What causes salinity regimes in coastal waters to change?
• The salinity distribution within coastal waterways reflects the relative influx of fresh water supplied by rivers, and marine water supplied by exchange with the ocean (Figure 1). Salinity levels fluctuate with the penetration of tidal flows, and with mixing of fresh water and marine water by wind and currents. Freshwater discharges to Australia’s coastal waterways are mainly episodic [3], and are primarily controlled by conditions in the catchment including rainfall patterns, vegetation type and cover, topography, catchment area, and geology. Climatic factors may vary seasonally and inter-annually (e.g. with El Nino Southern Oscillation events). Entrance size (and seasonal closure in some areas) and sea level dictate marine water exchange, and the extent to which salinity can build up within the coastal waterway due to evaporation during times of low river flow [1,2]. • Decreased freshwater inflows, due to the diversion of rivers and streams into impoundments, lead to the dissipatio
