Application of a new river classification scheme to Australia's tropical rivers

Abstract

A revised typology of Australian tropical rivers was applied to the complete channel network (named and major rivers) shown on 1:250 000 topographic maps for three large drainage basins in northern Australia (Daly River, NT; Fitzroy River, WA; Flinders River, Qld). Reach mapping and classification were conducted using the revised typology. The 12 major river types proposed were: (1) bedrock rivers; (2) bedrock‐confined and ‐constrained rivers; (3) low sinuosity (straight) rivers; (4) meandering rivers; (5) wandering rivers; (6) anabranching rivers; (7) chains of ponds; (8) gullies; (9) floodouts; (10) lakes, swamps, billabongs and wetlands; (11) non‐channelized valley floors; and (12) estuarine rivers. The 12 major river types were developed based on river reach mapping for more than 264 000 km2 of tropical Australian catchments. At scales larger than 1:250 000, subdivision of each major river type is recommended. In the Daly and Fitzroy catchments, confined and constrained rivers dominate, whereas in the Flinders and Fitzroy catchments, anabranching rivers dominate. The dominant river types need benchmarking with adequate numbers of control reaches so that channel changes induced by human and natural impacts can be measured by reference to the stability of these controls. Wandering rivers, floodouts and non‐channelized valley floors were rare for the 1:250 000 channel network in northern Australia but need inclusion in national parks.