The Ovens River is set to benefit from a $5.1 million investment through the Victorian Government’s Building Works stimulus package to commission a Rock Ramp Fishway at Goulburn-Murray Water’s Tea Garden Creek Weir at Everton, and a Vertical Slot Fishway (VSF) at Alpine Shire’s Bright Weir. This will remove two of the three barriers to fish movement remaining in the Ovens, opening almost 400km of riverine habitat between the River Murray and the Ovens Headwaters.
How it works
The first significant barrier to fish movement down the Ovens River is the Bright Weir that forms the popular Bright swimming hole. In the Bright area, the Ovens River is relatively shallow, clear, and fast flowing. The fish community is dominated by an abundant population of the exotic Brown and Rainbow trout with populations of native species including River blackfish, Two spined blackfish and Mountain galaxias. There are small numbers of Murray cod and Trout cod in the upper Ovens reach, however the abundance is much higher downstream of Myrtleford along with a sizeable population of Macquarie perch.
The Bright Weir with boards in place to create the upstream swimming hole
The third barrier to fish movement along the Ovens River is the Tea Garden Creek weir at Everton. The Tea Garden Weir supplies the Tea Garden Creek with a gravity fed water supply for irrigation and stock and domestic use in Markwood, Millawa and Oxley, where it flows into the King River. Restoring fish passage at Tea Garden weir will provide small, medium and large bodied native fish with the opportunity for unimpeded migration to upstream and downstream habitats between the River Murray and Porepunkah, including the Buffalo and Buckland Rivers. This will strengthen the populations of Murray cod and the endangered Macquarie perch and Trout cod that are present in strong numbers in this stretch of the Ovens, increasing the resilience of the entire population throughout the Murray-Darling Basin.
The Tea Garden Creek Weir at Everton
The second barrier is the Porepunkah weir, which will remain as the only barrier to fish passage in the Ovens River. NECMA has commissioned a Detailed Design for a Vertical Slot Fishway that awaits funding for its construction.
Eighteen native fish species have been recorded in the Ovens River. Eleven are of conservation significance in Victoria or at a national level, and five of these, Murray Cod (Maccullochella peelii), Trout Cod (Maccullochella macquariensis), Macquarie Perch (Macquaria australasica), Silver Perch (Bidyanus bidyanus), and Flat-Headed Galaxias (Galaxias rostratus) are EPBC Act listed. With the construction of the Vertical Slot Fishway (VSF) at Bright and the Rock Ramp Fishway at Tea Garden Creek Weir, year-round passage will be provided for these species to migrate to habitats upstream and downstream.
Most native species undergo up and downstream migrations as an important component to their life history, usually triggered by low and rising flows. Late winter, spring and summer are the most important times for fish movement with Trout cod, Murray cod and Macquarie perch expected to migrate upstream during spring, especially on a rise in flow. Following spawning, larvae will drift downstream to new habitats. Further downstream migration can include displacement during high flow events with a return upstream migration once the flow event has passed.
Species such as River blackfish, Two-spined blackfish and the small-bodied Galaxias make localised movements (000’s metres) and are considered ‘non migratory’. However, all species will make downstream migrations to escape from poor water quality or ash flow events and will often recolonise these impacted areas upstream when water quality returns, usually over several years.