The evolution of Jumpinpin Inlet - OzCoasts

The evolution of Jumpinpin Inlet
Salter (1985) adds that alteration to currents and tides also resulted in erosion of the
southern end of South Stradbroke. The author states that the greatest washout
occurred in 1938, when the sea broke through at the southern point of South
Stradbroke, creating an island the locals called “Tragedy Island”. In 1952 a further
episode of accelerated beach erosion was observed at South Stradbroke. As reported
in the Courier Mail (13.9.1952), 200 yards eroded in one month.
With the onset of World War II the military began photographing the coast. Aerial
photographs of Jumpinpin were found from 1944 onwards. More recent changes to
Jumpinpin have been analysed from these aerials and are summarised in Chapter 8.
7.3 Summary
• South Passage, Southport and Jumpinpin were probably closed in 1770 as
recorded by Captain Cook.
• South Passage was observed open in 1799 by Flinders.
• Southport observed open in 1823 by Oxley.
• Jumpinpin opened either 1896 or 1898. The break divided the Isle of
Stradbroke into North Stradbroke (68 000 acres) and South Stradbroke
(5 200 acres) islands.
• Opening of Jumpinpin in the 1890s noticeably impacted the intra coastal
system. Redirection of tidal flow towards Jumpinpin in the early 1900s
resulted in silting of the broadwater, and erosion of the bay islands and the
southern extremity of South Stradbroke Island.
• It was initially thought that Jumpinpin had closed by 1917 and reopened in
1936. It is concluded that an inlet did exist in 1917 to the south of the original
one. The implication is that the original inlet migrated northward and closed
after the second (southern) inlet breached.
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