U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 6
Station ID: 8466375 PUBLICATION DATE: 04/29/2004
Name: GULF BEACH
CT
NOAA Chart: 12370 Latitude: 41° 12.3' N ( 41.20500)
USGS Quad: Milford Longitude: 73° 2.5' W ( -73.04170)
To reach the tidal bench marks from the intersection of Gulf Street and New
Haven Avenue in Milford, proceed south on Gulf Street for 1.9 km (1.2 mi) to 687
Gulf Street, turn right and go to the end of the driveway. The bench marks are
along Gulf Street, north of the residence at 687 Gulf Street. The tide gage and
staff were at the SE end of the pier behind the residence.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 6375 A 1987
DESIGNATION: 846 6375 A
MONUMENTATION: Tidal Station disk VM#: 2277
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Sea wall OPUS PID#: BBDJ02
LATITUDE: 41° 12.3' N ( 41.20500) LONGITUDE: 73° 2.5' W ( -73.04170)
The primary bench mark is a disk set in the top of the concrete sea wall at the
Gulf Beach parking area, near the south end, 73 m (240 ft) SW of the
intersection of Gulf Street and Old Field Lane, 1.52 m (5.0 ft) NNW of the south
end of the sea wall, 0.15 m (0.5 ft) west of the east face of the sea wall, and
0.61 m (2.0 ft) above the asphalt level of the parking lot.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 6
Station ID: 8466375 PUBLICATION DATE: 04/29/2004
Name: GULF BEACH
CT
NOAA Chart: 12370 Latitude: 41° 12.3' N ( 41.20500)
USGS Quad: Milford Longitude: 73° 2.5' W ( -73.04170)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 2 1917
DESIGNATION: TIDAL 2 STA 26
MONUMENTATION: Tidal Station disk VM#: 2274
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: LX0902
SETTING CLASSIFICATION: Granite rock OPUS PID:
LATITUDE: 41° 12.6' N ( 41.21000) LONGITUDE: 73° 2.9' W ( -73.04830)
The bench mark is a disk set flush in the top of a 2.56 m x 1.22 m x 0.91 m (8.4
ft x 4.0 ft x 3.0 ft) granite rock, at the west end of the jetty at the entrance
to Gulf Pond, 4.15 m (13.6 ft) west of the west face of the concrete foundation
of the harbor light, 1.92 m (6.3 ft) north of the south end of the rock, 0.61 m
(2.0 ft) south of the north end of the rock, and level with the beach.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 6
Station ID: 8466375 PUBLICATION DATE: 04/29/2004
Name: GULF BEACH
CT
NOAA Chart: 12370 Latitude: 41° 12.3' N ( 41.20500)
USGS Quad: Milford Longitude: 73° 2.5' W ( -73.04170)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 3 1917
DESIGNATION: TIDAL 3 STA 26
MONUMENTATION: Tidal Station disk VM#: 2275
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: LX0900
SETTING CLASSIFICATION: Granite wing wall OPUS PID:
LATITUDE: 41° 12.6' N ( 41.21000) LONGITUDE: 73° 2.8' W ( -73.04670)
The bench mark is a disk set in the top of a granite wing wall of the old steel
bridge over Gulf Pond, 22.25 m (73.0 ft) SW of the SW corner of the new concrete
bridge, 16.03 m (52.6 ft) south of the SW corner of the old bridge, 1.68 m (5.5
ft) north of the south end of the wing wall, and 1 m (4 ft) below the level of
the street.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 6
Station ID: 8466375 PUBLICATION DATE: 04/29/2004
Name: GULF BEACH
CT
NOAA Chart: 12370 Latitude: 41° 12.3' N ( 41.20500)
USGS Quad: Milford Longitude: 73° 2.5' W ( -73.04170)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: F 34 1965
DESIGNATION: F 34
MONUMENTATION: Bench Mark disk VM#: 2276
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: LX0899
SETTING CLASSIFICATION: Concrete abutment OPUS PID:
LATITUDE: 41° 12.7' N ( 41.21170) LONGITUDE: 73° 2.8' W ( -73.04670)
The bench mark is a disk set in the top SE corner of a concrete bridge abutment
of the new bridge over Gulf Pond, 8.84 m (29.0 ft) west of the NE corner of the
old bridge, 2.41 m (7.9 ft) east of the centerline of Gulf Street, 2.1 feet (0.6
m) north of the south face of the abutment, and level with the ground.
BENCH MARK STAMPING: USE 13 NO 1
DESIGNATION: 846 6375 USE 13 RM 1
MONUMENTATION: Survey disk VM#: 2279
AGENCY: US Army Corps of Engineers (USE) IDB PID#: LX0901
SETTING CLASSIFICATION: Granite wing wall OPUS PID:
LATITUDE: 41° 12.3' N ( 41.20500) LONGITUDE: 73° 2.5' W ( -73.04170)
The bench mark is a disk set in the top of a granite wing wall of the old steel
bridge over Gulf Pond, 0.85 m (2.8 ft) south of Bench Mark NO 3 1917, 0.79 m
(2.6 ft) north of the south end of the wing wall, 0.3 m (1.0 ft) west of the
east face of the wingwall, and 1.22 m (4.0 ft) below the level of the street.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 6
Station ID: 8466375 PUBLICATION DATE: 04/29/2004
Name: GULF BEACH
CT
NOAA Chart: 12370 Latitude: 41° 12.3' N ( 41.20500)
USGS Quad: Milford Longitude: 73° 2.5' W ( -73.04170)
T I D A L D A T U M S
Tidal datums at GULF BEACH based on:
LENGTH OF SERIES: 3 MONTHS
TIME PERIOD: November 1987 - January 1988
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8467150 BRIDGEPORT, BRIDGEPORT HARBOR
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 2.092
MEAN HIGH WATER MHW = 1.994
North American Vertical Datum NAVD88 = 1.108
MEAN TIDE LEVEL MTL = 1.035
MEAN SEA LEVEL MSL = 1.034
MEAN LOW WATER MLW = 0.077
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
6375 A 1987 3.449 1.455
NO 2 1917 2.570 0.576
NO 3 1917 3.321 1.327
F 34 1965 4.632 2.638
USE 13 NO 1 3.304 1.310
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 6
Station ID: 8466375 PUBLICATION DATE: 04/29/2004
Name: GULF BEACH
CT
NOAA Chart: 12370 Latitude: 41° 12.3' N ( 41.20500)
USGS Quad: Milford Longitude: 73° 2.5' W ( -73.04170)
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.