A drainage basin is an extent of land where water from rain and melting snow or ice drains downhill into a body of water, such as a river, lake, reservoir, estuary, wetland, sea or ocean. The drainage basin includes both the streams and rivers that convey the water as well as the land surfaces from which water drains into those channels, and is separated from adjacent basins by a drainage divide. Major drainage basins are coded by hierarchy within the National Catchment Boundaries (NCB) dataset, with primary drainage basins attributed Level 1 and smaller river catchment subdivisions attributed Level 2. Beyond that, minor river and creek watersheds are ranked by the Pfafstetter Coding System. This article deals with surface water rather than groundwater basins, such as the Great Artesian Basin. Australia has twelve distinguished NCB Level 1 drainage divisions or thirteen after splitting the South East Coast division at the New South Wales–Victoria border as defined by the Australian Water Resources Assessment 2012, a hydrological survey conducted by the Bureau of Meteorology. Runoff from these divisions generally flows into the Pacific Ocean, the Indian Ocean, the Southern Ocean and Lake Eyre. List of NCB Level 1 drainage basins A New drainage basin codes assigned by the Bureau of Meteorology in 2010. Previous codes were labelled using Roman Numerals. See for details. B Long term average from July 1911 to June 2010 C The obsolete Australia River Basins 1997 survey listed the Bulloo-Bancannia drainage basin as a separate division, but has now been combined with the Lake Eyre Basin. D Known in Queensland as Gulf Basin List of NCB Level 2 drainage basins The following is a list of river or island catchments that are subdivisions of the basin containing them. North East Coast Jacky Jacky Creek Barron River Mulgrave-Russel Rivers Johnstone River Tully-Murray Rivers Cardwell Coast Hinchinbrook Island Herbert River Black River Ross River Haughton River Olive-Pascoe Rivers Burdekin River Don River Proserpine River Whitsunday Islands O'Connell River Pioneer River Plane Creek Styx River Shoalwater Creek Water Park Creek Lockhart River Fitzroy River (QLD) Curtis Island Calliope River Boyne River Baffle Creek Kolan River Burnett River Burrum River Mary River (QLD) Fraser Island Stewart River Noosa River Maroochy River Pine River Brisbane River Stradbroke Island Logan-Albert Rivers South Coast Normanby River Jeannie River Endeavour River Daintree River Mossman River See also List of reservoirs and dams in Australia List of