Relating baseflow to catchment properties in south-eastern Australia

This paper examines the influence of a set of geology-vegetation groups and a number of dimensionless catchment properties, including topographic and climatic indices, on the baseflow index for 114 catchments in Victoria, Australia, with areas ranging from 0.05 to 192 km(2). There are 12 geology-vegetation groups, based on the geology and indigenous vegetation community of the catchment. They constitute the most important factor determining the value of baseflow index. The groups are considered as surrogates that represent climatic history, the capacity for recharge, and the transmissivity of the bedrock and soils. No trends are found in plots of baseflow index against any dimensionless topographic parameters within the geology-vegetation groups. Examination of annual trends in a catchment that was clearfelled in 1972 shows no evidence that baseflow index is affected by forest growth stage. There appears to be no effect of catchment size on baseflow index for catchment areas up to 100 km(2). The evidence is inconclusive as to a size effect outside this range. (C) 1998 Elsevier Science B.V.