Limnology of four saline lakes in western Victoria, Australia: I. Physico-chemical parameters

Major physico-chemical parameters of four saline lakes (Lake Colac, Modewarre, Bolac and Tooliorook), in the volcanic plains of western Victoria (Australia), recorded bi-monthly between November 1999–September 2001 are described. Lakes are permanent, large (surface area range 3.5–29.6 km²) and shallow (mean depth range 1.5–3.9 m). Physico-chemical parameters revealed that lakes were homogenous with few differences between sites within lakes. Of the four lakes, Lake Modewarre had the highest salinity of 8 ppt with weak seasonal fluctuations in salinity in all the lakes. All the lakes were turbid (turbidity range 30–659 NTU), with low light penetration (suspended solids range 23–465 mg l⁻¹) and low Secchi depth (Secchi depth range 7.7–89 cm). pH of the lakes varied between 8.2–9.3 with low seasonal variations, indicating well buffered waters. Based on nutrient status, lakes were classified as eutrophic to highly eutrophic with higher nutrient concentrations. Nitrogen was limiting in one lake (Lake Colac) and phosphorus in the other three lakes. Meteorological events probably influence the physico-chemical parameters of these lakes strongly.