The Gordon-above-Olga scheme is one of several major hydro-electric developments under investigation in the south-west of Tasmania. The proposed storage area includes a zone of Palaeozoic limestone forming part of the eastern limb of a synclinal structure which provided a potential for the existence of leakage paths capable of threatening the viability of the scheme.
The geology of the area is described and the methods used in assessing the likelihood of existence of subjacent karst are detailed. The conclusion is drawn on several grounds that neither recent nor ancient activity is likely to have markedly affected the limestone through the synclinorium. In consequence the water-tightness of the proposed reservoir is predicted.