26 August 2024 | The health of the Sorell Rivulet was the centre of attention at a recent workshop run by Landcare Tasmania.

John Gooderham explaining the National Waterbug Blitz and how aquatic invertebrates are indicators of water quality. Photo credit: Luke Cooper. 

The 26 participants at the Sorell Rivulet Restoration and Willow Removal workshop heard from experts on the important ecosystem services local waterways provide, the impact that willow trees have on stream ecology, and the importance of riparian vegetation for water quality and biodiversity.

Kicking off the conversation, Landcare Tasmania project manager Anna Minchin talked about how the health of the Sorell Rivulet is vital for cultural, recreational, and water quality values in the Sorell sub-catchment and the Pitt Water-Orielton Lagoon Ramsar Site.

"Waterways in urban and rural areas are critically important for drinking water and growing food, and it is important that we care for the rivers and riverbanks to prevent flood, maintain natural flow and penetration into groundwater," she said.

The above map shows the Sorell Rivulet running from the north of the Sorell townsite and emptying into Pitt Water. Source LISTMap.

Anna noted that most of the Sorell Rivulet catchment area was private agricultural land.

"Private landowners are key to this project," she said, "and it's important to get the balance right between productivity and biodiversity." 

She explained that willow trees were abundant along the rivulet and while they do help stabilise stream banks, they are a weed of national significance and have detrimental impacts on the biodiversity and biological function of the ecosystem of the rivulet.

"Meanwhile the riparian vegetation on the Sorell Rivulet is in poor condition, being weed infested and largely non-existent. We need native vegetation along the rivulet as this helps to prevent erosion, provides habitat, improves water quality, cools water and reduces evaporation, which is particularly important in a changing climate." 

Simon Roberts delivering a talk on citizen science and water monitoring. Photo credit: Luke Cooper.

Next up, Simon Roberts talked about his passion for monitoring waterway and how community citizen science water monitoring groups, such as the Huon Waterwatch group which he heads up, are a powerful way to monitor river health and involve the local community. 

Samantha Milburn from the brand new Sorell Landcare group spoke about their goals and needing more members, and it was wonderful to see many hands go up showing interest in joining the group. 

Sorell Councillor Melinda Reed and Sorell Mayor Janet Gatehouse spoke about the Sorell Council Natural Resources Management (NRM) strategy and the council's support for the restoration of the Sorell Rivulet.

Greg Jordan, a contractor who has been removing willows from waterways for 40 years, shares some of his knowledge with the workshop participants. Photo credit: Luke Cooper. 

Following on from the talks, everyone headed out for a walk to view the Sorell Rivulet firsthand. Willow control expert Greg Jordan explained how it's best practice to leave willow roots in place as they can hold stream banks for 20+ years, so cutting off at the base of the tree is best for bank stabilisation. He also emphasised the importance of planting native vegetation immediately after willow removal works.

Waterbug expert John Gooderham spoke on using aquatic invertebrates to measure water quality. According to John, waterbug sampling on the day revealed a low diversity of species, indicating that the Sorell Rivulet is in poor condition. He said willow leaves are a big problem for waterways in autumn/winter. The leaves drop into the water and are broken down very easily by the microorganisms that eat them. This process consumes oxygen, and because it occurs so quickly, the oxygen can be completely depleted from the water, killing everything living in the waterway.

Feedback from participants was overwhelmingly positive:

• “I thought it was important to have the opportunity to meet new people of like mind with whom to start some initiatives.”
• “I learnt that environmental projects need planning, good background knowledge and long-term engagement.”
• “I was encouraged to learn that fortunately there are things that can be done on a small scale.”
• “I wanted to attend as I live close by and want to get involved at a local level.”

Anna explained there is little publicly available information on the water health of the Sorell Rivulet and this workshop aims to change that.

"This workshop was designed to forge relationships and partnerships to establish a long-term focus on the restoration of Sorell Rivulet."

The next steps include consulting with landowners along the rivulet and co-designing a community project with Sorell Landcare, Landcare Tasmania and Sorell Council.

Landcare Tasmania is also seeking partners and businesses that may wish to sponsor this project.

Reach out to us to find out more.

This workshop was co-funded by the Sorell Council and the Tasmanian State Government.

Thank you to the Honourable Kerry Vincent MLC for Prosser, Sorell Mayor Janet Gatehouse, and Sorell Councillors Melinda Reed, Beth Nichols and Marisol Miró Quesada Le Roux for attending.