| Broken Bay | |
|---|---|
 Aerial photograph showing the mouth of Broken Bay as it flows into theTasman Sea, as seen looking across Sydney'sNorth Shore andNorthern Beaches | |
  Broken Bay | |
| Location | Central Coast,New South Wales,Australia |
| Coordinates | 33°34′07″S151°19′00″E / 33.56861°S 151.31667°E /-33.56861; 151.31667 |
| Type | Bay[1] |
| Primary inflows | Hawkesbury River,Brisbane Water,Pittwater |
| Surface area | 17.1 km2 (6.6 sq mi) |
| Average depth | 9.8 m (32 ft) |
| Water volume | 0.17 km3 (0.041 cu mi) |
| Islands | Lion Island |
| Website | NSW Environment and Heritage webpage |
Broken Bay, a semi-maturetide-dominateddrowned valleyestuary,[1] is a large inlet of theTasman Sea located about 50 kilometres (31 mi) north ofSydney on theCentral Coast ofNew South Wales,Australia; being one of the bodies of water that separate greater Metropolitan Sydney from theCentral Coast. Broken Bay is the first major bay north ofSydney Harbour in the state capital ofSydney.
Broken Bay has its origin at theconfluence of theHawkesbury River,Pittwater, andBrisbane Water and flows openly into the Tasman Sea.
The total surface area of the bay is approximately 17.1 square kilometres (6.6 sq mi).
The entrance to Broken Bay lies between the northernBox Head andBarrenjoey Head to the south. Barrenjoey Lighthouse was constructed in 1881 to guide ships away from the prominent headland. The bay comprises three arms, being the prominent estuary of the Hawkesbury River in the west, Pittwater to the south, and Brisbane Water to the north. These three arms areflooded rivers (rias) formed at a time when thesea level was much lower than it is at the present day.
The Hawkesbury River flows from the confluence of theGrose andNepean Rivers at the base of theBlue Mountains.
Pittwater extends south from Broken Bay and is the northernmost extent of the greater Sydney area. Pittwater's calm waters make it a popular sailing area. West Head, west of Barrenjoey Head, marks the divide between Pittwater and the Hawkesbury.
Brisbane Water is the northern arm of Broken Bay and has the towns ofGosford andWoy Woy on its shores.
Lion Island, named for its profile's resemblance to aSphinx from some viewpoints, is located at the entrance of Broken Bay. Lion Island Nature Reserve covers the entire island, and is home to a colony offairy penguins.
James Cook recorded "broken land" seen north ofPort Jackson just before sunset on 7 May 1770, and named it Broken Bay. However, there has been some controversy over whether what is now known as 'Broken Bay' was what was sighted by Cook.
Ray Parkin in his bookH. M. Bark Endeavour claims that the modern 'Broken Bay' was passed unremarked at night, and that Cook was in fact referring to the area aroundNarrabeen Lagoon.[3]Matthew Flinders placed Cook's 'Broken Bay' at 33° 42' South, near to the mouth of Narrabeen Lagoon.[2]
Whatever the case,Governor Phillip was the first non-Indigenous person to examine the present day Broken Bay in a longboat from theSirius on 2 March 1788.[4]
On 28 November 2005, documentary film-maker Damien Lay claimed that the wreckage ofM-24, aJapanesemidget submarine involved in theattack on Sydney Harbour in 1942 and disappeared soon afterward, was buried under sand on the seabed, just east of Lion Island. Lay claimed to have confirmed that copper wiring found at the site was consistent with that used in similar Japanese vessels.[5] A few weeks later,New South Wales Planning MinisterFrank Sartor announced that sonar scans conducted by the New South Wales Heritage Office at the location specified had found no trace of the lost submarine.[6]
M-24 was eventually found approximately 13 kilometres south of Broken Bay, 5 kilometres offBungan Head, proving the hypothesis thatM-24 chose to not draw attention to its mother submarines to the south of Sydney Harbour and instead moved north towards Broken Bay.[7]
Hawkesbury River region, New South Wales, Australia | |||||||||
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