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National Ocean Service
Datums Page Page 1 of 5
Station ID: 8664782 PUBLICATION DATE: 03/09/2004
Name: HORLBECK CREEK, WANDO RIVER
SC
NOAA Chart: 11524 Latitude: 32° 53.1' N ( 32.88500)
USGS Quad: CAINHOY Longitude: 79° 50.7' W ( -79.84500)
To reach the tidal bench marks from the boat launching ramp at the north end of
the State Highway 41 bridge over Wando River, proceed downriver by boat for
about 5 km (3 statute mi) to the north side of a long narrow slough on the east
bank of the river (approximately 0.8 km (0.5 mi) north of Horlbeck Creek). The
bench marks are along the river bank on the north side of the slough. The tide
gage and staff were on the front range signal structure NW of the slough's
mouth.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: BECK 1928
DESIGNATION: BECK
MONUMENTATION: Triangulation Station disk VM#: 4095
AGENCY: US Coast & Geodetic Survey
(USC&GS) IDB PID#: CJ0801
SETTING CLASSIFICATION: Clay pipe OPUS PID:
LATITUDE: 32° 53.1' N ( 32.88500) LONGITUDE: 79° 50.6' W ( -79.84330)
The primary bench mark is a disk set in the top of a 12-inch diameter
terra-cotta pipe filled with concrete, 91 m (300 ft) east of a red coast guard
range mark #26, 6.71 m (22.0 ft) SW of a pine tree with witness sign at the
river bank, and 0.24 m (0.8 ft) above the ground.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 8664782 PUBLICATION DATE: 03/09/2004
Name: HORLBECK CREEK, WANDO RIVER
SC
NOAA Chart: 11524 Latitude: 32° 53.1' N ( 32.88500)
USGS Quad: CAINHOY Longitude: 79° 50.7' W ( -79.84500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1 1928
DESIGNATION: 866 4782 TIDAL 1
MONUMENTATION: Reference Mark disk VM#: 4096
AGENCY: US Coast & Geodetic Survey
(USC&GS) IDB PID#: CJ1072
SETTING CLASSIFICATION: Clay pipe OPUS PID:
LATITUDE: 32° 53.1' N ( 32.88500) LONGITUDE: 79° 50.7' W ( -79.84500)
The bench mark is a disk set in the top of a 12-inch diameter terra-cotta pipe
filled with concrete, 7.01 m (23.0 ft) NNW of a triangular blaze on the most
westerly of twin oak trees at the slough bank, 6.10 m (20.0 ft) ENE of a pine
tree with witness sign at the river bank, and 0.21 m (0.7 ft) above ground
level.
BENCH MARK STAMPING: 2 1928
DESIGNATION: 866 4782 TIDAL 2
MONUMENTATION: Reference Mark disk VM#: 4097
AGENCY: US Coast & Geodetic Survey
(USC&GS) IDB PID#: CJ1073
SETTING CLASSIFICATION: Clay pipe OPUS PID:
LATITUDE: 32° 53.1' N ( 32.88500) LONGITUDE: 79° 50.7' W ( -79.84500)
The bench mark is a disk set in the top of a 12-inch diameter terra-cotta pipe
filled with concrete, 6.55 m (21.5 ft) ENE of a triangular blaze on the most
westerly of twin oak trees at the slough bank, 1.37 m (4.5 ft) NNE of the upper
edge of the bank forming the north edge of the slough, and 15 cm (0.5 ft) above
the ground.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 8664782 PUBLICATION DATE: 03/09/2004
Name: HORLBECK CREEK, WANDO RIVER
SC
NOAA Chart: 11524 Latitude: 32° 53.1' N ( 32.88500)
USGS Quad: CAINHOY Longitude: 79° 50.7' W ( -79.84500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 3 1973
DESIGNATION: 866 4782 TIDAL 3
MONUMENTATION: Tidal Station disk VM#: 4098
AGENCY: US Coast & Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 32° 53.1' N ( 32.88500) LONGITUDE: 79° 50.7' W ( -79.84500)
The bench mark is a disk set in the top of a concrete monument, 8 m (27 ft) SE
of the approximate shore line, 5.79 m (19.0 ft) east of bench mark 1 1928, 5.39
m (17.7 ft) north of bench mark 2 1928, and 0.43 m (1.4 ft) above the ground.
BENCH MARK STAMPING: NO 4 1973
DESIGNATION: 866 4782 TIDAL 4
MONUMENTATION: Tidal Station disk VM#: 4099
AGENCY: US Coast & Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 32° 53.1' N ( 32.88500) LONGITUDE: 79° 50.7' W ( -79.84500)
The bench mark is a disk set in the top of a concrete monument at the edge of
the high ground, 16 m (52 ft) NE of bench mark 1 1928, 15 m (50 ft) NE of bench
mark BECK 1928, and 0.37 m (1.2 ft) above the ground.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 8664782 PUBLICATION DATE: 03/09/2004
Name: HORLBECK CREEK, WANDO RIVER
SC
NOAA Chart: 11524 Latitude: 32° 53.1' N ( 32.88500)
USGS Quad: CAINHOY Longitude: 79° 50.7' W ( -79.84500)
T I D A L D A T U M S
Tidal datums at HORLBECK CREEK, WANDO RIVER based on:
LENGTH OF SERIES: 1 MONTH
TIME PERIOD: March 1976 - March 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 = 1.902
MEAN HIGH WATER MHW = 1.801
MEAN SEA LEVEL MSL = 0.970
MEAN TIDE LEVEL MTL = 0.932
MEAN LOW WATER MLW = 0.063
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
BECK 1928 2.140 0.339
1 1928 2.831 1.030
2 1928 2.895 1.094
NO 3 1973 3.358 1.557
NO 4 1973 2.762 0.961
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 8664782 PUBLICATION DATE: 03/09/2004
Name: HORLBECK CREEK, WANDO RIVER
SC
NOAA Chart: 11524 Latitude: 32° 53.1' N ( 32.88500)
USGS Quad: CAINHOY Longitude: 79° 50.7' W ( -79.84500)
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.