NOT many people would see a dry riverbed as a good thing, but Inland Waterways OzFish were recently involved in a project that took full advantage of the situation. The team, with funding from the NSW Environmental Trust and some assistance from NSW DPI – Fisheries, were able to remove a redundant weir in the Narran River near Lightning Ridge. The decades old barrier to fish movement was no longer needed by the landholder, who was willing to retire their license and have the weir removed.
Removing a weir requires approval to use plant and equipment in sensitive riparian and aquatic areas. It is also an extremely difficult task to undertake when water is flowing over such structures and can add weeks or even months to a project. The dry conditions allowed an excavator to be driven into the bottom of the normally wet channel which dramatically simplified the process of removal. Working in this way saved time and reduced the environmental impacts, with the removal completed in just a few days.
Barriers such as this weir are identified as a Key Threatening Process- they prevent the migration of native fish species and can’t have severe implications for these populations. In extreme cases barriers can result in localised extinctions.
The removal of the weir has returned fish passage to 46 km of important fish habitat.
More information on threats to native fish habitat can be found at dpi.nsw.gov.au/fishing/habitat/threats
