It’s a weir that looks nothing like a weir, and it’s proving to be a win win for the Bega Valley Shire’s northern water supply and the Brogo river wildlife.
The new weir will allow migrating Australian bass to get back into the dam, thereby greatly enhancing the native fishery and potentially the size of fish caught.
The project started with Bega Valley Shire Council’s water services team working with NSW Fisheries and an environmental consultant to redesign and replace an ineffective shingle weir downstream of the Brogo Dam.
Bega Valley Shire Council’s manager of water and sewerage services, Jim Collins said the old weir stood in the path of migrating fish species and it required frequent maintenance following heavy downpours.
“When designing the new weir we needed to satisfy operational, environmental and aesthetic criteria,” he said. “We basically needed the weir to provide a water level high enough for the pumps that service the Bermagui, Quaama and Cobargo areas, while providing a way through for migrating river wildlife, and for it all to blend into an area of significant natural beauty.
“The solution came with a design that looks nothing like a conventional weir, choosing instead a stepped rock ramp arranged in four rows across the main flow path. Construction has just finished and we couldn’t be happier with how the new weir looks and works.
“One of the big problems with the old weir was the constant need for repair following significant rainfall. After each heavy storm council workers were required to wade into the river and reconstruct the weir by hand from salvaged rocks washed away in the storm.
“The new weir uses boulders that weigh at least a tonne, and the new structure blends into the river, allowing grayling, Australian bass and other native fish to easily access the upstream habitat.
“This project has provided a much needed solution that compliments work underway at the other end of the system with construction of a four-million-litre reservoir to service the Bermagui area,” Mr Collins said.
Far South Coast Bass Stocking Association times its annual release of bass into Brogo Dam with the gathering of bass fisherman gathered for its annual Brogo Bass Bash competition.
The association has for the past 18 years used the proceeds from the Bash to purchase up to 20,000 bass each year, which are released into the dam along with yet more stocked by Fisheries.
These fish released in Brogo Dam are known to escape over the spillway in times of flood into the Bega River thereby creating some excellent bass fishing downstream all the way to the where the river turns into an estuary.
But up until now there was no way unfortunately for the escapees to get back into the dam on the migration back upstream after spawning in estuarine waters down closer to the coast.
The new weir will change all of that and should greatly improve the fishery and size of fish caught.