Water-Level Analysis for Cumberland Sound, Georgia.
ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS
Pagination or Media Count:
Cumberland Sound, Georgia, is a large and complex estuary covering an area of approximately 240 square miles, which is connected to the Atlantic Ocean through a dredged inlet channel called St Marys Entrance. St. Marys Entrance consists of a Federally maintained navigation channel protected by two jetties separating Cumberland Island, Georgia, to the north and Amelia Island, Florida, to the south. The channel through St Marys Entrance is maintained at a 50-ft depth through significant dredging that occurred from 1986-1988 Questions arose as to whether this dredging had raised the water level in Cumberland Sound. The U.S. Army Engineer Waterways Experiment Station commissioned the study that is documented in this report in order to review and interpret the water-level record available from tide stations operated in Cumberland Sound by the National Ocean Service, National Oceanic and Atmospheric Administration. Objectives of this study were to analyze long-term water-level records to determine if recent 1986-1988 dredging along Cumberland Sound and St Marys entrance altered the water level in Cumberland Sound and to quantify the change, if it was found. Conclusions of the study were as follows a A statistical hypothesis test indicated that there was no discernible change in mean tide level mfl after dredging. b For the period 1939-1992, mtl increased in Cumberland Sound at an annual rate of 2,4 mmyear. c The mtl tracked closely among the three tide stations that were monitored. d Tide range in Cumberland Sound has a periodicity of about 19 years, and from 1992 to 1993, the range should cross through its long-term mean value and increase for the next several years. e Mean high water gradually increased from 1939-1992, and this tide datum tracked well in long-term trend and short-term variations for the three tide stations.
- Physical and Dynamic Oceanography