U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 4
PUBLICATION DATE: 09/04/1984
Station ID: 8674301 SUPERCEDED DATE: 04/21/2003
Name: DAYMARK #135, SOUTH NEWPORT RIVER, SAPELO SOUND
GEORGIA
NOAA Chart: 11510 Latitude: 31° 34.5' N
USGS Quad: SAPELO SOUND Longitude: 81° 11.4' W
To reach the tidal bench marks proceed by boat to Daymark #135 (FL 4 sec 16 ft 5
m) on the south Newport River, 1 mile (1.6 km) north of the junction with Sapelo
Sound. The bench marks are set on the west bank of the marsh bordered by south
Newport River and Brunsen Creek. The tide gage and staff were mounted on
Daymark #135, west of Bench Mark 4301 B 1977.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 4301 A 1977
MONUMENTATION: Survey Disk VM#: 4800
AGENCY: PID:
SETTING CLASSIFICATION: Unspecified Deep Rod
The bench mark is located on the marsh NE of Daymark #135, 108.5 feet (33.1 m)
NNE of Bench Mark 4301 B 1977, 30 feet (9.1 m) east of the shoreline, and 1.5
feet (0.5 m) west of a witness post. The bench mark is crimped to the top of a
rod driven 48 feet (14.6 m) to refusal, encased in a PVC pipe and concrete
kickblock.
BENCH MARK STAMPING: 4301 B 1977
MONUMENTATION: Survey Disk VM#: 4801
AGENCY: PID:
SETTING CLASSIFICATION: Unspecified Deep Rod
The bench mark is located in the marsh east of Daymark #135, 173 feet (52.7 m)
north of Bench Mark 4301 C 1977, 108.5 feet (33.1 m) SSW of Bench mark 4301 A
1977, 38.8 feet (11.8 m) east of the shoreline, and 1.3 feet (0.4 m) west of a
witness post. The bench mark is crimped to the top of a rod driven 56 feet
(17.1 m) to refusal, encased in a PVC pipe and concrete kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 4
PUBLICATION DATE: 09/04/1984
Station ID: 8674301 SUPERCEDED DATE: 04/21/2003
Name: DAYMARK #135, SOUTH NEWPORT RIVER, SAPELO SOUND
GEORGIA
NOAA Chart: 11510 Latitude: 31° 34.5' N
USGS Quad: SAPELO SOUND Longitude: 81° 11.4' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 4301 C 1977
MONUMENTATION: Survey Disk VM#: 4802
AGENCY: PID:
SETTING CLASSIFICATION: Unspecified Deep Rod
The bench mark is located in the marsh SW of Daymark #135, 173 feet (52.7 m)
south of Bench Mark 4301 B 1977, 128.7 feet (39.2 m) north of Bench Mark 4301 D
1977, 30.5 feet (9.3 m) east of the shoreline, and 1.1 feet (0.3 m) west of a
witness post. The bench mark is crimped to the top of a rod driven 56 feet
(17.1 m) to refusal, encased in a PVC pipe and concrete kickblock.
BENCH MARK STAMPING: 4301 D 1977
MONUMENTATION: Survey Disk VM#: 4803
AGENCY: PID:
SETTING CLASSIFICATION: Unspecified Deep Rod
The bench mark is located in the marsh SW of Daymark #135, 138.8 feet (42.3 m)
NNW of Bench Mark 4301 E 1977, 20.9 feet (6.4 m) east of the shoreline, and 1.5
feet (0.5 m) west of a witness post. The bench mark is crimped to the top of a
rod driven 56 feet (17.1 m) to refusal, encased in a PVC pipe and concrete
kickblock.
BENCH MARK STAMPING: 4301 E 1977
MONUMENTATION: Survey Disk VM#: 4804
AGENCY: PID:
SETTING CLASSIFICATION: Unspecified Deep Rod
The bench mark is located in the marsh SSE of Daymark #135, 74 feet (22.5 m)
east of the shoreline, and 2.7 feet (0.8 m) west of a witness post. The bench
mark is crimped to the top of a rod driven 56 feet (17.1 m) to refusal, encased
in a PVC pipe and concrete kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 4
PUBLICATION DATE: 09/04/1984
Station ID: 8674301 SUPERCEDED DATE: 04/21/2003
Name: DAYMARK #135, SOUTH NEWPORT RIVER, SAPELO SOUND
GEORGIA
NOAA Chart: 11510 Latitude: 31° 34.5' N
USGS Quad: SAPELO SOUND Longitude: 81° 11.4' W
T I D A L D A T U M S
Tidal datums at DAYMARK #135, SOUTH NEWPORT RIVER, SAPELO SOUND based on:
LENGTH OF SERIES: 2 MONTHS
TIME PERIOD: APRIL & MAY 1977
TIDAL EPOCH: 1960-1978
CONTROL TIDE STATION: 8720030 FERNANDINA BEACH, FLORIDA
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET:
HIGHEST OBSERVED WATER LEVEL (06/01/1977) = 9.67
MEAN HIGHER HIGH WATER MHHW = 7.66
MEAN HIGH WATER MHW = 7.29
MEAN TIDE LEVEL MTL = 3.76
MEAN LOW WATER MLW = 0.23
MEAN LOWER LOW WATER MLLW = 0.00
LOWEST OBSERVED WATER LEVEL (04/05/1977) = -2.86
Bench Mark Elevation Information In FEET above:
Stamping or Designation MLLW MHW
4301 A 1977 7.87 0.58
4301 B 1977 7.98 0.69
4301 C 1977 8.16 0.87
4301 D 1977 8.10 0.81
4301 E 1977 8.79 1.50
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 4
PUBLICATION DATE: 09/04/1984
Station ID: 8674301 SUPERCEDED DATE: 04/21/2003
Name: DAYMARK #135, SOUTH NEWPORT RIVER, SAPELO SOUND
GEORGIA
NOAA Chart: 11510 Latitude: 31° 34.5' N
USGS Quad: SAPELO SOUND Longitude: 81° 11.4' 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.