“Remember this spot,” Blaxland might have told Wentworth and Lawson. This is Glenbrook Lagoon. It sits at the foot of the Blue Mountains. This lagoon is more than just a scenic waterhole. It is a heritage-listed site.
Glenbrook Lagoon is a natural flat-bottom freshwater lagoon. It has an average depth of 2.7 metres. The maximum depth reaches 4.05 metres. The lagoon covers an area of 7 hectares. It relies on water flow from the surrounding area. Natural springs also feed the lagoon. Glenbrook Lagoon is one of only three lagoons of this kind in the Hawkesbury area water catchment.
Glenbrook Lagoon’s story stretches back to 1813. William Lawson, William Wentworth and Gregory Blaxland found it. They crossed the Blue Mountains. Blaxland described it as a large lagoon of good water. It was full of very coarse rushes.
In 1814, convicts camped here. Cox led them as they built the first road over the Blue Mountains. Governor Macquarie later used it as a military depot. They checked travellers’ permits to cross the mountains.
Later, a depot opened at Springwood. The Glenbrook Lagoon depot became less important. The lagoon was still a vital water source. Horses and travellers welcomed it. Early trains even used the water to cool their engines. Today, wetland birds call this lagoon home.
The Ellis family once lived near Glenbrook Lagoon in the 1940s. They ran an orchard. The land was clear then. Nature has since reclaimed it. The Glenbrook Lagoon Society Bushcare group helped. You can find the remains of their cottage 100 metres north of the lagoon.
Glenbrook Lagoon has served many purposes. It was a military depot. It supplied water to the Zig Zag railway system from 1867 to 1913. The eastern side was dammed to enlarge it. This provided more water for the railway. The dam wall is now Glenbrook Road. It was once Railway Street. In the 1860s, it provided drinking water for Glenbrook’s residents.
Today, Glenbrook Lagoon is a tourist attraction. People also enjoy bushwalking here. It is a natural sanctuary for native flora and fauna. This is unique in urban Glenbrook. Helicopters even use the lagoon to fight bushfires. They collect water to douse the flames. This happened in 2001, 2013 and 2017.
The lagoon is culturally significant. Locals swam and fished here. The Zig Zag railway relied on it. Glenbrook Lagoon holds historical importance for the Blue Mountains.
Eucalypt and Angophora Costa trees surround the lagoon. These trees are unique to this area. Peron’s Tree Frog lives here. Rushes and fallen logs offer habitats for wetland birds. Swamphens thrive here. These plants protect frogs. Striped Marsh Frogs and Eastern Dwarf Tree Frogs live here. Native Bladderwort floats on the surface providing foraging habitat.
Damming the lagoon caused pollution. It became a closed water system. Pollutants couldn’t flush out naturally. Stormwater carries chemicals and waste into the lagoon. This encourages noxious weeds. Cabomba and Salvinia weeds deplete oxygen. This harms native plants, fish and turtles.
In 2006, the Blue Mountains City Council started a restoration project. They removed 200 tonnes of Salvinia. They used herbicide spot treatment. In 2012, they removed Cabomba weed. The herbicide Carfentrazone-ethyl killed it. Some fish died due to oxygen depletion. Generators tried to re-oxygenate the water.
Regeneration efforts have decreased Salvina by 99%. A 2014 survey found no Cabomba. However, it regrew in 2017. Scuba divers removed it by hand. Turtle and fish numbers have increased. Freshwater catfish, Australian Smelt and long-finned eel populations are rising. The Eastern Long-necked turtle and Sydney basin turtles are breeding successfully. Aquatic insects are also increasing.
A secondary Cabomba Weed Control Program is in place. It monitors water pollution. It removes any regrowth of noxious weeds. Glenbrook Lagoon is now a healthy ecosystem. It is a sustainable habitat for native flora and fauna. Glenbrook Lagoon stands as a testament to nature’s resilience. It highlights the importance of community action.