U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 8671314 PUBLICATION DATE: 12/19/2018
Name: HALFMOON REEF, HALFMOON RIVER
GA
NOAA Chart: 11512 Latitude: 31° 57.8' N ( 31.96330)
USGS Quad: WASSAW SOUND Longitude: 80° 56.6' W ( -80.94330)
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 1314 A 1994
DESIGNATION: 867 1314 A
MONUMENTATION: Bench Mark disk VM#: 15753
AGENCY: National Ocean Service (NOS) IDB PID:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 31° 57.8' N ( 31.96330) LONGITUDE: 80° 56.6' W ( -80.94330)
The bench mark is a disk located on the beach to the north of the Half Moon Reef
Fish Haven, 370.33 m (1215.0 ft) NW of the NE most pile in the fish haven,
185.32 m (608.0 ft) north of the NW most pile, and 0.34 m (1.1 ft) SSW of a
steel reference rod driven into the ground. The bench mark is set at ground
level, crimped to the top of a stainless steel rod, driven 18.29 m (60.0 ft)
into the ground and encased in a 6-inch PVC the outside of which is protected by
concrete.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 8671314 PUBLICATION DATE: 12/19/2018
Name: HALFMOON REEF, HALFMOON RIVER
GA
NOAA Chart: 11512 Latitude: 31° 57.8' N ( 31.96330)
USGS Quad: WASSAW SOUND Longitude: 80° 56.6' W ( -80.94330)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1314 B 1994
DESIGNATION: 867 1314 B
MONUMENTATION: Bench Mark disk VM#: 15754
AGENCY: National Ocean Service (NOS) IDB PID:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 31° 57.8' N ( 31.96330) LONGITUDE: 80° 56.6' W ( -80.94330)
The bench mark is a disk located on the beach to the north of the Half Moon Reef
Fish Haven, 148.13 m (486.0 ft) NE of the NW most pile in the fish haven, 32 m
(105 ft) west of a 1/2-inch SHC 40 PVC pipe driven into the ground, and 0.30 m
(1 ft) south of a steel reference rod driven into the ground. The bench mark is
set at ground level, crimped to the top of a stainless steel rod, driven 18.29 m
(60.0 ft) into the ground and encased in a 6-inch PVC the outside of which is
protected by concrete.
BENCH MARK STAMPING: 1314 C 1994
DESIGNATION: 867 1314 C
MONUMENTATION: Bench Mark disk VM#: 15755
AGENCY: National Ocean Service (NOS) IDB PID:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 31° 57.8' N ( 31.96330) LONGITUDE: 80° 56.6' W ( -80.94330)
The bench mark is a disk located on the beach to the north of the Half Moon Reef
Fish Haven, 268.83 m (882.0 ft) WSW of a dead tree, 259 m (850 ft) NE of the NE
most pile, and 15.91 m (52.2 ft) NNE of a 1/2-inch SHC 40 PVC pipe driven into
the ground. The bench mark is set at ground level, crimped to the top of a
stainless steel rod, driven 18.29 m (60.0 ft) into the ground and encased in a
6-inch PVC the outside of which is protected by concrete.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 8671314 PUBLICATION DATE: 12/19/2018
Name: HALFMOON REEF, HALFMOON RIVER
GA
NOAA Chart: 11512 Latitude: 31° 57.8' N ( 31.96330)
USGS Quad: WASSAW SOUND Longitude: 80° 56.6' W ( -80.94330)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1314 D 1994
DESIGNATION: 867 1314 D
MONUMENTATION: Bench Mark disk VM#: 15756
AGENCY: National Ocean Service (NOS) IDB PID:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 31° 57.8' N ( 31.96330) LONGITUDE: 80° 56.6' W ( -80.94330)
The bench mark is a disk located on the beach to the north of the Half Moon Reef
Fish Haven, 8.53 m (28.0 ft) SE of a dead tree, 8.32 m (27.3 ft) north of a
cedar tree, and 0.30 m (1 ft) SW of a steel reference rod driven into the
ground. The bench mark is set at ground level, crimped to the top of a
stainless steel rod, driven 18.29 m (60.0 ft) into the ground and encased in a
6-inch PVC the outside of which is protected by concrete.
BENCH MARK STAMPING: 1314 E 1994
DESIGNATION: 867 1314 E
MONUMENTATION: Bench Mark disk VM#: 15757
AGENCY: National Ocean Service (NOS) IDB PID:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 31° 57.8' N ( 31.96330) LONGITUDE: 80° 56.6' W ( -80.94330)
The bench mark is a disk located on the beach to the north of the Half Moon Reef
Fish Haven, 51.5 m (169.0 ft) SE of a dead tree, 5.39 m (17.7 ft) north of a
cedar tree, and 0.37 m (1.2 ft) south of a steel rod driven into te ground. The
bench mark is set at ground level, crimped to the top of a stainless steel rod,
driven 18.29 m (60.0 ft) into the ground and encased in a 6-inch PVC the outside
of which is protected by concrete.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 8671314 PUBLICATION DATE: 12/19/2018
Name: HALFMOON REEF, HALFMOON RIVER
GA
NOAA Chart: 11512 Latitude: 31° 57.8' N ( 31.96330)
USGS Quad: WASSAW SOUND Longitude: 80° 56.6' W ( -80.94330)
T I D A L D A T U M S
Tidal datums at HALFMOON REEF, HALFMOON RIVER based on:
LENGTH OF SERIES: 30 DAYS
TIME PERIOD: Oct 6 1994 - Nov 4 1994
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8670870 FORT PULASKI, SAVANNAH RIVER
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 2.319
MEAN HIGH WATER MHW = 2.197
MEAN SEA LEVEL MSL = 1.158
MEAN TIDE LEVEL MTL = 1.132
MEAN LOW WATER MLW = 0.068
MEAN LOWER LOW WATER MLLW = 0.000
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
1314 A 1994 2.794 0.597
1314 B 1994 2.587 0.390
1314 C 1994 2.515 0.318
1314 D 1994 2.517 0.320
1314 E 1994 2.693 0.496
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 8671314 PUBLICATION DATE: 12/19/2018
Name: HALFMOON REEF, HALFMOON RIVER
GA
NOAA Chart: 11512 Latitude: 31° 57.8' N ( 31.96330)
USGS Quad: WASSAW SOUND Longitude: 80° 56.6' W ( -80.94330)
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 NGS's Integrated Data Base (IDB PID)
provides geodetic datum based on traditionally leveled and bluebooked ties to
the National Spatial Reference System(NSRS) https://www.ngs.noaa.gov/datasheets/.
The NGS Online Positioning User Service (OPUS PID) provides geodetic datum based
on GPS position & tie it to the NSRS https://www.ngs.noaa.gov/OPUS/.
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.