to collect seeds from local ecological communities to propagate up to 8,000 plants for revegetation efforts, which will focus on maximizing buffer width and planting a diverse mix of native species to establish dense, structurally complex vegetation. This will include an overstorey, midstorey, understorey, and groundcover to support key species. By connecting riparian buffers to well-vegetated waterways and remnant bushland, the project will enhance habitat quality and biodiversity. 

Along Sorell Rivulet, Sorell Landcare volunteers are working to reconnect threatened vegetation communities, including Eucalyptus globulus dry forest and Eucalyptus tenuiramis forest, supporting the flyways of the endangered Swift Parrot. 

To safeguard these restoration areas and ensure the success of our revegetation efforts, we are also working with private landholders and contractors to install up to 5.5 km of fencing to keep out livestock and vehicles.

Eco-hydrological restoration

With the support of local landholders and Sorell Council we are engaging contractors to remove infill from selected areas of private land adjacent to Orielton Lagoon. This will restore natural tidal flows across 21 ha of wetland, improving connectivity and allowing the threatened temperate saltmarsh to gradually adapt to sea level rise. In addition to the works completed as part of our Blue Carbon project at Pitt Water-Orielton Lagoon, which saw the restoration of tidal flows across 65 ha of stranded saltmarsh habitat, these efforts are contributing to the broader health of this 3,334 ha wetland system.