Salinity Response of the Satilla River to Seasonal Changes in Freshwater Discharge (Poster)
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Georgia's vast brackish water landscape is maintained, to a large extent, by the hydrostatic pressure of freshwater discharges which keep the sea out of these areas. The salinity regime throughout this landscape responds to fluctuations in discharge. We describe the salinity regime in the Satilla River Estuary based on two intensive field campaigns in 1999 (20 Jan - 20 Mar and 9 Sept - 19 Oct). River discharge varied from almost 150 m³s⁻¹ in February (twice the average) due to a single rain event in late January, to below 10 m³s⁻¹ in May and June, after which it remained relatively low. The single discharge event resulted in large decreases in salinity throughout the estuary that lasted for about one week. (Salinity in Crows Harbor Reach was between 12-14 practical salinity units (PSU) on 20 Jan but fell to less than 2 PSU by 5 Feb) After early February, salinity slowly increased and had returned to near January levels by mid-April. Thus, during the ramp-up of river discharge in late January, the estuary flushed out much of its salt within about 20 days, and it took more than 2 months (70 days) to return to the salinity levels observed in January. The events analyzed here are described within the context of a series of salinity surveys over the course of 1999 and 2000, which should enable managers to gain insight into the interactions between river discharge, salinity structure, and flushing times in this system.