Johnson Swamp received a partial fill in autumn 2015 to prime conditions for a spring top-up that occurred between late September and mid October 2015.
The top-up was delivered at a steady rate with the aim of promoting an increase in aquatic plant biomass, providing an abundance of food for waterbirds, frogs and turtles. The event was also carefully managed to ensure a brolga nest discovered in September 2015, was not drowned or damaged.
In late November 2015 a second top-up was delivered to maintain a stable water height in response to the presence of at least seven male Australasian bittern, a nationally listed species.Further monitoring including an active and acoustic dawn and dusk survey, revealed that individuals were displaying breeding behavior (including a possible bittern nest sighting) and that the wetland was also supporting threatened Australian little bittern. The North Central CMA continued to deliver environmental water to Johnson Swamp until the 3 February 2016 to maintain water levels and enable the nesting bitterns to successfully fledge their young.
A gradual drawdown was then facilitated to provide optimum foraging conditions for juvenile bittern and brolga and encourage migratory species such as sharp-tailed sandpiper and threatened Australian painted snipe to feed on the exposed mudflats of the wetland.