Salinity Response of the Satilla River Estuary to Seasonal Changes in Freshwater Discharge
Jack Blanton (Skidaway
Inst of Oceanography, Savannah, GA), Merryl
Alber and Joan Sheldon (Dept of Marine Sciences, Univ of Georgia, Athens,
Proceedings of the 2001 Georgia Water Resources Conference, Athens, GA (K.J.
Hatcher, editor). pp. 619-622.
full paper can be viewed
This paper describes the salinity regime in the Satilla River Estuary during
two intensive field campaigns in 1999 (20 Jan - 20 Mar and 9 Sept - 19 Oct).
Over the course of these observations, 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.
and its habitats experienced large changes in the salinity regime over a
period of a few months. The salinities observed during the surveys
shifted significantly, with the approximate location of 15 PSU varying from
approximately 10 km from the mouth during high discharge to further than
35 km during low flow.
A single rain
event in late January 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. However, salinities increased
even further as the drought continued, and those observed in July 2000 were
near record levels.
- The salinity
regime of the estuary was extremely responsive to changes in discharge: Discharge
increased sharply at the beginning of the rain event in late Januray, and
the estuary flushed out much of its salt within about 20 d. After the rain,
however, discharge decreased gradually (probably as the result of freshwater
storage in the watershed), and it took 70 d to return to the salinity levels
observed in January.