Manly Lagoon

The Restoration of Manly (Queenscliff) Lagoon manlylagoon

"You may - if you have any soul within you, you always must - halt a while in the centre of the bridge, and look long and lovingly up the lagoon. It is a fair perspective always, but most divine on an afternoon with the sun well down the hills, and a silvery light upon all the broadwater."
- Francis Meyer, 1880, "Beautiful Manly"

Manly Lagoon is a shallow coastal lagoon 12 kilometres north-east of the Sydney Central Business District. The water body of the lagoon has a surface area of 13 hectares and extends 3 kilometres west and north from the lagoon mouth on Queenscliff beach. The lagoon has a catchment of 1800 hectares consisting of 3 sub-catchments drained by the major creeks including Burnt Bridge Creek, Manly Creek and Brookvale Creek.

Once an unspoilt coastal wetland, and only 30 years ago a swimmable waterway providing fish habitat and numerous recreational opportunities, Manly Lagoon is now 10% of its original size and is considered one of the most polluted recreational waterways in NSW. Swimming, boating and fishing are banned due to polluted water and sediment.

Manly Lagoon Estuary Management Study, 1995: "The water of the lagoon is eutrophic (oxygen depleted) and sensitive to further increases in nutrient inputs ... Manly Lagoon sediment is contaminated with heavy metals and, compared with Sydney Harbour or Curl Curl Lagoon, has the highest average levels of copper and lead ... Indigenous vegetation is severely depleted... as such, any areas of remnant vegetation should be maintained and conserved as a valuable resource."

Additional Resources:

Vegetation

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.

Last modified on Wednesday, 19 June 2013 09:39

Aquatic Flora and Fauna

There is little habitat for aquatic life because:

The natural vegetation of the lagoon has been greatly modified by urban development and the spread of introduced plant species.
There are no saltmarshes or mangroves and only very small amounts of seagrass which fringe the shoreline in the lower reaches of the lagoon.

Last modified on Wednesday, 19 June 2013 09:39

Environmental Flows and Water Extraction

Weirs:

on Manly Creek to water Warringah Golf Course
on Burnt Bridge Creek to water Balgowlah Golf Course

Bore: to water Manly Golf Course

Manly Dam: to water Wakehurst Golf Course

Last modified on Wednesday, 19 June 2013 09:40

Eutrophication or Rehabilitation?

Reversing the Dead-End Trend ....
The Manly Lagoon Estuary Management Study (1995) states that:

The water of the Lagoon is EUTROPHIC and sensitive to further increases in nutrient inputs.
Manly Lagoon sediment is CONTAMINATED with HEAVY METALS and, compared with Sydney Harbour and Curl Curl Lagoon, has the highest average levels of copper and lead. The concentrations of heavy metals in the muddy surface sediments of the lagoon appear to have increased significantly over the period l985 to l993. On the available data, concentrations of lead, mercury and zinc exceed overseas sediment standards (Washington, USA) over much of the lagoon.
There are 29 Sydney Water sewer overflows in the catchment.

Last modified on Wednesday, 19 June 2013 09:40

Physical Changes

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.

Last modified on Wednesday, 19 June 2013 09:40

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