FISH populations could increase now they will be able to move freely between Lake Callemondah and salt water in Police Creek.
A $117,000 rocky passageway will be built to allow fish to move from one pool to another over the existing two-metre concrete barrier.
The funding comes from the Fitzroy Basin Association, and the land is owned by the Natural Resources and Mines Department.
"There's not enough instances throughout the year where the water can flow over the causeway and provide passage for fish," Fitzroy Basin Association project officer Kelly Smith said.
Species such as barramundi, sea mullet, mangrove jack and pacific blue-eyes need both fresh and salt water to breed.
Ms Smith said hopefully the passage would be finished by October, and would lead to increased fish populations while raising community awareness of the importance of healthy wetlands.