U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
PUBLICATION DATE: 01/24/1985
Station ID: 8534244 SUPERCEDED DATE: 04/21/2003
Name: GRAVELING POINT, GREAT BAY
NEW JERSEY
NOAA Chart: 12316 Latitude: 39° 32.4' N
USGS Quad: NEW GRETNA Longitude: 74° 23.2' W
To reach the tidal bench marks from the south end of Tuckerton, off U.S. Highway
9, proceed SE on Maple Avenue (Great Bay Tavern on corner), which becomes Radio
Road, for 5 miles (8 km) to the end of the road and the Great Bay Marina. The
bench marks are located along Radio Road and the tide gage and staff were
located on the Great Bay Marina bulkhead.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 4244 A 1977
MONUMENTATION: Survey Disk VM#: 2660
AGENCY: PID:
SETTING CLASSIFICATION: Galvanized Steel Rod
The bench mark is 227.5 feet (69.3 m) SE of wood utility pole #BT 173-P31631,
214.8 feet (65.5 m) SE of the centerline of Radio Road, 199.0 feet (60.7 m) east
of wood utility pole #ACE P32305, 66.4 feet (20.2 m) north of the south end of
the bulkhead, and 2.8 feet (0.9 m) west of the east face of the bulkhead of
Great Bay Marina. The bench mark is 0.2 foot (0.1 m) below ground level,
crimped to a galvanized steel rod driven 50 feet (15.2 m), and encased in PVC
pipe and a concrete kickblock.
BENCH MARK STAMPING: 4244 B 1977
MONUMENTATION: Survey Disk VM#: 2661
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Base
The bench mark is set on top of the concrete base of the flagpole at the Great
Bay Marina, 400 feet (122 m) NE of Bench Mark 4244 A 1977, 62.5 feet (19.0 m)
west of the SW corner of the 2-story wood marina building, 28.7 feet (8.7 m)
south of a gasoline station sign, 17.2 feet (5.2 m) north of the south face of
the wood bulkhead, 3.8 feet (1.2 m) north of the SW corner of the concrete base,
0.8 foot (0.2 m) SW of the flagpole, and 0.5 foot (0.2 m) above ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
PUBLICATION DATE: 01/24/1985
Station ID: 8534244 SUPERCEDED DATE: 04/21/2003
Name: GRAVELING POINT, GREAT BAY
NEW JERSEY
NOAA Chart: 12316 Latitude: 39° 32.4' N
USGS Quad: NEW GRETNA Longitude: 74° 23.2' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 4244 C 1977
MONUMENTATION: Survey Disk VM#: 2662
AGENCY: PID:
SETTING CLASSIFICATION: Galvanized Steel Rod
The bench mark is at the entrance to the Great Bay Marina, 320 feet (97.5 m) NW
of Bench Mark 4244 B 1977, 30.5 feet (9.3 m) SE of the centerline of Radio Road,
29.4 feet (9.0 m) north of the centerline of the entrance to the marina, 15.9
feet (4.8 m) SE of wood utility pole #BT 172 P31630, and 9.0 feet (2.7 m) NE of
a stop sign. The bench mark is level with the ground, crimped to a galvanized
steel rod driven 50 feet (15.2 m), and encased in PVC pipe and a concrete
kickblock.
BENCH MARK STAMPING: 4244 D 1977
MONUMENTATION: Survey Disk VM#: 2663
AGENCY: PID:
SETTING CLASSIFICATION: Galvanized Steel Rod
The bench mark is 322.3 (98.2 m) north of Bench Mark 4244 C 1977, 19.4 feet (5.9
m) east of the centerline of Radio Road, 13.4 feet (4.1 m) NW of the guy wire
anchor post supporting the wood utility pole described, and 3.3 feet (1.0 m)
east of wood utility pole #BT L401 170. The bench mark is 0.2 foot (0.1 m)
below ground level, crimped to a galvanized steel rod driven 50 feet (15.2 m),
and encased in PVC pipe and a concrete kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
PUBLICATION DATE: 01/24/1985
Station ID: 8534244 SUPERCEDED DATE: 04/21/2003
Name: GRAVELING POINT, GREAT BAY
NEW JERSEY
NOAA Chart: 12316 Latitude: 39° 32.4' N
USGS Quad: NEW GRETNA Longitude: 74° 23.2' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 4244 E 1977
MONUMENTATION: Survey Disk VM#: 2664
AGENCY: PID:
SETTING CLASSIFICATION: Galvanized Steel Rod
The bench mark is 336 feet (102.4 m) north of Bench Mark 4244 D 1977, 190.9 feet
(58.2 m) north of wood utility pole #BT 169 P31628, 19.7 feet (6.0 m) east of
the centerline of Radio Road, and 9.0 feet (2.7 m) south of wood utility pole
#BT 168 P31627. The bench mark is 0.2 foot (0.1 m) below ground level, crimped
to a galvanized steel rod driven 50 feet (15.2 m), and encased in PVC pipe and a
concrete kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
PUBLICATION DATE: 01/24/1985
Station ID: 8534244 SUPERCEDED DATE: 04/21/2003
Name: GRAVELING POINT, GREAT BAY
NEW JERSEY
NOAA Chart: 12316 Latitude: 39° 32.4' N
USGS Quad: NEW GRETNA Longitude: 74° 23.2' W
T I D A L D A T U M S
Tidal datums at GRAVELING POINT, GREAT BAY based on:
LENGTH OF SERIES: 12 MONTHS
TIME PERIOD: SEPTEMBER 1977-OCTOBER 1978
TIDAL EPOCH: 1960-1978
CONTROL TIDE STATION: 8557380 LEWES, DE
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET:
HIGHEST OBSERVED WATER LEVEL (10/14/1977) = 6.59
MEAN HIGHER HIGH WATER MHHW = 3.73
MEAN HIGH WATER MHW = 3.37
MEAN TIDE LEVEL MTL = 1.75
MEAN LOW WATER MLW = 0.13
MEAN LOWER LOW WATER MLLW = 0.00
LOWEST OBSERVED WATER LEVEL (12/10/1977) = -2.16
Bench Mark Elevation Information In FEET above:
Stamping or Designation MLLW MHW
4244 A 1977 6.19 2.82
4244 B 1977 7.90 4.53
4244 C 1977 6.39 3.02
4244 D 1977 7.31 3.94
4244 E 1977 5.51 2.14
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
PUBLICATION DATE: 01/24/1985
Station ID: 8534244 SUPERCEDED DATE: 04/21/2003
Name: GRAVELING POINT, GREAT BAY
NEW JERSEY
NOAA Chart: 12316 Latitude: 39° 32.4' N
USGS Quad: NEW GRETNA Longitude: 74° 23.2' 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 (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 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.