U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 4
Station ID: 8665167 PUBLICATION DATE: 10/30/2003
Name: HAMLIN SOUND
SC
NOAA Chart: 11521 Latitude: 32° 49.6' N ( 32.82670)
USGS Quad: FORT MOULTRIE Longitude: 79° 47.2' W ( -79.78670)
To reach the tidal bench marks from the east end of the U.S. Highway 17 bridge
over Cooper River in Mt. Pleasant, proceed north on U.S. Highway 17 for 12.1 km
(7.5 mi) to Hamlin Drive (S-10-504), then turn right and proceed SE on Hamlin
Drive for 1.8 km (1.1 mi) to the entrance to Old Hamlin Farms, then turn right
onto the dirt driveway and proceed 0.3 km (0.2 mi) to the O.D. Hamlin residence.
The bench marks are along the dirt driveway leading to the residence. The tide
gage and staff were on the Hamlin private pier.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 5167 A 1978
DESIGNATION: 866 5167 A TIDAL
MONUMENTATION: Tidal Station disk VM#: 4142
AGENCY: National Ocean Survey (NOS) IDB PID#: CJ0283
SETTING CLASSIFICATION: Galvanized steel rod OPUS PID#: CJ0283
LATITUDE: 32° 49.6' N ( 32.82670) LONGITUDE: 79° 47.2' W ( -79.78670)
The primary bench mark is a disk located 13.26 m (43.5 ft) NW of a palmetto
piling at the land end of another small dock located at the NE side of the
island at the end of the causeway leading to the pier, 9.27 m (30.4 ft) north of
the land end of a small dock on the west side of the small island, 5.79 m (19.0
ft) WSW of the centerline of the road on the causeway, and 0.27 m (0.9 ft) NE of
a metal witness post with sign. The bench mark is set 6 cm (0.2 ft) below
ground level, crimped to the top of a galvanized steel rod driven 11.3 m (37 ft)
to refusal, and encased in a 5-inch PVC pipe and concrete kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 4
Station ID: 8665167 PUBLICATION DATE: 10/30/2003
Name: HAMLIN SOUND
SC
NOAA Chart: 11521 Latitude: 32° 49.6' N ( 32.82670)
USGS Quad: FORT MOULTRIE Longitude: 79° 47.2' W ( -79.78670)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 5167 G 1982
DESIGNATION: 866 5167 G TIDAL
MONUMENTATION: Tidal Station disk VM#: 4145
AGENCY: National Ocean Survey (NOS) IDB PID#: CJ1473
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 32° 49.8' N ( 32.83000) LONGITUDE: 79° 47.5' W ( -79.79170)
The bench mark is a disk located 30.18 m (99.0 ft) south of the SE corner of a
0.61 m (2.0 ft) well, 20.88 m (68.5 ft) SE of the SE corner of the brick steps
(the ruins), 11.37 m (37.3 ft) NW of a live oak tree beside the road, 7.32 m
(24.0 ft) SW of the centerline of the dirt road leading to the house trailer and
pier, and 0.46 m (1.5 ft) SSW of a metal witness post with sign. The bench mark
is set 6 cm (0.2 ft) below ground level, crimped to the top of a stainless steel
rod driven 13.4 m (44 ft) to refusal, and encased in a 5-inch PVC pipe and
concrete kickblock.
BENCH MARK STAMPING: 5167 H 1982
DESIGNATION: 866 5167 H TIDAL
MONUMENTATION: Tidal Station disk VM#: 4146
AGENCY: National Ocean Survey (NOS) IDB PID#: CJ1474
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 32° 49.8' N ( 32.83000) LONGITUDE: 79° 47.4' W ( -79.79000)
The bench mark is a disk located 32.31 m (106.0 ft) NE of the centerline of the
dirt road, 8.53 m (28.0 ft) ENE of a 0.70 m (2.3 ft) diameter pine tree, 2.13 m
(7.0 ft) SW of the ball housing of the trailer tongue of the mobile home, and
0.82 m (2.7 ft) SSE of the most SE pole of the awnings of the mobile home. The
bench mark is set 9 cm (0.3 ft) below ground level, crimped to the top of a
stainless steel rod driven 14.6 m (48 ft) to refusal, and encased in a 5-inch
PVC pipe and concrete kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 4
Station ID: 8665167 PUBLICATION DATE: 10/30/2003
Name: HAMLIN SOUND
SC
NOAA Chart: 11521 Latitude: 32° 49.6' N ( 32.82670)
USGS Quad: FORT MOULTRIE Longitude: 79° 47.2' W ( -79.78670)
T I D A L D A T U M S
Tidal datums at HAMLIN SOUND based on:
LENGTH OF SERIES: 1 YEAR
TIME PERIOD: April 1978 - March 1979
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8665530 CHARLESTON, COOPER RIVER ENTRANCE
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
HIGHEST OBSERVED WATER LEVEL (07/19/1978) = 2.325
MEAN HIGHER HIGH WATER MHHW = 1.755
MEAN HIGH WATER MHW = 1.638
North American Vertical Datum NAVD88 = 0.974
MEAN SEA LEVEL MSL = 0.885
MEAN TIDE LEVEL MTL = 0.847
MEAN LOW WATER MLW = 0.057
MEAN LOWER LOW WATER MLLW = 0.000
LOWEST OBSERVED WATER LEVEL (01/24/1979) = -0.832
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
5167 A 1978 2.559 0.921
5167 G 1982 2.749 1.111
5167 H 1982 2.488 0.850
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 4
Station ID: 8665167 PUBLICATION DATE: 10/30/2003
Name: HAMLIN SOUND
SC
NOAA Chart: 11521 Latitude: 32° 49.6' N ( 32.82670)
USGS Quad: FORT MOULTRIE Longitude: 79° 47.2' W ( -79.78670)
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.