[1] In 1814 the lagoon and its surrounding areas were used as a camp by a group of convicts led by Cox as they built the first road over the Blue Mountains.

In 2006, the Blue Mountains City Council commenced a lagoon restoration project, removing weed infestations.

The land was clear at the time, but has now returned to nature after work carried out by the Glenbrook Lagoon Society Bushcare group, Blue Mountains City Council and the Urban Runoff Control Program.

The lagoon and its surrounding area also provide an important natural sanctuary for native flora and fauna which is quite unique in the urbanised township of Glenbrook.

Without proper drainage of this water, significant environmental issues have risen including the growth of noxious weeds which have effectively choked out natural aquatic flora and fauna living in the lagoon.

These materials can include herbicides, fertilisers, Grey water use, oil and petrol, sediment, sewage, animal faeces, garden waste, litter and contaminants.

[3] The presence of The Cabomba and Salvina weeds in the lagoon posed a serious threat to native flora and fauna and also introduced the threat of the noxious weeds spreading into nearby waterways such as the Nepean river, Hawkesbury river and the many waterways within Blue Mountains National Park including catchments which lead to Warragamba Dam.

[9] In order to combat this threat during 2006 a $95 000 grant was given to the Blue mountains city council to commence work on re-generating the lagoon and removing the noxious weed Salvina.

[7] Regeneration efforts involved the mechanical harvesting of 200 tonnes of Salvina[7] and also the use of herbicide spot treatment with some hand removal of the remaining weeds.

[9] These declining oxygen levels where attributed to the large amounts of breakdown of the dead Cabomba weed matter caused by the use of the herbicide.

[9] To combat these declining dissolved oxygen levels Generators and pumps were brought to the lagoon attempt to re-oxygenate the water.

However these efforts produced limited results the task of re-oxygenating the lagoon proving to difficult with the little power supply to run the generators and pumps and noise complaints from local residents.

The hopes of this program were that it would be able to successfully monitor water quality, biodiversity and weed control outcomes of the lagoon.

[11] Bush-care groups continue regeneration work on the lagoon and its surrounding areas in hopes of restoring the natural environment to provide habitats for the native fauna and flora.

[11] Due to the dispersed nature of the regrowth of the Cabomba weed a large scale herbicide treatment would not have been effective.

[11] Regeneration efforts have also seen an increase in turtle and fish numbers in recent years, with many native species once again becoming self sustaining.

Recent surveys by Biosis have determined a rise in species such as the Fresh water catfish (Tandnus tandanus),[3] Australian Smelt (Retropinna semoni),[3] Flat-headed gudgeon (Philypndon grandiceps)[3] and long-finned eel (Angulla reinhardtii)[3] The Blue mountains council has worked with local bush care groups to augment habitats to form a natural environment that promotes the self sustaining nature of native fish and deters the survival of some noxious fish which were reported by biosis to be inhabiting the lagoon.

[12] These increases in aquatic species can be attributed to the removal of noxious weeds and upgrades to storm water treatment around the lagoon.

It is hoped that through these efforts the lagoon will remain as a healthy eco-system and will continue to be a sustainable habitat for native flora and fauna.