Published Bench Mark Sheet for 8663461 INTRACOASTAL WATERWAY, CASINO CREEK SOUTH CAROLINA
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
PUBLICATION DATE: 06/28/1989
Station ID: 8663461 SUPERCEDED DATE: 04/21/2003
Name: INTRACOASTAL WATERWAY, CASINO CREEK
SOUTH CAROLINA
NOAA Chart: 11531 Latitude: 33° 6.5' N
USGS Quad: McCLELLANVILLE Longitude: 79° 23.6' W
To reach the tidal bench marks from the boat landing in McClellanville, proceed
by boat from Jeremy Creek to the Intracoastal Waterway at day marker #35, then
go NE on the Intracoastal Waterway for about 4.5 statute miles (7.2 km) to day
marker #29. The tidal bench marks are on the NE end of the island, at the
junction of Casino Creek and the Intracoastal Waterway at day marker #29. The
tide gage and staff were on day marker #29.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 3461 A 1977
MONUMENTATION: Survey Disk VM#: 3982
AGENCY: PID:
SETTING CLASSIFICATION: Copper-clad Steel Rod
The bench mark is 88.5 feet (27.0 m) NE of Bench mark 3461 G 1982, 62.0 feet
(18.9 m) east of Bench Mark 3461 C 1977, 31.4 feet (9.6 m) NNE of a 2-foot (1
m) diameter pine tree, and 1.6 feet (0.5 m) NW of a witness post with sign. The
bench mark is at grade level, crimped to a copper-clad steel rod driven 22 feet
(7 m) to refusal, and encased in a 4-inch PVC pipe and concrete kickblock.
BENCH MARK STAMPING: 3461 C 1977
MONUMENTATION: Survey Disk VM#: 3983
AGENCY: PID:
SETTING CLASSIFICATION: Copper-clad Steel Rod
The bench mark is 63.1 feet (19.2 m) NNW of Bench Mark 3461 G 1982, 20.7 feet
(6.3 m) north of a 2.0-foot (0.6 m) diameter pine tree, 17.1 feet (5.2 m) south
of a 0.5-foot (0.2 m) diameter cedar tree, and 1.6 feet (5 m) NNE of a witness
post with sign. The bench mark is at grade level, crimped to a copper-clad
steel rod driven 16 feet (5 m) to refusal, and encased in a 4-inch PVC pipe and
concrete kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
PUBLICATION DATE: 06/28/1989
Station ID: 8663461 SUPERCEDED DATE: 04/21/2003
Name: INTRACOASTAL WATERWAY, CASINO CREEK
SOUTH CAROLINA
NOAA Chart: 11531 Latitude: 33° 6.5' N
USGS Quad: McCLELLANVILLE Longitude: 79° 23.6' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 3461 E 1977
MONUMENTATION: Survey Disk VM#: 3984
AGENCY: PID:
SETTING CLASSIFICATION: Copper-clad Steel Rod
The bench mark is 43.6 feet (13.3 m) west of a multibase cluster of pine trees,
38.1 feet (11.6 m) south of a 1.5-foot (0.5 m) diameter pine tree, 29.7 feet
(9.1 m) east of a 2.0-foot (0.6 m) diameter multibase cluster of cedar trees,
and 1.1 feet (0.3 m) north of a witness post with sign. The bench mark is at
grade level, crimped to a copper-clad steel rod driven 16 feet (5 m) to refusal,
and encased in a 4-inch PVC pipe and concrete kickblock.
BENCH MARK STAMPING: 3461 F 1982
MONUMENTATION: Survey Disk VM#: 3985
AGENCY: PID:
SETTING CLASSIFICATION: Stainless Steel Rod
The bench mark is 70.8 feet (21.6 m) SE of Bench Mark 3461 C 1977, 42.4 feet
(12.9 m) east of Bench Mark 3461 G 1982, 35.0 feet (10.7 m) south of a 2.0- foot
(0.6 m) diameter pine tree, 19.5 feet (5.9 m) east of a 1.3-foot (0.4 m)
diameter pine tree, and 1.3 feet (0.4 m) NW of a witness post with sign. The
bench mark is at grade level, crimped to a stainless steel rod driven 32 feet
(10 m) 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 5
PUBLICATION DATE: 06/28/1989
Station ID: 8663461 SUPERCEDED DATE: 04/21/2003
Name: INTRACOASTAL WATERWAY, CASINO CREEK
SOUTH CAROLINA
NOAA Chart: 11531 Latitude: 33° 6.5' N
USGS Quad: McCLELLANVILLE Longitude: 79° 23.6' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 3461 G 1982
MONUMENTATION: Survey Disk VM#: 3986
AGENCY: PID:
SETTING CLASSIFICATION: Stainless Steel Rod
The bench mark is 46.0 feet (14.0 m) NNE of Bench Mark 3461 E 1977, 27.0 feet
(8.2 m) NW of a multibase cluster of pine trees, 21.5 feet (6.6 m) east of a
1.5-foot (0.5 m) diameter pine tree, 4.2 feet (1.3 m) WSW of a 1.3-foot (0.4
m) diameter pine tree, and 1.0 foot (0.3 m) north of a witness post with sign.
The bench mark is at grade level, crimped to a stainless steel rod driven 32
feet (10 m) 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 4 of 5
PUBLICATION DATE: 06/28/1989
Station ID: 8663461 SUPERCEDED DATE: 04/21/2003
Name: INTRACOASTAL WATERWAY, CASINO CREEK
SOUTH CAROLINA
NOAA Chart: 11531 Latitude: 33° 6.5' N
USGS Quad: McCLELLANVILLE Longitude: 79° 23.6' W
T I D A L D A T U M S
Tidal datums at INTRACOASTAL WATERWAY, CASINO CREEK based on:
LENGTH OF SERIES: 2 MONTHS
TIME PERIOD: MAY - JUNE 1977
TIDAL EPOCH: 1960-1978
CONTROL TIDE STATION: 8665530 CHARLESTON
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET:
HIGHEST OBSERVED WATER LEVEL (06/01/1977) = 7.90
MEAN HIGHER HIGH WATER (MHHW) = 5.06
MEAN HIGH WATER (MHW) = 4.74
MEAN TIDE LEVEL (MTL) = 2.46
MEAN LOW WATER (MLW) = 0.18
MEAN LOWER LOW WATER (MLLW) = 0.00
LOWEST OBSERVED WATER LEVEL (07/02/1977) = -0.90
National Geodetic Vertical Datum (NGVD 29)
Bench Mark Elevation Information In FEET above:
Stamping or Designation MLLW MHW
3461 A 1977 5.97 1.23
3461 C 1977 8.22 3.48
3461 E 1977 7.34 2.60
3461 F 1982 7.51 2.77
3461 G 1982 9.54 4.80
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
PUBLICATION DATE: 06/28/1989
Station ID: 8663461 SUPERCEDED DATE: 04/21/2003
Name: INTRACOASTAL WATERWAY, CASINO CREEK
SOUTH CAROLINA
NOAA Chart: 11531 Latitude: 33° 6.5' N
USGS Quad: McCLELLANVILLE Longitude: 79° 23.6' 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 (NAVD 88).
NGVD 29 is a fixed datum adopted as a national standard geodetic reference for
heights but is now considered superseded. NGVD 29 is sometimes referred to as
Sea Level Datum of 1929 or as Mean Sea Level on some early issues of Geological
Survey Topographic Quads. NGVD 29 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 NGVD 29 are available from the National
Geodetic Survey (NGS) data base via the World Wide Web at
National Geodetic Survey.
NAVD 88 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. NAVD 88 replaces NGVD 29 as the national
standard geodetic reference for heights. Bench mark elevations relative to
NAVD 88 are available from NGS through the World Wide Web at
National Geodetic Survey.
NGVD 29 and NAVD 88 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 NAVD 88 elevation is shown on the Elevations of Tidal Datums Table Referred
to MLLW only when two or more of the bench marks listed have NAVD 88 elevations.
The NAVD 88 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, NAVD 88 bench mark elevations computed indirectly from the tidal
datums elevation table may differ slightly from NAVD 88 elevations listed for
each bench mark in the NGS database.
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