U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 6
Station ID: 8669133 PUBLICATION DATE: 02/05/2004
Name: SKULL CREEK SOUTH
SC
NOAA Chart: 11516 Latitude: 32° 13.4' N ( 32.22330)
USGS Quad: BLUFFTON Longitude: 80° 46.3' W ( -80.77170)
To reach the tidal bench marks from the intersection of U.S. Highway 46 and
Calhoun Street (S-7-11) in Bluffton, proceed east, then north on U.S. Highway 46
for 3.1 km (1.9 mi), then turn right and proceed SE on U.S. Highway 278 for 6.6
km (4.1 mi), then turn left and proceed north on Jenkins Island Road (S-7-298)
for 0.6 km (0.4 mi) to the dead end in the Hilton Head Harbor Marina parking
lot. The tidal bench marks are along the paved road and parking lot. The tide
gage and staff were on the north side of the pier behind the convenience store
and tackle shop.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 9133 C 1978
DESIGNATION: 866 9133 C TIDAL
MONUMENTATION: Tidal Station disk VM#: 4553
AGENCY: National Ocean Survey (NOS) IDB PID#: CK2037
SETTING CLASSIFICATION: Galvanized steel rod OPUS PID:
LATITUDE: 32° 13.4' N ( 32.22330) LONGITUDE: 80° 46.2' W ( -80.77000)
The primary bench mark is a disk located along the north side of the paved road
near the marina, 31 m (101 ft) SE of the SW end of the narrow part of a wooden
dock, 25.09 m (82.3 ft) ENE of an unnumbered service pole leading to the sales
office of Outdoor Resorts, 10.21 m (33.5 ft) NE of the centerline of the paved
road, 1.98 m (6.5 ft) SSW of power pole #SPC 51-5-85 with transformer, 1.83 m
(6.0 ft) SSW of a 0.61 m (2.0 ft) diameter palmetto tree, and 1.34 m (4.4 ft)
south of a metal witness post. The bench mark is crimped to the top of a
galvanized steel rod driven 8.5 m (28 ft) to refusal, and encased in a PVC pipe
and a concrete kickblock. NOTE: The bench mark was not found in 1996.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 6
Station ID: 8669133 PUBLICATION DATE: 02/05/2004
Name: SKULL CREEK SOUTH
SC
NOAA Chart: 11516 Latitude: 32° 13.4' N ( 32.22330)
USGS Quad: BLUFFTON Longitude: 80° 46.3' W ( -80.77170)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 9133 E 1978
DESIGNATION: 866 9133 E TIDAL
MONUMENTATION: Tidal Station disk VM#: 4554
AGENCY: National Ocean Survey (NOS) IDB PID#: CK2035
SETTING CLASSIFICATION: Galvanized steel rod OPUS PID:
LATITUDE: 32° 13.3' N ( 32.22170) LONGITUDE: 80° 46.2' W ( -80.77000)
The bench mark is a disk located on the east side of the paved road leading to
the marina, 8.90 m (29.2 ft) SW of power pole #11-80-SPP-8H-5-35 with
transformer 10-H, 8.84 m (29.0 ft) NW of a 0.52 m (1.7 ft) diameter palmetto
tree, 6.31 m (20.7 ft) south of a twin trunk tree with a low Y at the base, 5.94
m (19.5 ft) NE of the centerline of the paved road, 5.79 m (19.0 ft) north of a
South Carolina Highway Department sign stating ROAD ENDS, 1.52 m (5.0 ft) west
of the edge of the maintained shoulder, and 0.27 m (0.9 ft) west of a metal
witness post. The bench mark is crimped to the top of a galvanized steel rod
driven 8.5 m (28 ft) to refusal, and encased in a PVC pipe and a concrete
kickblock. NOTE: The bench mark was not found in 1996.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 6
Station ID: 8669133 PUBLICATION DATE: 02/05/2004
Name: SKULL CREEK SOUTH
SC
NOAA Chart: 11516 Latitude: 32° 13.4' N ( 32.22330)
USGS Quad: BLUFFTON Longitude: 80° 46.3' W ( -80.77170)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 9133 F 1981
DESIGNATION: 866 9133 F TIDAL
MONUMENTATION: Tidal Station disk VM#: 4555
AGENCY: National Ocean Survey (NOS) IDB PID#: CK2036
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 32° 13.4' N ( 32.22330) LONGITUDE: 80° 46.3' W ( -80.77170)
The bench mark is a disk set in a concrete monument in the center of a
landscaped traffic island between a boat storage shed and the marina sales
office, 47.40 m (155.5 ft) SW of the west corner railing of a large wooden
fishing pier, 21 m (69 ft) east of the NE corner of the boat storage shed, 17.80
m (58.4 ft) SW of the SW corner of the Outdoors Resort Sales Office trailer,
6.61 m (21.7 ft) SSE of the NW end of the landscaped traffic island, 4.11 m
(13.5 ft) SE of a 1 m (3 ft) diameter oak tree, 3.35 m (11.0 ft) NW of a 0.61 m
(2.0 ft) diameter palmetto tree, 3.32 m (10.9 ft) SE of the perpendicular curb
of the landscaped traffic island, 3.26 m (10.7 ft) NW of the perpendicular curb
of the landscaped traffic island, and 0.06 m (0.2 ft) above grade.
BENCH MARK STAMPING: 9133 G 1981
DESIGNATION: 866 9133 G TIDAL
MONUMENTATION: Tidal Station disk VM#: 4556
AGENCY: National Ocean Survey (NOS) IDB PID#: CK2033
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 32° 13.1' N ( 32.21830) LONGITUDE: 80° 46.1' W ( -80.76830)
The bench mark is a disk set in a concrete monument at the intersection of the
paved road and U.S. Highway 278, 27.55 m (90.4 ft) WNW of the centerline of the
paved road, 16.31 m (53.5 ft) north of the centerline of the westbound lane of
U.S. Highway 278, 10.52 m (34.5 ft) west of a 0.61 m (2.0 ft) diameter pine tree
with a square blaze, 1.22 m (4.0 ft) NNE of power pole #EB 479-SPPH 535, 0.52 m
(1.7 ft) west of a metal witness post, and at ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 6
Station ID: 8669133 PUBLICATION DATE: 02/05/2004
Name: SKULL CREEK SOUTH
SC
NOAA Chart: 11516 Latitude: 32° 13.4' N ( 32.22330)
USGS Quad: BLUFFTON Longitude: 80° 46.3' W ( -80.77170)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 9133 J 1981
DESIGNATION: 866 9133 J TIDAL
MONUMENTATION: Tidal Station disk VM#: 4557
AGENCY: National Ocean Survey (NOS) IDB PID#: CK2034
SETTING CLASSIFICATION: Galvanized steel rod OPUS PID:
LATITUDE: 32° 13.2' N ( 32.22000) LONGITUDE: 80° 46.1' W ( -80.76830)
The bench mark is a disk located on the east side of the road leading to the
marina near the most southerly pole of a major power line, 22.31 m (73.2 ft) SE
of the centerline of the paved road, 15.03 m (49.3 ft) NNE of a 0.37 m (1.2 ft)
diameter elm tree with a square blase, 4.66 m (15.3 ft) NE of the easternmost
0.40 m (1.3 ft) creosoted pile of a dual pile power line structure, 0.85 m (2.8
ft) WNW of the westernmost pile of a dual pile power line structure, and 0.43 m
(1.4 ft) north of a metal witness post. The bench mark is set 0.03 m (0.1 ft)
below grade, crimped to the top of a galvanized steel rod driven 14.6 m (48 ft),
and encased in a PVC pipe and concrete kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 6
Station ID: 8669133 PUBLICATION DATE: 02/05/2004
Name: SKULL CREEK SOUTH
SC
NOAA Chart: 11516 Latitude: 32° 13.4' N ( 32.22330)
USGS Quad: BLUFFTON Longitude: 80° 46.3' W ( -80.77170)
T I D A L D A T U M S
Tidal datums at SKULL CREEK SOUTH based on:
LENGTH OF SERIES: 1 YEAR
TIME PERIOD: May 1978 - April 1979
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 (09/04/1979) = 3.265
MEAN HIGHER HIGH WATER MHHW = 2.408
MEAN HIGH WATER MHW = 2.287
North American Vertical Datum NAVD88 = 1.344
MEAN SEA LEVEL MSL = 1.270
MEAN TIDE LEVEL MTL = 1.178
MEAN LOW WATER MLW = 0.069
MEAN LOWER LOW WATER MLLW = 0.000
LOWEST OBSERVED WATER LEVEL (04/27/1979) = -1.106
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
9133 C 1978 4.139 1.852
9133 E 1978 3.893 1.606
9133 F 1981 4.506 2.219
9133 G 1981 6.355 4.068
9133 J 1981 5.577 3.290
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 6
Station ID: 8669133 PUBLICATION DATE: 02/05/2004
Name: SKULL CREEK SOUTH
SC
NOAA Chart: 11516 Latitude: 32° 13.4' N ( 32.22330)
USGS Quad: BLUFFTON Longitude: 80° 46.3' W ( -80.77170)
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.