The North Head Sewage Treatment Plant is surrounded by National Park and the largest area of bushland in Sydney Harbour, a large area of Threatened Eastern Suburbs Banksia Scrub borders the plant and a Threatened Population of Long-nosed Bandicoots is found in the grounds.
The indigenous vegetation communities originally associated with Manly lagoon and its tributaries have been heavily altered by urban development. There has been widespread introduction of ornamental exotic species such as Coral Trees which seasonally contribute very substantial amounts of leaf matter into the tributaries and the lagoon to the detriment of water quality. Weed infestations are common throughout the area, particularly where maintenance is less intensive, detracting from the water quality, habitat value and recreational amenity of the waterways.
There is little habitat for aquatic life because:
Reversing the Dead-End Trend ....
The Manly Lagoon Estuary Management Study (1995) states that:
Development within the Manly area became rapid following completion of the Sydney Harbour Bridge in l932. All suitable residential areas were quickly taken up and market gardens sprang up along the creeks, which fed into the lagoon in North Manly and Brookvale.