Georgia Coast

Georgia's barrier-island chain — the Golden Isles and Sea Islands — sits behind a wide, gently shoaling continental shelf that amplifies the tidal wave before it reaches the shore. The result is one of the largest mean tidal ranges on the US Atlantic seaboard: spring tides of 2.7 metres and mean ranges of 2.0 to 2.1 metres at Tybee Island and St. Simons Island. At Savannah, the semi-enclosed Savannah River estuary pushes mean springs toward 2.7 metres and generates tidal river currents of 1.5 to 2.5 knots, making it one of the most significant tidal port approaches on the East Coast. The Georgia coast is defined by its salt marshes. Behind every barrier island lies a labyrinth of tidal creeks, cordgrass flats (Spartina alterniflora), and shallow estuarine sounds. At low water, the mudflat and marsh edge extends hundreds of metres; at high water, the marsh is navigable by shallow-draft boat and kayak. This twice-daily flooding and draining is the engine of the estuary's productivity — the Georgia coastal marshes generate more organic matter per unit area than almost any other North American ecosystem, underpinning fisheries from Georgia to the Carolinas. NOAA CO-OPS maintains active tide gauge stations at Savannah (Fort Pulaski, station 8670870), Tybee Island (station 8670118), and Brunswick (station 8679511), giving the Georgia coast reliable harmonic tide predictions. Tidal data from this page augments those official sources with model-derived forecasts; for navigation on the Savannah River or the Intracoastal Waterway, NOAA CO-OPS and chart 11512 are the authoritative references.