Windermere Bay Saltmarsh Restoration

What’s special about Windermere Bay?

Long before we were here, this special place was cared for by the Muwinina people, whose families enjoyed living here for thousands of generations. The shape of the bay and the resources it provides made it a natural gathering place where families ate together and shared stories and ceremony.

Like much of the timtumili minanya/Derwent Estuary, these cultural landscapes are still recognised and honoured by the Palawa Community today for their cultural and natural values.

Located within Windermere Bay is an estuarine saltmarsh. These are extremely important ecosystems, supporting various plants, birds, insects and animals.

What is a saltmarsh?

A saltmarsh is an estuarine or coastal marsh, located in the intertidal zone, where saltwater meets the land between high and low tides. Freshwater also flows through these areas from rainfall, groundwater and creeks.

This inundation of water is essential for the ecosystem to operate and benefits wildlife, fish and people. Managing these areas is necessary to keep our waterways healthy, communities safe, and places for us all to enjoy.

The saltmarsh in Windermere Bay contains many unique saltmarsh plants, which are specifically adapted to the unique conditions and need regular water inundation to nurture them. This provides essential habitats, protection and food for many animals, including fish, birds, worms, snails, crabs, mammals, and insects.  

These environments also provide incredibly important system services, including storing carbon from the atmosphere, improving water quality, protecting the coastal area and reducing flood risk. Healthy saltmarshes are nature’s water filters in coastal environments. 

Many of these systems exist throughout the Derwent Estuary, including several in Old Beach, Ralphs Bay and Piyura Kitina (Risdon Cove).

Saltmarsh restoration

It's important to protect and preserve the Windermere Bay saltmarsh so we can all share and respect its cultural and natural values.

The Derwent Estuary Program, in collaboration with the Glenorchy City Council, is managing a saltmarsh restoration project in Windermere Bay.

We aim to restore and increase the area of saltmarsh alongside Glenorchy City Council's project to upgrade the boardwalk.

The old boardwalk across the saltmarsh will be replaced and extended over Faulkners Rivulet to provide a great connection between both sides of the foreshore track in the bay.

Why are we restoring the saltmarsh?

You might think that the saltmarsh here looks healthy, and it is!

However, the total area of saltmarsh in the bay was much larger than it currently is. In the 1960s and 1970s, infill was placed on some areas of the saltmarsh, reducing the total area by approximately 0.7 hectares. We aim to restore the saltmarsh area adjacent to Faulkners Rivulet by removing this infill and allowing the passive restoration of saltmarsh communities.

In the past six months, we have gathered information about the site's water, soil, plants, and animals to help create our restoration plan.

What will the restoration work look like?

To remove the relatively large volume of soil from the historic marsh area, we will need the help of large excavation machinery.

The soil will be excavated to its previous level so that tidal flows from the estuary and flooding from Faulkners Rivulet can easily pass over the soil.

Initially, it may look bare and exposed, but it won't stay that way. Within six months of removing the soil, we will start to see re-growth of saltmarsh plants, which will return to a healthy cover within a few years.

Once we've excavated the soil from Windermere Bay, we will install temporary fencing to limit trampling, and plant native species around the restoration area to create a natural buffer.

We will also replace the large group of woody weeds on the bank adjacent to the road with native plants.

Here are photos showcasing the healthy regrowth of a similar restoration project on Tasmania's east coast 18 months after excavation.

Passive restoration

Passive restoration means letting the saltmarsh restore itself once the area has been scraped and fenced. This means we won’t be planting saltmarsh species. They will naturally return either through seed banks still in the soil or seeds from the neighbouring saltmarsh.

Previous projects tell us this natural restoration could take between four to 15 years for a full recovery. During this time, we will monitor the recovery and carry out weeding to prevent invasive plants from taking over. Other living species, such as birds, fish, crustaceans, birds, and macro-invertebrates, will recover in different timeframes.

Birds return quickly to restored saltmarsh areas, using these areas almost as soon as the water flows resume. Fish and crustaceans are known to return to similar levels within a year of restoring saltmarsh landscapes.

Macroinvertebrates can take longer to recover. Macroinvertebrates are small animals without a backbone.  They include animals such as mayflies, snails, worms and mussels and live in rivers, estuaries and wetlands for part of their life. There are thousands of aquatic macroinvertebrate species, and they are a key food source for platypus, fish, and frogs.

An important indicator of river health, macroinvertebrates may take longer to recover in numbers and species, taking five to 15 years to recover fully.