U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 8668918 PUBLICATION DATE: 05/28/2004
Name: RIBAUT ISLAND, SKULL CREEK
SC
NOAA Chart: 11516 Latitude: 32° 16.0' N ( 32.26670)
USGS Quad: PARRIS ISLAND Longitude: 80° 44.2' W ( -80.73670)
To reach the tidal bench marks from I-95, take exit 8 for US Highway 278 East to
Hilton Head Island, proceed east on US Highway 278 and cross over the bridge to
Hilton Head Island and continue east on Highway 278 (William Hilton Parkway) for
5.8 km (3.6 mi) to the entrance of Hilton Head Plantation, turn left (north) at
the traffic light, go around the circle and continue to the guard gate, then
continue north for 3.9 km (2.8 mi), turn right (east) on Sea Brook Drive and go
0.2 km (0.1 mi) and bear left at the stop sign, then continue on Whooping Crane
Way for 1.8 km (1.1 mi) to the bridge entering Ribaut Island, then proceed
straight through to Charlesfort Place and then 0.5 km (0.3 mi) to the residence
at No. 7 Charlesfort Place. The bench marks are located in the vicinity of
Charlesfort Place and Ribaut Drive. The tide gage and staff were located on a
private pier behind No. 7 Charlesfort Place.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 8918 H 1995
DESIGNATION: 8918 H TIDAL
MONUMENTATION: Tidal Station disk VM#: 13305
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 32° 16.0' N ( 32.26670) LONGITUDE: 80° 44.2' W ( -80.73670)
The primary bench mark is a disk located on the beach just north of the property
line at 7 Charlesfort Place, 18.3 m (60.2 ft) NE of the SW end of the pier on
the property, 12.7 m (41.6 ft) east of a 33 cm (13 inch) diameter pine tree, and
8.2 m (27.0 ft) NE of the NE corner of a square swimming pool. The bench mark
is set at ground level, crimped to the top of a stainless steel rod driven 13.4
m (44 ft) to refusal, and encased in a 6-inch PVC pipe.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 8668918 PUBLICATION DATE: 05/28/2004
Name: RIBAUT ISLAND, SKULL CREEK
SC
NOAA Chart: 11516 Latitude: 32° 16.0' N ( 32.26670)
USGS Quad: PARRIS ISLAND Longitude: 80° 44.2' W ( -80.73670)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 8918 F 1981
DESIGNATION: 866 8918 F TIDAL
MONUMENTATION: Tidal Station disk VM#: 4540
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Near pine tree OPUS PID:
LATITUDE: 32° 16.0' N ( 32.26670) LONGITUDE: 80° 44.2' W ( -80.73670)
The bench mark is a disk on the SW tip of Ribaut Island near a lone pine tree,
20.4 feet (6.2 m) ESE of the shoreline, 9.0 feet (2.7 m) east of a lone pine
tree, 2.0 feet (0.6 m) WNW of a wooden witness post, and 0.5 foot (0.2 m) above
ground level.
BENCH MARK STAMPING: 8918 J 1995
DESIGNATION: 8918 J TIDAL
MONUMENTATION: Tidal Station disk VM#: 13306
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete curb OPUS PID:
LATITUDE: 32° 16.0' N ( 32.26670) LONGITUDE: 80° 44.2' W ( -80.73670)
The bench mark is a disk set in a concrete curb on the west side of Charlesfort
Place, 34.1 m (112.2 ft) SW of a yellow fire hydrant marked Mueller 5 1-4 1988,
15.4 m (50.6 ft) NE of a green underground power cable box, and 3.8 m (12.5 ft)
NE of the centerline of Charlesfort Place.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 8668918 PUBLICATION DATE: 05/28/2004
Name: RIBAUT ISLAND, SKULL CREEK
SC
NOAA Chart: 11516 Latitude: 32° 16.0' N ( 32.26670)
USGS Quad: PARRIS ISLAND Longitude: 80° 44.2' W ( -80.73670)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 8918 K 1995
DESIGNATION: 8918 K TIDAL
MONUMENTATION: Tidal Station disk VM#: 13307
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete walkway OPUS PID:
LATITUDE: 32° 16.0' N ( 32.26670) LONGITUDE: 80° 44.2' W ( -80.73670)
The bench mark is a disk set in a concrete walkway circling the community
swimming pool area on Ribaut Island, 15.2 m (50.0 ft) north of a 0.76 m (2.5 ft)
diameter oak tree, 12.8 m (42.0 ft) east of a stop sign at the corner of Ribaut
Drive and Charlesfort Place, and 0.6 m (2.0 ft) ENE of a yellow fire hydrant
marked Mueller 5 1-4 1986.
BENCH MARK STAMPING: 8918 L 1995
DESIGNATION: 8918 L TIDAL
MONUMENTATION: Tidal Station disk VM#: 13308
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete curb OPUS PID:
LATITUDE: 32° 16.0' N ( 32.26670) LONGITUDE: 80° 44.2' W ( -80.73670)
The bench mark is a disk set in the concrete curb on the south side of Ribaut
Drive, 35.3 m (115.8 ft) west of a green underground cable box, 3.8 m (12.5 ft)
SW of the centerline of Ribaut Drive, and 1.8 m (6.0 ft) north of a yellow fire
hydrant marked Mueller 5 1-4 1988.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 8668918 PUBLICATION DATE: 05/28/2004
Name: RIBAUT ISLAND, SKULL CREEK
SC
NOAA Chart: 11516 Latitude: 32° 16.0' N ( 32.26670)
USGS Quad: PARRIS ISLAND Longitude: 80° 44.2' W ( -80.73670)
T I D A L D A T U M S
Tidal datums at RIBAUT ISLAND, SKULL CREEK based on:
LENGTH OF SERIES: 2 MONTHS
TIME PERIOD: January 1997 - February 1997
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8670870 FORT PULASKI, SAVANNAH RIVER
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 2.252
MEAN HIGH WATER MHW = 2.142
MEAN SEA LEVEL MSL = 1.187
MEAN TIDE LEVEL MTL = 1.102
MEAN LOW WATER MLW = 0.061
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
8918 H 1995 2.874 0.732
8918 F 1981 3.047 0.905
8918 J 1995 3.179 1.037
8918 K 1995 4.092 1.950
8918 L 1995 3.813 1.671
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 8668918 PUBLICATION DATE: 05/28/2004
Name: RIBAUT ISLAND, SKULL CREEK
SC
NOAA Chart: 11516 Latitude: 32° 16.0' N ( 32.26670)
USGS Quad: PARRIS ISLAND Longitude: 80° 44.2' W ( -80.73670)
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.