A framework for estimating the extent and severity of drought, based on a grazing system in South-eastern Australia

The National Drought Policy of Australia was ratified by the Commonwealth, States and Territories in 1992. However, before it was fully implemented, one of the most severe droughts on record was already establishing itself across Australia. The Commonwealth government, therefore, devised measures to determine which areas had been exposed to exceptional drought so that financial assistance could be directed as effectively as possible. Six criteria were agreed to nationally, namely meteorological, agronomic, and environmental conditions, water supply, net farm income, and the spatial extent of the drought. Assessments during 1994-95 had to account for the wide range of environments and farming systems. Useful data were often at a premium. In this paper we describe some of the ways in which these criteria have been estimated and assessed. Ways in which simulation models can be used to objectively estimate the extent and severity of drought are also demonstrated and discussed.