Great Sandy Strait

The Proud and Mighty Mary

The Catchment

The Mary River Catchment covers an area of approximately 9600 square kilometres, as the river winds 310 kilometres from Maleny in the sunshine coast hinterland, to the Great Sandy Strait. Rising at Booroobin, west of Caloundra, it flows north through the towns of Kenilworth, Gympie, Tiaro and Maryborough, before emptying into the strait. The major tributaries of the Mary include Obi Obi Creek, Yabba Creek, Wide Bay Creek and the Susan River.

Annual rainfalls in the catchment range from 2000mm in the headwaters to around 1200mm near Maryborough. The average discharge of the Mary into the Sandy Strait is 2300 GL per year. Large inputs of fresh water and sediment also occur during flooding on a more or less annual basis (ANCA 1996). Smaller though still significant inflows result from the Susan River and a number of smaller creeks of which Kauri Creek is the largest on the western side of the Strait.

Water exchange rates with the open ocean are rapid, owing to the presence of a deep main channel and the absence of mobile, unstable sand bars. In the estuarine conditions of the strait the inflow of fresh water from adjacent catchments can create prolonged conditions of low salinity. This is particularly true of the Mary River mouth. The outflow from the Mary and other major streams has a substantial influence on the water quality of the Great Sandy.

Endangered Inhabitants

The Mary River is home to a number of endangered aquatic species, including the Mary River Turtle (Elusor macrurus), the Queensland Lungfish (Neoceratodus forsteri), the Mary River Cod (Maccullochella peelii mariensis), the Giant Barred Frog (Mixophyes iterates) and the Cascade treefrog (Litoria pearsoniana). The threatened lycaenid butterfly, ot Illidge’s ant blue (Acrodipsas Illidgei) occurs in mangroves around the mouth of the river.

¨ ‘Threatened Fauna of the Mary River Catchment’ … click here

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Celebrating and Defending the Great Sandy Strait

It is not easy to summarise a history like the Mary’s. Many a contrasting tale of prosperity, hardship and massacre can be sifted from her muddy depths. ourgreatsandy will no doubt dredge up a few in later updates and these will be found under the Cultural Heritage link.

So who was this Mary person? In full, she was Lady Mary Lennox, wife of the Governor of New South Wales, Charles Augustus Fitzroy, who officially named the river in her honour in 1847. Prior to this time the system had been called ‘Wide Bay’ River by European Settlers. For countless millennia before that, however, it was known to indigenous tribes of the region by a variety of names, including Booie, Numabulla, Mooraboocoola, Moonaboola, and Moocooboola.