The Australian River Assessment Scheme (AUSRIVAS) is a series of procedures and associated software for the rapid assessment of river conditions or 'health' using macroinvertebrate communities. AUSRIVAS includes a set of predictive computer models relevant to particular Australian States and Territories, seasons (spring, autumn or spring and autumn combined) and habitats for river macroinvertebrates (eg. riffles and pool edges).The models attempt to predict the macroinvertebrate families in a specified subsample from a standard kick or sweep net sample, assuming natural or near-natural conditions at the sampling site. The predictions are based on physical, chemical and vegetative features of the site. The predicted fauna can then be compared with the fauna actually observed to infer departures of the macroinvertebrate community from its natural state.