U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 4
PUBLICATION DATE: 06/28/1988
Station ID: 8537614 SUPERCEDED DATE: 04/21/2003
Name: ARTIFICIAL ISLAND, DELAWARE RIVER
NEW JERSEY
NOAA Chart: 12311 Latitude: 39° 27.7' N
USGS Quad: TAYLORS BRIDGE Longitude: 75° 31.9' W
To reach the tidal bench marks from the junction of State Highway 49 and
Hancocks Bridge Road in Salem, proceed 4.6 miles (7.4 km) south on Hancocks
Bridge Road to the intersection at Alloway Creek Road (plant entrance road),
turn right, then north 5.5 miles (8.8 km) to the Y junction of Hope Creek and
Salem Power Plant, and bear left then 0.8 miles (1.3 km) towards the Salem
Nuclear Power Plant and Visitors Center on Artificial Island. The bench marks
are in the vicinity of the Visitors Center. The tide gage and staff were on the
dock across from the Visitors Center.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 7614 A 1977
MONUMENTATION: Survey Disk VM#: 2801
AGENCY: PID:
SETTING CLASSIFICATION: Galvanized Steel Rod
The bench mark is located 41.7 feet (12.7 m) NE of the SE corner of the Visitors
Center Building, 36.0 feet (11.0 m) south of the centerline of the entrance
road, 23.6 feet (7.2 m) west of the west edge of the helipad, and 12.1 feet (3.7
m) east of the walkway leading to the dock. The bench mark is 0.3 foot (0.1 m)
below ground level, crimped to a galvanized steel rod driven 50 feet (15 m) to
refusal, and encased in a 4-inch PVC pipe and concrete kickblock.
BENCH MARK STAMPING: 7614 D 1977
MONUMENTATION: Survey Disk VM#: 2802
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Footing
The bench mark is set in the SW concrete footing of power cable tower #1/1 5024,
400 feet (122 m) north of the north side of the entrance road, 34.8 feet (10.6
m) east of the north-south portion of the chainlink fence, 21.4 feet (6.5 m)
north of the chainlink fence paralleling the entrance road, 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 4
PUBLICATION DATE: 06/28/1988
Station ID: 8537614 SUPERCEDED DATE: 04/21/2003
Name: ARTIFICIAL ISLAND, DELAWARE RIVER
NEW JERSEY
NOAA Chart: 12311 Latitude: 39° 27.7' N
USGS Quad: TAYLORS BRIDGE Longitude: 75° 31.9' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 7614 E 1977
MONUMENTATION: Survey Disk VM#: 2803
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Footing
The bench mark is set in the SE concrete footing on power cable tower #1/1 5023,
187 feet (57 m) NE of Bench Mark 7614 D 1977, 111.5 feet (34.0 m) east of the
north-south portion of the 8.0 feet (2.4 m) high chainlink fence, 66.2 feet
(20.2 m) SW of the south gate post at the entrance to the parking area, and 2.0
feet (0.6 m) SW of the steel column member of the SE corner of the tower.
BENCH MARK STAMPING: 7614 F 1980
MONUMENTATION: Survey Disk VM#: 2804
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Footing
The bench mark is set in the SE corner of the SE concrete footing of power cable
tower #1/1 5105, the third tower north of the entrance road to the power plant,
191 feet (58 m) east of the easternmost chainlink fence around the plant, 62.0
feet (49.4 m) north of the centerline of the asphalt road to contractors site
#1, and 1.0 foot (0.3 m) above ground level.
BENCH MARK STAMPING: 7614 F 1983
MONUMENTATION: Survey Disk VM#: 2805
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Foundation
The bench mark is set in a concrete fence support pad, 73.7 feet (22.5 m) NE of
the NE corner of the chainlink fence surrounding a fuel storage tank at the east
end of helipad (south of the heli-pilots lounge), 27.2 feet (8.3 m) north of the
centerline of the entrance road, and 16.3 feet (5.0 m) NE of the fire hydrant
next to a red fire hose storage box.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 4
PUBLICATION DATE: 06/28/1988
Station ID: 8537614 SUPERCEDED DATE: 04/21/2003
Name: ARTIFICIAL ISLAND, DELAWARE RIVER
NEW JERSEY
NOAA Chart: 12311 Latitude: 39° 27.7' N
USGS Quad: TAYLORS BRIDGE Longitude: 75° 31.9' W
T I D A L D A T U M S
Tidal datums at ARTIFICIAL ISLAND, DELAWARE RIVER based on:
LENGTH OF SERIES: 18 MONTHS
TIME PERIOD: JUNE 1979-MARCH 1981
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 (12/21/1977) = 9.46
MEAN HIGHER HIGH WATER MHHW = 6.54
MEAN HIGH WATER MHW = 6.12
MEAN TIDE LEVEL MTL = 3.16
MEAN LOW WATER MLW = 0.19
MEAN LOWER LOW WATER MLLW = 0.00
LOWEST OBSERVED WATER LEVEL (12/25/1980) = -3.11
Bench Mark Elevation Information In FEET above:
Stamping or Designation MLLW MHW
7614 A 1977 16.70 10.58
7614 D 1977 17.70 11.58
7614 E 1977 17.65 11.53
7614 F 1980 17.73 11.61
7614 F 1983 17.39 11.27
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 4
PUBLICATION DATE: 06/28/1988
Station ID: 8537614 SUPERCEDED DATE: 04/21/2003
Name: ARTIFICIAL ISLAND, DELAWARE RIVER
NEW JERSEY
NOAA Chart: 12311 Latitude: 39° 27.7' N
USGS Quad: TAYLORS BRIDGE Longitude: 75° 31.9' 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.