U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 4
Station ID: 8663618 PUBLICATION DATE: 05/20/2003
Name: MC CLELLANVILLE, JEREMY CREEK
SC
NOAA Chart: 11531 Latitude: 33° 4.7' N ( 33.07830)
USGS Quad: MC CLELLANVILLE Longitude: 79° 27.6' W ( -79.46000)
To reach the tidal bench marks from the intersection of U.S. Highway 17/701 and
State Highway 45 in a community known locally as Moores Corner, proceed SE on
State Highway 45 for 2.4 km (1.5 mi) through Mc Clellanville to the South
Carolina Crab Company dock. The bench marks are near the crab company and on
adjacent municipal grounds. The tide gage and staff were on the SW corner of
the Crab Company dock.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: JC NO 1 1975
DESIGNATION: 866 3618 TIDAL JC 1
MONUMENTATION: Tidal Station disk VM#: 3998
AGENCY: National Ocean Survey (NOS) IDB PID#: DD0963
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID:
LATITUDE: 33° 4.8' N ( 33.08000) LONGITUDE: 79° 27.5' W ( -79.45830)
The primary bench mark is a disk set along the south side of the dirt road
leading from the south end of Pinckney Street to South Carolina Crab Company,
about 69 m (225 ft) east of the crab company, 31 m (101 ft) NNW of the NW corner
of the last house on the south side of the road, 5.79 m (19.0 ft) SE of the
centerline of the dirt road, and 1.65 m (5.4 ft) SW of power pole #88972. The
bench mark is crimped to a copper-clad steel rod driven an unspecified depth 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 4
Station ID: 8663618 PUBLICATION DATE: 05/20/2003
Name: MC CLELLANVILLE, JEREMY CREEK
SC
NOAA Chart: 11531 Latitude: 33° 4.7' N ( 33.07830)
USGS Quad: MC CLELLANVILLE Longitude: 79° 27.6' W ( -79.46000)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: JC NO 3 1975
DESIGNATION: 866 3618 TIDAL JC 3
MONUMENTATION: Tidal Station disk VM#: 4000
AGENCY: National Ocean Survey (NOS) IDB PID#: DD0961
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID:
LATITUDE: 33° 4.9' N ( 33.08170) LONGITUDE: 79° 27.5' W ( -79.45830)
The bench mark is a disk set near the SW corner of the municipal offices parking
lot, about 41 m (135 ft) north of bench mark JC NO 2 1975, 7.41 m (24.3 ft) SE
of the town flagpole, 4.27 m (14.0 ft) NE of the NW corner post of a chain link
fence, and 0.91 m (3.0 ft) NNW of the fence. The bench mark is crimped to a
copper-clad steel rod driven an unspecified depth to refusal, and encased in a
4-inch PVC pipe and concrete kickblock.
BENCH MARK STAMPING: JC NO 5 1975
DESIGNATION: 866 3618 TIDAL JC 5
MONUMENTATION: Tidal Station disk VM#: 4002
AGENCY: National Ocean Survey (NOS) IDB PID#: DD0959
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID:
LATITUDE: 33° 4.9' N ( 33.08170) LONGITUDE: 79° 27.5' W ( -79.45830)
The bench mark is a disk set near Mc Clellanville Lookout Tower, about 36.58 m
(120 ft) north of bench mark JC NO 4 1975, 10.06 m (33 ft) NW of a 0.01 m (0.3
ft) diameter pipe supporting a basketball backboard, 4.72 m (15.5 ft) ESE of a
0.40 m (1.3 ft) diameter pine tree, 1.19 m (3.9 ft) SSW of the SW corner post
of the fence around the tower, and 0.61 m (2 ft) east of a metal witness post.
The bench mark is crimped to a copper-clad steel rod driven an unspecified depth
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 3 of 4
Station ID: 8663618 PUBLICATION DATE: 05/20/2003
Name: MC CLELLANVILLE, JEREMY CREEK
SC
NOAA Chart: 11531 Latitude: 33° 4.7' N ( 33.07830)
USGS Quad: MC CLELLANVILLE Longitude: 79° 27.6' W ( -79.46000)
T I D A L D A T U M S
Tidal datums at MC CLELLANVILLE, JEREMY CREEK based on:
LENGTH OF SERIES: 3 MONTHS
TIME PERIOD: April 1976 - June 1976
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:
MEAN HIGHER HIGH WATER MHHW = 1.650
MEAN HIGH WATER MHW = 1.532
North American Vertical Datum NAVD88 = 0.886
MEAN SEA LEVEL MSL = 0.792
MEAN TIDE LEVEL MTL = 0.792
MEAN LOW WATER MLW = 0.052
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
JC NO 1 1975 3.066 1.534
JC NO 3 1975 2.443 0.911
JC NO 5 1975 2.522 0.990
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 4
Station ID: 8663618 PUBLICATION DATE: 05/20/2003
Name: MC CLELLANVILLE, JEREMY CREEK
SC
NOAA Chart: 11531 Latitude: 33° 4.7' N ( 33.07830)
USGS Quad: MC CLELLANVILLE Longitude: 79° 27.6' W ( -79.46000)
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.