U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 8667075 PUBLICATION DATE: 02/05/2004
Name: STEAMBOAT CREEK LANDING
SC
NOAA Chart: 11522 Latitude: 32° 36.2' N ( 32.60330)
USGS Quad: EDISTO ISLAND Longitude: 80° 17.2' W ( -80.28670)
To reach the tidal bench marks the from the Post Office in Edisto Island,
proceed north on State Highway 174 for 2.9 km (1.8 mi) to State Road S- 968,
turn right onto State Road S-968 (Steamboat Landing Road) and go NNE for 2.7 km
(1.7 mi) to a dirt road, then turn right onto the dirt road and go east for 0.6
km (0.4 mi) to Dodge Plantation. The bench marks are on the plantation grounds
near an octogonal summerhouse, tennis court, and caretakers house. The tide
gauge and staff were located on an old sea wall.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 7075 A 1977
DESIGNATION: 866 7075 A TIDAL
MONUMENTATION: Tidal Station disk VM#: 6684
AGENCY: National Ocean Survey (NOS) IDB PID#: CK1792
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID:
LATITUDE: 32° 36.2' N ( 32.60330) LONGITUDE: 80° 17.2' W ( -80.28670)
The primary bench mark is a disk located at the steel sea wall, 16.15 m (53.0
ft) west of the east end of the sea wall, 10.73 m (35.2 ft) north of the center
of the door to the octogonal summerhouse, 9.39 m (30.8 ft) north of bench mark
7075 B 1977, and 2.13 m (7.0 ft) south the sea wall. The bench mark is set
level with the ground, crimped to the top of a copper-clad steel rod driven 12.2
m (40 ft) 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
Station ID: 8667075 PUBLICATION DATE: 02/05/2004
Name: STEAMBOAT CREEK LANDING
SC
NOAA Chart: 11522 Latitude: 32° 36.2' N ( 32.60330)
USGS Quad: EDISTO ISLAND Longitude: 80° 17.2' W ( -80.28670)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 7075 B 1977
DESIGNATION: 866 7075 B TIDAL
MONUMENTATION: Tidal Station disk VM#: 6685
AGENCY: National Ocean Survey (NOS) IDB PID#: CK1791
SETTING CLASSIFICATION: Brick foundation OPUS PID:
LATITUDE: 32° 36.2' N ( 32.60330) LONGITUDE: 80° 17.2' W ( -80.28670)
The bench mark is a disk set flush in the brick foundation of the octogonal
summerhouse, 11.58 m (38.0 ft) south of the sea wall, 1.22 m (4.0 ft) NNW of the
center of the door to the summerhouse, and 0.24 m (0.8 ft) NW of the NW face of
the summerhouse.
BENCH MARK STAMPING: 7075 C 1977
DESIGNATION: 866 7075 C TIDAL
MONUMENTATION: Tidal Station disk VM#: 6686
AGENCY: National Ocean Survey (NOS) IDB PID#: CK1788
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID:
LATITUDE: 32° 36.1' N ( 32.60170) LONGITUDE: 80° 17.2' W ( -80.28670)
The bench mark is a disk located at the west end of the two story caretakers
house, 84 m (276 ft) SW of bench mark 7075 B 1977, 14.72 m (48.3 ft) west of the
westernmost column on the north side of the house, and 1.34 m (4.4 ft) NW of the
NE corner of the house. The bench mark is set level with the ground, crimped to
the top of a copper-clad steel rod driven 12.2 m (40 ft) 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 5
Station ID: 8667075 PUBLICATION DATE: 02/05/2004
Name: STEAMBOAT CREEK LANDING
SC
NOAA Chart: 11522 Latitude: 32° 36.2' N ( 32.60330)
USGS Quad: EDISTO ISLAND Longitude: 80° 17.2' W ( -80.28670)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 7075 D 1977
DESIGNATION: 866 7075 D TIDAL
MONUMENTATION: Tidal Station disk VM#: 6687
AGENCY: National Ocean Survey (NOS) IDB PID#: CK1789
SETTING CLASSIFICATION: Concrete porch OPUS PID:
LATITUDE: 32° 36.1' N ( 32.60170) LONGITUDE: 80° 17.2' W ( -80.28670)
The bench mark is a disk set flush in a concrete porch supporting the steps at
the east end of the caretakers house, 41.76 m (137.0 ft) WSW of bench mark 7075
E 1977, 4.57 m (15.0 ft) SE of the NE corner of the brick patio at the
caretakers house, and 1.62 m (5.3 ft) west of the easternmost column of the
caretakers house.
BENCH MARK STAMPING: 7075 E 1977
DESIGNATION: 866 7075 E TIDAL
MONUMENTATION: Tidal Station disk VM#: 6688
AGENCY: National Ocean Survey (NOS) IDB PID#: CK1790
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID:
LATITUDE: 32° 36.2' N ( 32.60330) LONGITUDE: 80° 17.1' W ( -80.28500)
The bench mark is a disk located on the west side of the tennis court, 20.24 m
(66.4 ft) north of the SW corner of the tennis court, 18.29 m (6.0 ft) NNW of
the center of the west gate to the tennis court, and 1.13 m (3.7 ft) west of the
west edge of the tennis court. The bench mark is set level with the ground,
crimped to the top of a copper-clad steel rod driven 12.2 m (40 ft) 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 4 of 5
Station ID: 8667075 PUBLICATION DATE: 02/05/2004
Name: STEAMBOAT CREEK LANDING
SC
NOAA Chart: 11522 Latitude: 32° 36.2' N ( 32.60330)
USGS Quad: EDISTO ISLAND Longitude: 80° 17.2' W ( -80.28670)
T I D A L D A T U M S
Tidal datums at STEAMBOAT CREEK LANDING based on:
LENGTH OF SERIES: 1 YEAR
TIME PERIOD: May 1977 - April 1978
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 (06/01/1977) = 2.520
MEAN HIGHER HIGH WATER MHHW = 2.009
MEAN HIGH WATER MHW = 1.899
North American Vertical Datum NAVD88 = 1.125
MEAN SEA LEVEL MSL = 1.084
MEAN TIDE LEVEL MTL = 0.982
MEAN LOW WATER MLW = 0.064
MEAN LOWER LOW WATER MLLW = 0.000
LOWEST OBSERVED WATER LEVEL (01/09/1978) = -0.964
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
7075 A 1977 2.575 0.676
7075 B 1977 2.755 0.856
7075 C 1977 3.141 1.242
7075 D 1977 3.826 1.927
7075 E 1977 3.809 1.910
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 8667075 PUBLICATION DATE: 02/05/2004
Name: STEAMBOAT CREEK LANDING
SC
NOAA Chart: 11522 Latitude: 32° 36.2' N ( 32.60330)
USGS Quad: EDISTO ISLAND Longitude: 80° 17.2' W ( -80.28670)
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.