U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
PUBLICATION DATE: 05/22/1987
Station ID: 8661734 SUPERCEDED DATE: 04/21/2003
Name: MOUNT PLEASANT PLANTATION, BLACK RIVER
SOUTH CAROLINA
NOAA Chart: Latitude: 33° 29.7' N
USGS Quad: OLIN Longitude: 79° 27.7' W
To reach the tidal bench marks from the intersection of State Highway 41 and
U.S. Highway 521 in Andrews, proceed NNE along State Highway 41 North for 4.6
miles (7.4 km) to State Road S-22-38, turn east onto State Road S-22-38, proceed
3.2 miles (5.1 km) in a northeasterly direction through the entrance of Mt.
Pleasant Plantation, follow the drive for 1.4 miles (2.3 km) to the main house.
The bench marks are along the drive. Check with the Plantation caretaker, Mr.
R. Jones, when entering the property. The tide gage and staff were located on a
wooden dock on the Black River, NE of the main house.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 1734 A 1981
MONUMENTATION: Survey Disk VM#: 3865
AGENCY: PID#: DD2177
SETTING CLASSIFICATION: Galvanized Steel Rod
The bench mark is 100.1 feet (30.5 m) SSE of the SE corner of a one-room brick
pumphouse, 28.4 feet (8.7 m) WNW of the paved road leading to the main house,
20.6 feet (6.3 m) west of a drainage hole with grating, 12.0 feet (3.7 m) ENE of
the center of a parking area adjacent to the paved road leading to the main
house, and 3.6 feet (1.1 m) WSW of a utility pole. The bench mark is 0.1 foot
(0.03 m) below ground level, crimped to a galvanized steel rod driven 18 feet (5
m) to refusal, and encased in a PVC pipe and concrete kickblock.
BENCH MARK STAMPING: HORZ STATION PLEASANT 1981
MONUMENTATION: Survey Disk VM#: 3861
AGENCY: PID#: DD2172
SETTING CLASSIFICATION: Concrete Monument
The bench mark is set flush in a concrete monument, 100.4 feet (30.6 m) west of
Bench Mark RM 1 PLEASANT 1981, 89.5 feet (27.3 m) ESE of Bench Mark RM 2
PLEASANT 1981, 27.3 feet (8.3 m) NNE of the centerline of the dirt road, 18.2
feet (5.5 m) south of the wooden fence of the horse paddock west of the
livestock barn, and at ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
PUBLICATION DATE: 05/22/1987
Station ID: 8661734 SUPERCEDED DATE: 04/21/2003
Name: MOUNT PLEASANT PLANTATION, BLACK RIVER
SOUTH CAROLINA
NOAA Chart: Latitude: 33° 29.7' N
USGS Quad: OLIN Longitude: 79° 27.7' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: RM 1 PLEASANT 1981
MONUMENTATION: Survey Disk VM#: 3862
AGENCY: PID#: DD2173
SETTING CLASSIFICATION: Concrete Monument
The bench mark is set flush in a concrete monument, 62.4 feet (19.0 m) NW of a
utility pole, 57.3 feet (17.5 m) NNE of the centerline of the dirt road, 17.6
feet (5.4 m) SSW of a one-room brick pumphouse door entrance, and at ground
level.
BENCH MARK STAMPING: RM 2 PLEASANT 1981
MONUMENTATION: Survey Disk VM#: 3863
AGENCY: PID#: DD2174
SETTING CLASSIFICATION: Concrete Monument
The bench mark is set flush in a concrete monument, 21.3 feet (6.5 m) NNE of the
centerline of the main dirt road, 11.6 feet (3.5 m) ESE of the centerline of the
lesser-used road perpendicular to the dirt road, 1.3 feet (0.4 m) south of the
southwestern wooden corner post of the horse paddock, 1.2 feet (0.4 m) SSW of a
metal witness post with sign, and at ground level.
BENCH MARK STAMPING: AZ MK PLEASANT 1981
MONUMENTATION: Survey Disk VM#: 3864
AGENCY: PID#: DD2171
SETTING CLASSIFICATION: Concrete Monument
The bench mark is set flush in a concrete monument, 73.4 feet (22.4 m) SW of the
SW corner of a wooden barn, 14.3 feet (4.4 m) SSW of the centerline of the dirt
road, 12.4 feet (3.8 m) WNW of the center of a twin-trunked magnolia tree, 2.6
feet (0.8 m) NNE of a metal witness post with sign, and at ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
PUBLICATION DATE: 05/22/1987
Station ID: 8661734 SUPERCEDED DATE: 04/21/2003
Name: MOUNT PLEASANT PLANTATION, BLACK RIVER
SOUTH CAROLINA
NOAA Chart: Latitude: 33° 29.7' N
USGS Quad: OLIN Longitude: 79° 27.7' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1734 B 1981
MONUMENTATION: Survey Disk VM#: 3866
AGENCY: PID#: DD2176
SETTING CLASSIFICATION: Galvanized Steel Rod
The bench mark is 249.0 feet (75.9 m) north of Bench Mark 1734 A 1981, 56.7 feet
(17.3 m) SE of a 4.0-foot (1.2 m) diameter live oak tree, 24.2 feet (7.4 m) SW
of the centerline of a dirt drive, 18.4 feet (5.6 m) WNW of twin oak trees, and
3.9 feet (1.2 m) NNE of a metal witness post with sign. The bench mark is 0.2
foot (0.1 m) below ground level, crimped to a galvanized steel rod driven 30
feet (9 m) to refusal, and encased in a PVC pipe and concrete kickblock.
BENCH MARK STAMPING: 1734 C 1981
MONUMENTATION: Survey Disk VM#: 3867
AGENCY: PID#: DD2175
SETTING CLASSIFICATION: Galvanized Steel Rod
The bench mark is 57.4 feet (17.5 m) NNE of the centerline of a dirt road, 43.9
feet (13.4 m) WNW of the center of the door on the west end of the stable, 11.0
feet (3.4 m) NNE of a utility pole guy wire anchor, 9.7 feet (3.0 m) SSW of
a metal witness post with sign, and 6.1 feet (1.9 m) WSW of a utility pole. The
bench mark is 0.3 foot (0.1 m) below ground level, crimped to a galvanized steel
rod driven 35 feet (11 m) to refusal, and encased in a PVC pipe and concrete
kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
PUBLICATION DATE: 05/22/1987
Station ID: 8661734 SUPERCEDED DATE: 04/21/2003
Name: MOUNT PLEASANT PLANTATION, BLACK RIVER
SOUTH CAROLINA
NOAA Chart: Latitude: 33° 29.7' N
USGS Quad: OLIN Longitude: 79° 27.7' W
T I D A L D A T U M S
Tidal datums at MOUNT PLEASANT PLANTATION, BLACK RIVER based on:
LENGTH OF SERIES: 12 MONTHS
TIME PERIOD: JANUARY-DECEMBER 1982
TIDAL EPOCH: 1960-1978
CONTROL TIDE STATION: 8662746 SOUTH ISLAND PLANTATION
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET:
HIGHEST OBSERVED WATER LEVEL (02/02/1983) = 3.56
MEAN HIGHER HIGH WATER MHHW = 2.08
MEAN HIGH WATER MHW = 2.02
MEAN TIDE LEVEL MTL = 1.11
MEAN LOW WATER MLW = 0.20
MEAN LOWER LOW WATER MLLW = 0.00
LOWEST OBSERVED WATER LEVEL (12/24/1981) = -2.00
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In FEET above:
Stamping or Designation MLLW MHW
1734 A 1981 23.74 21.72
HORZ STATION PLEASANT 1981 49.48 47.46
RM 1 PLEASANT 1981 49.71 47.69
RM 2 PLEASANT 1981 49.71 47.69
AZ MK PLEASANT 1981 42.86 40.84
1734 B 1981 41.15 39.13
1734 C 1981 39.83 37.81
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
PUBLICATION DATE: 05/22/1987
Station ID: 8661734 SUPERCEDED DATE: 04/21/2003
Name: MOUNT PLEASANT PLANTATION, BLACK RIVER
SOUTH CAROLINA
NOAA Chart: Latitude: 33° 29.7' N
USGS Quad: OLIN Longitude: 79° 27.7' 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.