Salinization of the Glenelg River in Southwest Victoria, Australia

Southwest Victoria, Australia, has many lakes and rivers, most of which cannot be used for agricultural or domestic purposes because of their high salt content. The Glenelg River, located 300 km west ofMelboume, is the largest river in southwest Victoria and an important ecological and agricultural water resource. Although local precipitation i s more than 600 mm per year, the Glenelg River's salt content exceeds l/l O that of sea water with electrical conductivity (EC) values of several thousand J.LS/cm. In these reaches it cannot be used as drinking or irrigation water. Historically, river salinization has been attributed to (l) evaporation and concentration during reservoir storage, irrigation, and subsequent reuse; (2) displacement o f shallow saline groundwater during irrigation; (3) erosion and dissolution of natural deposits; andlor (4) inflow of deep saline and/or geothermal groundwater (MooRE et al. 2008). Hydrogen and oxygen stable isotopes and chloride concentration have proved useful for determining salt sources (DRUHAN et al. 2008). The purpose of our study was to determine the origin o f the sai t and how it concentrates in the Glenelg River using oxygen and hydrogen stable isotopes and chloride content.