U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 8468799 PUBLICATION DATE: 05/27/2003
Name: LONG NECK PT., LONG ISLAND SND
CT
NOAA Chart: 12368 Latitude: 41° 2.3' N ( 41.03830)
USGS Quad: NORWALK SOUTH Longitude: 73° 28.8' W ( -73.48000)
To reach the tidal bench marks from US Highway 1 and Rings End Road in Noroton,
proceed SE on Rings End Road to Pear Tree Point Road, then south on Pear Tree
Point Road to Long Neck Point Road, then south on Long Neck Point Road to the
residence at 244 Long Neck Point Road. The bench marks are in the vicinity of
244 and 245 Long Neck Point Road. The tide gauge and staff were on the concrete
T-shaped pier at 244 Long Neck Point Road.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 8799 A 1990
DESIGNATION: 846 8799 A
MONUMENTATION: Survey disk VM#: 7462
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete platform OPUS PID:
LATITUDE: 41° 2.3' N ( 41.03830) LONGITUDE: 73° 28.8' W ( -73.48000)
The primary bench mark is a disk set in the top of the SW corner of a concrete
platform at the east end of a concrete T-pier (platform is also the ceiling of a
small boat shed at 244 Long Neck Point Road), 5 m (18 ft) west of the west edge
of the lawn, 1.92 m (6.3 ft) south of the north edge of the platform, 0.37 m
(1.2 ft) east of the west edge of the platform, and 0.34 m (1.1 ft) north of the
south edge of the platform.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 8468799 PUBLICATION DATE: 05/27/2003
Name: LONG NECK PT., LONG ISLAND SND
CT
NOAA Chart: 12368 Latitude: 41° 2.3' N ( 41.03830)
USGS Quad: NORWALK SOUTH Longitude: 73° 28.8' W ( -73.48000)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 8799 B 1990
DESIGNATION: 846 8799 B
MONUMENTATION: Survey disk VM#: 7463
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete step OPUS PID:
LATITUDE: 41° 2.3' N ( 41.03830) LONGITUDE: 73° 28.8' W ( -73.48000)
The bench mark is a disk set in the top of a concrete step on the east side of
the log cabin at 244 Long Neck Point Road (log cabin is located at the waters
edge just north of the concrete T-pier), 1.13 m (3.7 ft) north of the south
edge of the upper step, 0.40 m (1.3 ft) south of the north edge, and 0.15 m (0.5
ft) east of the west edge.
BENCH MARK STAMPING: 8799 C 1990
DESIGNATION: 846 8799 C
MONUMENTATION: Survey disk VM#: 7464
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete slab OPUS PID:
LATITUDE: 41° 2.3' N ( 41.03830) LONGITUDE: 73° 28.8' W ( -73.48000)
The bench mark is a disk set in a concrete slab base of the cellar door at 244
Long Neck Point Road, 22 m (72 ft) west of the centerline of Long Neck Point
Road, 4 m (14 ft) east of the SE wall of the house, and 1.68 m (5.5 ft) south of
the south wall.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 8468799 PUBLICATION DATE: 05/27/2003
Name: LONG NECK PT., LONG ISLAND SND
CT
NOAA Chart: 12368 Latitude: 41° 2.3' N ( 41.03830)
USGS Quad: NORWALK SOUTH Longitude: 73° 28.8' W ( -73.48000)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 8799 D 1990
DESIGNATION: 846 8799 D
MONUMENTATION: Survey disk VM#: 7465
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete slab OPUS PID:
LATITUDE: 41° 2.3' N ( 41.03830) LONGITUDE: 73° 28.8' W ( -73.48000)
The bench mark is a disk set in a concrete slab set flush in the ground in the
driveway at 245 Long Neck Point Road, on the north side of the house and on the
east side of the garage doors, 14 m (45 ft) south of the south edge of the
tennis court, 2 m (7 ft) west of the front door entrance, and 1 foot (0.3 m)
north of the garage door.
BENCH MARK STAMPING: 8799 E 1990
DESIGNATION: 846 8799 E
MONUMENTATION: Survey disk VM#: 7466
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete slab OPUS PID:
LATITUDE: 41° 2.3' N ( 41.03830) LONGITUDE: 73° 28.8' W ( -73.48000)
The bench mark is a disk set in a concrete slab which is the base of a telescope
mount, at the NE corner of the residence at 245 Long Neck Point Road, 32 m (105
ft) NE of the NE corner of the house, 23 m (75 ft) east of the east edge of the
tennis court, and 2 m (6 ft) west of the hedges on the east edge of the
property.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 8468799 PUBLICATION DATE: 05/27/2003
Name: LONG NECK PT., LONG ISLAND SND
CT
NOAA Chart: 12368 Latitude: 41° 2.3' N ( 41.03830)
USGS Quad: NORWALK SOUTH Longitude: 73° 28.8' W ( -73.48000)
T I D A L D A T U M S
Tidal datums at LONG NECK PT., LONG ISLAND SND based on:
LENGTH OF SERIES: 3 MONTHS
TIME PERIOD: June 1990 - August 1990
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8518490 NEW ROCHELLE
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 2.362
MEAN HIGH WATER MHW = 2.254
MEAN TIDE LEVEL MTL = 1.163
MEAN SEA LEVEL MSL = 1.162
MEAN LOW WATER MLW = 0.071
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
8799 A 1990 6.156 3.902
8799 B 1990 6.563 4.309
8799 C 1990 7.717 5.463
8799 D 1990 8.420 6.166
8799 E 1990 7.194 4.940
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 8468799 PUBLICATION DATE: 05/27/2003
Name: LONG NECK PT., LONG ISLAND SND
CT
NOAA Chart: 12368 Latitude: 41° 2.3' N ( 41.03830)
USGS Quad: NORWALK SOUTH Longitude: 73° 28.8' W ( -73.48000)
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.