U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 4
Station ID: 8655151 PUBLICATION DATE: 01/21/2005
Name: CEDAR ISLAND
NORTH CAROLINA
NOAA Chart: 11550 Latitude: 35° 1.2' N
USGS Quad: NORTH BAY Longitude: 76° 18.6' W
To reach the tidal bench marks from Beaufort, proceed NE on U.S. Highway 70 and
then State Road 12 for 60 km (37 mi) to the end of the road at Cedar Island
Ferry Terminal. The bench marks are on the ferry campground and to the SW. The
tide gage and staff were located on the ferry slip.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 5151 A 1977
DESIGNATION: 865 5151 A TIDAL
MONUMENTATION: Tidal Station disk VM#: 3553
AGENCY: National Ocean Survey (NOS) PID:
SETTING CLASSIFICATION: Concrete footing
The primary bench mark is a disk set flush in a concrete footing for an antenna,
40 m (132 ft) north of the ferry operations building.
BENCH MARK STAMPING: 5151 B 1977
DESIGNATION: 865 5151 B TIDAL
MONUMENTATION: Tidal Station disk VM#: 3554
AGENCY: National Ocean Survey (NOS) PID#: AC7508
SETTING CLASSIFICATION: Concrete slab
The bench mark is a disk set flush in a concrete slab in front of the ferry
operations building, 17.37 m (57.0 ft) NW of the SE corner of the ferry ticket
operations building, 1.52 m (5.0 ft) SW of the SW corner of the operations
building, 2.59 m (8.5 ft) NE of the SW corner of the sidewalk, and 0.15 m (0.5
ft) from the mens rest room partition corner.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 4
Station ID: 8655151 PUBLICATION DATE: 01/21/2005
Name: CEDAR ISLAND
NORTH CAROLINA
NOAA Chart: 11550 Latitude: 35° 1.2' N
USGS Quad: NORTH BAY Longitude: 76° 18.6' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 5151 C 1977
DESIGNATION: 865 5151 C TIDAL
MONUMENTATION: Tidal Station disk VM#: 3555
AGENCY: National Ocean Survey (NOS) PID:
SETTING CLASSIFICATION: Concrete slab
The bench mark is a disk set flush in a concrete slab at the NE corner of the
westerly motel building, and 0.24 m (0.8 ft) from the corner.
BENCH MARK STAMPING: 5151 D 1977
DESIGNATION: 865 5151 D TIDAL
MONUMENTATION: Tidal Station disk VM#: 3556
AGENCY: National Ocean Survey (NOS) PID:
SETTING CLASSIFICATION: Concrete slab
The bench mark is a disk set flush in the north end of a concrete porch slab
located on the west side of the main motel building, and 0.09 m (1.0 ft) from
the block wall.
BENCH MARK STAMPING: 5151 E 1977
DESIGNATION: 865 5151 E TIDAL
MONUMENTATION: Tidal Station disk VM#: 3557
AGENCY: National Ocean Survey (NOS) PID#: AE5342
SETTING CLASSIFICATION: Concrete porch
The bench mark is a disk set flush in a concrete porch at the NE corner of the
shopping complex building, 0.24 m (0.8 ft) from the NE corner of the building,
and 0.24 m (0.8 ft) SW of the edge of the porch.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 4
Station ID: 8655151 PUBLICATION DATE: 01/21/2005
Name: CEDAR ISLAND
NORTH CAROLINA
NOAA Chart: 11550 Latitude: 35° 1.2' N
USGS Quad: NORTH BAY Longitude: 76° 18.6' W
T I D A L D A T U M S
Tidal datums at CEDAR ISLAND based on:
LENGTH OF SERIES: 7 MONTHS
TIME PERIOD: November 1979 - May 1980
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8656483 BEAUFORT, DUKE MARINE LAB
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER (MHHW) = 0.127
MEAN HIGH WATER (MHW) = 0.116
MEAN TIDE LEVEL (MTL) = 0.060
MEAN SEA LEVEL (MSL) = 0.036
MEAN LOW WATER (MLW) = 0.003
MEAN LOWER LOW WATER (MLLW) = 0.000
National Geodetic Vertical Datum (NGVD 29)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
5151 A 1977 1.786 1.670
5151 B 1977 1.688 1.572
5151 C 1977 1.787 1.671
5151 D 1977 1.774 1.658
5151 E 1977 1.606 1.490
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 4
Station ID: 8655151 PUBLICATION DATE: 01/21/2005
Name: CEDAR ISLAND
NORTH CAROLINA
NOAA Chart: 11550 Latitude: 35° 1.2' N
USGS Quad: NORTH BAY Longitude: 76° 18.6' W
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 (NAVD 88).
NGVD 29 is a fixed datum adopted as a national standard geodetic reference for
heights but is now considered superseded. NGVD 29 is sometimes referred to as
Sea Level Datum of 1929 or as Mean Sea Level on some early issues of Geological
Survey Topographic Quads. NGVD 29 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 NGVD 29 are available from the National
Geodetic Survey (NGS) data base via the World Wide Web at
National Geodetic Survey.
NAVD 88 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. NAVD 88 replaces NGVD 29 as the national
standard geodetic reference for heights. Bench mark elevations relative to
NAVD 88 are available from NGS through the World Wide Web at
National Geodetic Survey.
NGVD 29 and NAVD 88 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 NAVD 88 elevation is shown on the Elevations of Tidal Datums Table Referred
to MLLW only when two or more of the bench marks listed have NAVD 88 elevations.
The NAVD 88 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, NAVD 88 bench mark elevations computed indirectly from the tidal
datums elevation table may differ slightly from NAVD 88 elevations listed for
each bench mark in the NGS database.