The lake, situated on a Holocene beach ridge, was once connected to the sea and was formed approximately 6,000 to 7,000 years ago. Within the lake, Holocene nonmarine microbial structures, reported as either stromatolites or thrombolites, have been found.[2]
Like Lake Cooloongup, Lake Walyungup is thought to be drying because of reduced rainfalls. Depths of both lakes fluctuate from as little as 0.5 to 3.5 metres, with the permanent pools of Lake Walyungup being the deepest points. Both lakes are also increasing in salinity which Walyungup being more saline than Cooloongup. Unlike Lake Cooloongup, which has a groundwater outflow towards the sea, Lake Walyungup is a closed system, with water from the lake discharging through evapotranspiration only. Both lakes have small freshwater wetlands on their western edge, which is made up of dunes, while the eastern edge is formed by a limestone ridge.[3]
A warning sign at Lake Walyungup highlighting the risk of unexploded ammunition
The Lakes Cooloongup and Walyungup continue to be of spiritual significance for the local indigenous population as the place where the Sea Waugal laid her eggs. Cooloongup, in the Nyungar language, means "place of children", leading to the conclusion that the northern lake was a place for children while the southern one was for adults.[3]
A survey in 2005 found that the lake predominantly attracts local visitors, which over 80 percent of the visitors living locally.[3]
Lake Walyungup as well as Lake Cooloongup, Port Kennedy Scientific Park and Lark Hill, all within Rockingham Lakes Regional Park, are potentially contaminated with Unexploded Ordnance, having been used as artillery range by the Department of Defence in the era around World War II.[3]
