The geomorphology and hydrology of Saline Lakes of the Middle Paroo, Arid-zone Australia

Sixteen subsaline (0.5 – 3 gL⁻¹) and saline lakes (> 3 gL⁻¹) of the Paroo have been studied for periods of up to 18 years. Many were formed by drainage routes being blocked by dunes, some lie in dune swales, some lie at the edge of the Paroo floodplain where alluvial sediments are thinner, and Lake Wyara lies in a depression on a fault line. All developed further by deflation and owe their form to wind-induced currents and wave action shaping shorelines. Most saline lakes have lunette dunes on the eastern shore, and many larger ones have migrated westwards. Lakes of low salinity have sandy beaches and no, or poorly developed, lunettes. Lakes with N-S axes have the southeastern corner cut off by spits generated by currents induced by northwesterley winds. A few lakes are filling with sediment derived from the overgrazing of catchments associated with European settlement. Larger lakes with inflowing streams fill in El Niño years, then dry over the next few years. Smaller lakes without surface inflows may fill a few times in wet years but dry quickly. Most lakes remain dry in La Nina years. Salinity regimes fluctuate widely and, while instantaneous faunal lists may be depauperate, cumulative species lists can be long. However, lakes which normally are fresh, but become saline in their final stage of drying, develop only a limited saline lake fauna.