In 1899 a second barrier, known as the 'lower breakwater' was built further downstream on the river at the southern boundary of Reedy Lake, making it a predominantly freshwater wetland, with an extensive cover of vegetation, that supported diverse populations of waterbirds and other aquatic wildlife.

During the 1950s, 1960s and 1970s further works were carried out and refinements added, such as inlet pipes from the river above the lower breakwater and an outlet channel with a flow regulator, to maintain and control water levels in the lake.

The feeding behaviour of the carp undermined the reedbeds and increased water turbidity, leading to the death of submerged plants, decreased oxygen levels and the decline of small aquatic wildlife.

Other waterbirds with recorded counts of over 1000 at some time include the Australian shelduck, Pacific black duck, Australasian shoveler, grey and chestnut teal, purple swamphen, Eurasian coot, red-necked stint, sharp-tailed sandpiper, silver gull and whiskered tern.

Other species of which the lake is recorded as holding regionally high numbers are magpie geese, glossy ibis, brolga, Australian spotted crake, black-tailed godwit, marsh sandpiper, black-winged stilt, red-kneed dotterel and white-winged black tern.