U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 4
PUBLICATION DATE: 06/01/1990
Station ID: 8677832 SUPERCEDED DATE: 04/21/2003
Name: JEKYLL ISLAND MARINA, JEKYLL CREEK
GEORGIA
NOAA Chart: 11504 Latitude: 31° 3.4' N
USGS Quad: JEKYLL ISLAND Longitude: 81° 25.4' W
To reach the tidal bench marks from Brunswick, proceed south on U.S. Highway 17
across the Sidney Lanier Bridge to Jekyll Island Causeway, turn left (east) and
travel across the causeway to Jekyll Island, turn left (north) onto Riverview
Drive and continue to Jekyll Island Marina. The bench marks are near the end of
the pier and in the adjacent seawall at Jekyll Island Marina. The tide gage and
staff were on the pier.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 7832 A 1980
MONUMENTATION: Survey Disk VM#: 4936
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Sea Wall
The bench mark is set flush in the center of the east-west running sea wall
which intersects a north-south sea wall, 128.0 feet (39.0 m) north of the pier,
and 17 feet (5 m) east of the north-south sea wall.
BENCH MARK STAMPING: 7832 B 1980
MONUMENTATION: Survey Disk VM#: 4937
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Foundation
The bench mark is set flush in a 3.5-foot (1.1 m) square concrete water fountain
foundation, immediately adjacent to a sidewalk running north-south from the
marina parking lot (by the bathhouse) to Pier Street, 138.0 feet (42.1 m) south
of Bench Mark 7832 A 1980, 35.0 feet (10.7 m) east of the north-south sea wall,
and 10.0 feet (3.0 m) south of the centerline of Pier Street.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 4
PUBLICATION DATE: 06/01/1990
Station ID: 8677832 SUPERCEDED DATE: 04/21/2003
Name: JEKYLL ISLAND MARINA, JEKYLL CREEK
GEORGIA
NOAA Chart: 11504 Latitude: 31° 3.4' N
USGS Quad: JEKYLL ISLAND Longitude: 81° 25.4' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 7832 C 1980
MONUMENTATION: Survey Disk VM#: 4938
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Steps
The bench mark is set flush in the NE corner of a 3.2-foot (1.0 m) square
concrete step at the entrance door of the womens lavatory at the bathhouse, at
the NW corner of the bathhouse building, 43.0 feet (13.1 m) SE of the end of the
pier, and 11.0 feet (3.4 m) east of the sea wall.
BENCH MARK STAMPING: 7832 D 1980
MONUMENTATION: Survey Disk VM#: 4939
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Sea Wall
The bench mark is set flush in the concrete sea wall, 200 feet (61 m) south of
the south edge of the pier, 157.0 feet (49.7 m) SSW of Bench Mark 7832 C 1980,
and 0.8 foot (0.2 m) east of the west edge of the sea wall.
BENCH MARK STAMPING: NO. 1 49
MONUMENTATION: Survey Disk VM#: 4940
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Sea Wall
The bench mark is set flush in top of a concrete sea wall just north of the end
of the pier, and 127.0 feet (38.7 m) SSW of Bench Mark 7832 A 1980.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 4
PUBLICATION DATE: 06/01/1990
Station ID: 8677832 SUPERCEDED DATE: 04/21/2003
Name: JEKYLL ISLAND MARINA, JEKYLL CREEK
GEORGIA
NOAA Chart: 11504 Latitude: 31° 3.4' N
USGS Quad: JEKYLL ISLAND Longitude: 81° 25.4' W
T I D A L D A T U M S
Tidal datums at JEKYLL ISLAND MARINA, JEKYLL CREEK based on:
LENGTH OF SERIES: 66 HIGH & 65 LOW WAT
TIME PERIOD: MAY 24 - JUNE 26, 1980
TIDAL EPOCH: 1960-1978
CONTROL TIDE STATION: 8670870 FT. PULASKI
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET:
HIGHEST OBSERVED WATER LEVEL (06/12/1980) = 9.41
MEAN HIGHER HIGH WATER MHHW = 7.36
MEAN HIGH WATER MHW = 7.02
MEAN TIDE LEVEL MTL = 3.63
MEAN LOW WATER MLW = 0.23
MEAN LOWER LOW WATER MLLW = 0.00
LOWEST OBSERVED WATER LEVEL (06/08/1980) = -1.35
Bench Mark Elevation Information In FEET above:
Stamping or Designation MLLW MHW
7832 A 1980 13.08 6.06
7832 B 1980 13.92 6.90
7832 C 1980 13.72 6.70
7832 D 1980 13.07 6.05
NO. 1 49 13.07 6.05
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 4
PUBLICATION DATE: 06/01/1990
Station ID: 8677832 SUPERCEDED DATE: 04/21/2003
Name: JEKYLL ISLAND MARINA, JEKYLL CREEK
GEORGIA
NOAA Chart: 11504 Latitude: 31° 3.4' N
USGS Quad: JEKYLL ISLAND Longitude: 81° 25.4' W
D E F I N I T I O N S
Mean Sea Level (MSL) is a tidal datum determined over a 19-year National Tidal
Datum Epoch. It pertains to local mean sea level and should not be confused
with the fixed datums of North American Vertical Datum of 1988 (NAVD88).
NAVD88 is a fixed datum derived from a simultaneous, least squares, minimum
constraint adjustment of Canadian/Mexican/United States leveling observations.
Local mean sea level observed at Father Point/Rimouski, Canada was held fixed as
the single initial constraint. NAVD88 replaces NGVD29 as the national
standard geodetic reference for heights. Bench mark elevations relative to
NAVD88 are available from NGS through the World Wide Web at
National Geodetic Survey.
NGVD29 is a fixed datum adopted as a national standard geodetic reference for
heights but is now considered superseded. NGVD29 is sometimes referred to as
Sea Level Datum of 1929 or as Mean Sea Level on some early issues of Geological
Survey Topographic Quads. NGVD29 was originally derived from a general
adjustment of the first-order leveling networks of the U.S. and Canada after
holding mean sea level observed at 26 long term tide stations as fixed.
Numerous local and wide-spread adjustments have been made since establishment in
1929. Bench mark elevations relative to NGVD29 are available from the National
Geodetic Survey (NGS) data base via the World Wide Web at
National Geodetic Survey.
NAVD88 and NGVD29 are fixed geodetic datums whose elevation relationships to
local MSL and other tidal datums may not be consistent from one location to
another.
The Vertical Mark Number (VM#) and PID# shown on the bench mark sheet are unique
identifiers for bench marks in the tidal and geodetic databases, respectively.
Each bench mark in either database has a single, unique VM# and/or PID# assigned.
Where both VM# and PID# are indicated, both tidal and geodetic elevations are
available for the bench mark listed.
The NAVD88 elevation is shown on the Elevations of Tidal Datums Table Referred
to MLLW only when two or more of the bench marks listed have NAVD88 elevations.
The NAVD88 elevation relationship shown in the table is derived from an average
of several bench mark elevations relative to tide station datum. As a result of
this averaging, NAVD88 bench mark elevations computed indirectly from the tidal
datums elevation table may differ slightly from NAVD88 elevations listed for
each bench mark in the NGS database.