The Thomson River, a 210 km river in the south east of Victoria, Australia hosts a large variety of native fish species including IUCN Red List species. It flows from the Alpine region in Victoria to the Ramsar Listed Gippsland Lakes.
In 1911 a river diversion tunnel was constructed in the rugged mountainous region of the river, to allow easy access to alluvial gold. The tunnel was dug into the bottom of a deep pool in the river, draining the river for a 1 km section between the tunnel entrance and exit. The lack of flow through this section of river and the velocity of flow through the tunnel has meant fish access to 40% of the river has been blocked for over 100 years. The site is popular with tourists visiting the local historic mining towns and provides a spectacular sight of the river gushing out the side of a hill.
Reconnecting the river is a major technical and community engagement challenge. The solution needs to provide fish passage but also protect the heritage values of the site (which includes the tunnel and the river flowing through it), the natural landscape, and recreational values. Traditional hard engineered solutions are impractical because of these factors and the site’s remote location and rugged conditions.
This paper will provide an overview of the community engagement process and key learnings. It will also provide detail on the design of the highly innovative low-flow fishway that protects the natural, heritage and recreational values of the site.