Some effects of the 1982-83 drought on water quality and macroinvertebrate fauna in the lower La Trobe River, Victoria

Abstract

Following severe and prolonged drought, flows in parts of the lower LaTrobe River reached record lows in February 1983. Consequent lack of dilution for wastewater discharges resulted in marked deterioration of water quality, with dissolved oxygen concentration dropping to 2 g m^-3 and electrical conductivity rising to 115 mS m^-1. Despite these changes there was little alteration in the taxonomic richness or composition of the aquatic macroinvertebrate fauna. Faunal richness in the river downstream from Yallourn was low both before and after the drought, but the causative factors remain obscure.