The Barwon River is a perennial river. Some of the townships the Barwon runs through are; Forrest, Barwon Downs, Birregurra, Winchelsea, Inverleigh, Geelong, Ocean Grove and Barwon Heads
It's source is from the Otway Ranges. It's length is 160 km (99 mi) and the basin is 8,590 km2 (3,317 sq mi)
The river's name is derived from the Aboriginal word Barwon, meaning "magpie" or "great wide". In the Australian Aboriginal Wathawurrung language, the names for the river are Worragong, with no clearly defined meaning; Nellemengobeet, meaning "lagoon at mouth"; and also Barrwang, meaning "magpie".
The Barwon River is fed by the confluence of the east and west branches of the river, the Barwon River rises in the Otway Ranges and flows generally north by east and then east, joined by thirteen tributaries including the Leigh and Moorabool rivers and flowing through Lake Connewarre, before reaching its mouth and emptying into Bass Strait at Barwon Heads. The river flows adjacent to the settlement of Winchelsea and the city of Greater Geelong. The estuarine section of the river forms part of the Port Phillip Bay (Western Shoreline) and Bellarine Peninsula Ramsar site as a wetland of international importance, as well as of the Bellarine Wetlands Important Bird Area. From its highest point including its source confluence, the river descends 295 meters (968 ft) over its 160 kilometer (99 mi) course
Millions of years ago, the landscape surrounding the Barwon River looked rather different to what it does today. The formation of the Barwon dates back as far as the Cretaceous period (70-145 million years ago) when Australia separated from the super-continent Gondwanaland and dinosaurs still roamed Earth. During this period, sedimentary rocks were laid down which can still be seen to the south of the Barwon as rocky outcrops in some places. They also lie off the coast of western Victoria in the Otway Basin.
As recently as 40 million years ago, much of the land through which the Barwon now flows was covered by a wide sea. Early streams flowed from the higher ground of the Otways, northwards to the sea and limestone deposits formed along this ancient coastline.
Along the river you can see the Belmont escarpment overlooking Barwon Valley and the Jerringot Wetlands is one such limestone outcrop, formed between 25 and 30 million years ago, which extends from a large deposit at Waurn Ponds towards Corio Bay.
More recently, during the Miocene period (7-23 million years ago) a series of plate movements and volcanic eruptions saw the coastline extending as far inland as the town of Meredith and the estuary of the Barwon located at Belmont Common. At this time, much of the present course of the Barwon lay under the sea with only a few nearby features such as the ancient granite of the the Dog Rocks at Batesford protruding above the water's surface to form small islands. It was this sea which deposited the limestone which can be found in the Batesford-Fyansford area and which was quarried for use by the Fyansford Cement Works throughout the 20th century. At around the same time, clay and other materials laid down combined with the Batesford Limestone to produce a band of sedimentary rock running down as far as the eastern fringes of Lake Connewarre. This is known as the Fyansford Formation.
Granite
Continuing plate movement throughout the Miocene period affected the various fault lines around the Geelong region such as the Bellarine Fault, causing the Bellarine region to lift and then around 20 million years ago, the sea to withdraw, uncovering the land and the current course of the Barwon.
Subsequent sea movements in the early Pliocene period (3.5-5 million years ago) resulted in the formation of a shallow bay between Torquay and Ocean Grove, covering the lower reaches of the Barwon once again and led to the deposition of shell beds which now lie under this part of the river including Lake Connewarre and surrounds. Sedimentary deposits across the region including the Bellarine Peninsula at this time produced what is called the Moorabool Viaduct Formation. In places it lies over the top of the Fyansford Formation.
It was also around this time that the movement of fault lines pushed the Cretaceous rocks of the Otway Ranges to their current height, giving the Barwon the strength to carve a path to the sea through new lava flows which occurred in the later Pliocene era.
It was at this time that volcanic activity around Mt. Duneed, Mt. Moriac and Mt. Pollock led to further changes in the river and the landscape. Until about 2 million years ago, the Barwon followed a course which saw it flow through a gap in the Barrabool Hills south of Lake Modewarre, then down a valley adjacent to the hills before reaching Fyansford. Around 2 million years ago, lava flows north of Inverleigh blocked this course, causing the inundation of the land to the west of Winchelsea before the river once again carved a new path to the sea. The lava flow followed the old riverbed, leaving a deep basalt deposit in this area and contributing to the wide basalt plains which extend across the region, providing extensive farming land today.
European settlers were quick to see the value of these basalt deposits, establishing bluestone quarries along the banks of the Barwon River. It is this rock which can still be seen in the stonework of many historical homesteads and buildings across the region - the Barwon Paper Mill and its water race being an example. Naturally, this quarrying made a lasting impact on the river surrounds. This is particularly noticeable along the walking track to Baum's Weir where the quarrying exposed the Pliocene basalt, leaving high, rocky escarpments which tower over the river below.
At the same time, these lava flows extended out into the bay with three branches forming which dammed the lower Barwon in several places and created a number of lagoons - including a lake at Queen's Park, with another blockage below the Belmont Escarpment.
In addition to the various geological and environmental events which shaped the course of the river, across millions of years, continuous erosion and subsequent sedimentation have also influenced the soil of the region, forming the land we see today.
Barwon Weir
Q1 The listed coordinates will bring you to the Barwon Weir. Describe the rock area behind you when your facing the river.
Q2 WP2 will take you to a sign along the walking track. What did the early settles source from the river above?
Q3 WP3 will bring you to the view of the 'pool'. Describe the water at this location. (slow moving / still / rapids ect.)
Q4 The final WP will bring you to a walking path along the river, near the paper mill. Describe the escarpment on the opposite side of the river. How big are the rocks there?(small, medium, large, massive)
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