Northeast coast drainage division
BIRD: linking the biodiversity community
The northeast coast drainage division is the long, narrow area of Queensland between the Great Dividing Range and the Pacific Ocean. It is bounded at the north by Torres Strait, and in the south by an arbitrary line drawn along the Queensland - New South Wales border.
The division includes a wide variety of landforms and habitat types. Average rainfall varies from about 500 mm in the driest sections (notably the area surrounding Townsville) to almost 4 metres in the wettest districts. Most rain falls in the humid summer months, even in the relatively temperate south.
Rivers tend to be short but have high flow volumes, particularly during the wet season. On a per-area basis, the northeast coast division is the wettest of any in Australia. Major streams of the division (from south to north) include the Brisbane, Mary, Burnett, Fitzroy, Burdekin, North and South Johnstone, Mulgrave, Barron, Daintree, Bloomfield, and Normanby Rivers.
North of Cooktown and the Normanby River system, the watershed is only a few tens of kilometres from the coast, and the country is a mixture of relatively dry forest and extensive seasonal lagoon systems which support water birds in vast numbers. Cape York itself is very close to New Guinea, both in space and time — New Guinea is only another 150 kilometres or so north, and the shallow Torres Strait was dry land as recently as 7000 years ago. Not surprisingly, the flora and fauna of Cape York is very like that of southern New Guinea: the Cape has dozens of bird species not found elsewhere in Australia, several mammals more typical of New Guinea, and the rivers of the northeast coast contain nearly all of the 35 species of freshwater fish shared between Australia and New Guinea.
The section between Cooktown and about Innisfail includes the highest mountains in Queensland, and in consequence the highest rainfall areas in Australia. In sharp contrast, the area from a little north of Townsville as far south as Bunbaberg is relatively dry, with yearly average rainfall often in the 1000 mm range.
|— The Australian drainage divisions —|
|Indian Ocean||Timor Sea||Gulf of Carpentaria||Northeast coast|
|Western Plateau||Lake Eyre Basin||Murray-Darling Basin||Bulloo-Bancannia|
|Southwest coast||South Australian gulf||Tasmania||Southeast coast|