Lake Richmond

Lake Richmond (Aboriginal Australian name: Naragebup) is a freshwater lake in Rockingham, Western Australia. It is approximately 1,000 m × 600 m (3,300 ft × 2,000 ft), with an area of 40 ha (99 acres), and is 15 m (49 ft) deep in the centre. It is believed to be named after the London borough.^[1] It is part of Rockingham Lakes Regional Park.

Lake Richmond
Lake Richmond from the look out tower
Lake Richmond
Location	Rockingham, Western Australia
Coordinates	32.286°S 115.715°E / -32.286; 115.715
Type	Lake
Basin countries	Australia
Western Australia Heritage Register
Designated	30 June 2017
Reference no.	18483

Overview

The lake is less than 1 km (0.62 mi) from the coast,^[2] having separated from the ocean at Cockburn Sound within the last 4,000 years.^[3][1]

The shallow waters within about 15 metres (49 ft)^[3][1] of the edges of the lake are home to thrombolites, estimated to be about six million years old.^[2][4] The internal structure of the thrombolites is believed to be unique in the world.^[3][1]

In 1996, the Western Australian Museum concluded that structures on the lake were likely to be tidal weirs constructed by pre-colonial Indigenous Australians for use as fish traps. They were given preliminary protection under the Aboriginal Heritage Act and the Djeran Fish Festival was subsequently organised as a celebration. However, the Department of Indigenous Affairs later concluded that they were not Aboriginal sites, following a review of aerial photographs and claims by a local resident that he had built the structures between the early 1960s and early 1980s.^[5]

Before 1960, the lake's salinity was 2000–3500 mg/L.^[a] In the 1960s it was used as part of an urban drainage scheme; the Water Board constructed inlet and outlet drains. Subsequently the salinity level dropped to 300–400 mg/L.^[6][1]

A boardwalk extends approximately 115 m (377 ft)^[b] into the lake.^[2][4]

Water birds that inhabit the area include the Australian pelican, black swan, Australian shelduck, musk duck, white-faced heron and common greenshank.^[4] The lake is home to the Swan River goby (Pseudogobius olorum), eastern mosquitofish, sea mullet, goldfish and yabbies.^[6][7]

The lake was used as a source of fresh water by the local indigenous Noongar people, as well as the settlers of the Swan River Colony.^[2][1]

The 10th Light Horse Regiment had a camp near the lake during the war years.^[1]

In 2017, the lake was given a permanent entry on the State Register of Heritage Places.^[8] It also listed on the WA Register of Aboriginal Sites, as RAS #15974.^[1]

Notes

1. less than 10% of seawater, which is typically around 35,000 mg/L.
2. Measured on Google Maps' satellite view, 16 August 2017.