Above: Aerial Photographic map of Jumpinpin with two mouths and Swan Bay to the north. The south mouth later sealed over and the north mouth is still moving further north
Jumpinpin and Swan Bay
The most significant change to the Stradbroke Island in historic times occurred in 1896 when a combination of events revolving around a series of extreme storms, a cyclone and a shipwrecked load of dynamite all conspired to cause it to be cut in half when the Ocean waves broke through a narrow band of sand hills and the seas flooded into the waters of Morton Bay thus creating two islands, North Stradbroke and South Stradbroke. The place of the breakthrough, just south of Swan Bay, is called Jumpinpin, an Aboriginal word some people say means place of the honey suckle tree (giant banksia) and others say means “the place of the big waves” whichever is the correct translation for the record, it was called Jumpinpin long before the break though and there is no relationship between the name and “jumping”.
Old maps show Jumpinpin was a narrow neck of sand, so narrow that historian Thomas Welsby stated that a man standing with a foot in the waters of Morton Bay could throw a cricket ball across the sand dunes and make it land in the waters of the Tasman Sea. Maps and photographs of Jumpinpin show it was not more than 100 metres wide.
The events which led up to the Jumpinpin breakthrough seem to have begun with the shipwreck of the Scottish ship the Cambus Wallace, a 1,651 tonne 245 feet long iron hulled steamer, on her maiden voyage out to Sydney in .
Caught in a howling south easterly gale she ran aground amongst the breakers off Jumpinpin and was a total wreck in September 1895. Included in her cargo was a load of whiskey and an equally explosive load of dynamite. When customs officers arrived at the scene they found that most of the locals who were still sober enough to dig had focused on getting as many bottles of whisky as possible off the beach and buried in the sand hills as they could before the arrival of the officials; the dynamite was left alone where it was washed up. When things had settled down and the officers had gained control of the situation they had the problem of dealing with some 400 cases of water damaged dynamite which was deemed unstable. The dynamite was stacked in a hollow between the sand dunes and blown up. It was later reported that the explosion was heard and felt as far away as Cleveland. Needless to say an explosion of that magnitude on a sand barrier of less than 100 metres width had a significant destabilizing affect on the dunes. Also the massive bulk of the wrecked ship sitting in the water just off the beach where the currents often tear past at a rate of knots would have created significant erosion forces, making new channels and pushing currents into the beach. What ever the exact cause it can be no coincidence that six months later, in the Autumn of 1896 when the cyclones and storms always smash themselves against the beaches of South east Queensland, the waves cut through the narrow neck of Jumpinpin and opened the mouth of Swan Bay to the ocean.
Immediately to the north of Jumpinpin is Swan Bay. Now-a-days Swan Bay is separated from the Ocean by more than a kilometer of wide swaths of towering, mobile sand dunes and flat grasslands that in rainy times become shallow lakes.
At the time of the breakthrough this was not the case, there was only a narrow neck of sand less than a hundred metres wide and so low as to allow waves from the ocean to wash over into Swan Bay.
A cursory study of the land forms that surround Swan Bay, particularly to the immediate north show that the ocean dunes were once a much wider barrier between the sea and the swamp and that high and stabile dunes with a significant open forest form of vegetation stretched out east over what is now the ocean. It is also evident by studying the obvious connection between Freshwater Creek and Never Never Creek that what is now Swan Bay was once just a wide part of the 18 Mile Swamp through which this “Freshwater/Never Creek wound to empty westward into Canaipa Passage just south of Slipping Sands: that at some time Swan Bay was carved out of the Swamp, probably by the combined action of the Rivers and the Ocean during a period of extended high rainfall after which the Bay remained open to the ocean for a considerable time, probably even at the time of Cook’s passing in 1770 thus easily explaining how a ship could end up in the Swamp(refer Cook’s maps which show Swan Bay open to the ocean).
In the 19th century Swan Bay was much deeper than it is now and its entrance was at the east side of the bay. It was a popular destination for holidays and fishing trips and yachts of some size could easily sail into the Bay and moor in its deep and sheltered waters.
After the break through erosion moved the mouth of the bay to its west side next to the mouth of Never Never Creek and the bay gradually filled with sand to become shallow and unnavigable except on the high tide and then only for boats with a shallow draft. In 2002 a huge southerly storm cut through the sand bar at the east side of Swan Bay and, combined with heavy rainfall that filled the Swamp and poured out of Freshwater Creek into Swan Bay the mouth has moved back to the eat side and the mouth of Never Never Creek has all but silted over.
Swan Bay is now a fish habitat and all forms of fishing are banned there. It is full of a wide variety of fishes but its stingrays are amazing and prolific and in most seasons a there are still small flocks of black swans to be seen.
Aerial photograph of Jumpinpin moves slowly north eating into Swan Bay and filling it with sand, note widening of dune area that separates Swan Bay from the Ocean
This is an old map of the Jumpinpin breakthrough drawn in 1912, note the narrow neck separating Swan Bay from the sea and the fact that Jumpinpin has moved slowly northwward over the years.
In the 'e' book there is a large collection of old maps of Jumpinpin
Jumpinpin and Swan Bay in 1970, note how much things can change over a few short years.
Early maps and oral histories tell us that the sand bar between Swan Bay and the Ocean was only very narrow and at high tide, in big seas, the waves would wash over into Swan Bay.
The map drawn by Dr. Young's Grandfather shows a "submerged forest" growing out into the waves on the ocean beach in about 1920, clearly the shape of this section of shore line has been altered enormously in the last several hundred years. Most likely this is the result of minor sea level fluctations over teh recent centuries