U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 6
Station ID: 8469198 PUBLICATION DATE: 06/20/2016
Name: STAMFORD, STAMFORD HARBOR
CT
NOAA Chart: 12364 Latitude: 41° 2.3' N ( 41.03830)
USGS Quad: Stamford Longitude: 73° 32.8' W ( -73.54670)
To reach the tidal bench marks from the intersection of U. S. Highway 1 (Tresser
Boulevard) and State Highway 137 (Washington Boulevard) in Stamford, proceed
south on Washington Boulevard for 1.0 km (0.6 mi) to Atlantic Street. Turn right
and proceed west on Atlantic Street for 0.13 km (0.08 mi) to an access road for
the Sprague Energy Facility. Turn right and proceed north 60 m (190 ft) to a
security gate. The bench marks are located within a 1.0 km (0.6 mi) radius to
the north and northwest of the tide station. The tide station is located on the
southernmost concrete pier at the Sprague Facility.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 9198 A 2015
DESIGNATION: 846 9198 A
MONUMENTATION: DJ VM#: 21489
AGENCY: National Ocean Service IDB PID#:
SETTING CLASSIFICATION: In rock outcrop OPUS PID:
LATITUDE: 41° 2.6' N ( 41.04286) LONGITUDE: 73° 32.7' W ( -73.54436)
The primary bench mark is a disk set in a bedrock outcrop on the N side of the
Sprague facility along a set of stairs leading to a man gate, 19.59 m (64.3 ft)
E of a power pole numbered clnp-17664, 5.91 m (19.4 ft) NNE of the SE corner of
a brick building (slant distance), 3.38 m (11.1 ft) SSW of the S post of the man
gate at the top of the stairs, 1.60 m (5.2 ft) SW of the S end of a 1.8 m (6.0
ft) tall concrete retaining wall and 0.26 m (0.9 ft) SW of the W edge of the
steps.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 6
Station ID: 8469198 PUBLICATION DATE: 06/20/2016
Name: STAMFORD, STAMFORD HARBOR
CT
NOAA Chart: 12364 Latitude: 41° 2.3' N ( 41.03830)
USGS Quad: Stamford Longitude: 73° 32.8' W ( -73.54670)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 9198 B 2015
DESIGNATION: 846 9198 B
MONUMENTATION: DJ VM#: 21490
AGENCY: National Ocean Service IDB PID#:
SETTING CLASSIFICATION: Mat foundations OPUS PID:
LATITUDE: 41° 2.6' N ( 41.04267) LONGITUDE: 73° 32.5' W ( -73.54231)
The bench mark is a disk set in a 21 m (68.9 ft) by 11 m (36.1 ft) concrete
apron to the Stamford S end fire rescue building, 35.24 m (115.6 ft) W of a
utility pole on Atlantic avenue just N of a driveway, 25.13 m (82.4 ft) E of a
flagpole, 24.56 m (80.6 ft) WNW of a fire hydrant on Atlantic street, 10.29 m
(33.8 ft) N of the SE corner of the apron, 0.79 m (2.6 ft) WNW of the SE corner
of the firehouse, 0.70 m (2.3 ft) NW of the E edge of the apron and about 0.67 m
(2.2 ft) above the pavement.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 6
Station ID: 8469198 PUBLICATION DATE: 06/20/2016
Name: STAMFORD, STAMFORD HARBOR
CT
NOAA Chart: 12364 Latitude: 41° 2.3' N ( 41.03830)
USGS Quad: Stamford Longitude: 73° 32.8' W ( -73.54670)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: G 1 ELEV 23.983 FT 1922
DESIGNATION: G 1
MONUMENTATION: DB VM#: 21491
AGENCY: US Coast & Geodetic Survey IDB PID#: LX1185
SETTING CLASSIFICATION: Light structures (other than those
listed below) OPUS PID:
LATITUDE: 41° 3.0' N ( 41.04967) LONGITUDE: 73° 32.4' W ( -73.53967)
The bench mark is a disk set in a granite footing block at the SE corner of
large building which was a U.S. post office, 15.15 m (49.7 ft) S of a flagpole,
10.00 m (32.8 ft) N of the centerline of Federal street, 7.16 m (23.5 ft) W of
the curb edge of Atlantic street, 6.35 m (20.8 ft) S of the landing of granite
steps, 5.17 m (17.0 ft) NW of a crosswalk sign at the NW corner of federal
street and Atlantic street, 0.70 m (2.3 ft) N of the SE corner of the old post
office building and 1.12 m (3.7 ft) below the top of the granite parapet wall.
BENCH MARK STAMPING: 9198 C 2015
DESIGNATION: 846 9198 C
MONUMENTATION: DJ VM#: 21492
AGENCY: National Ocean Service IDB PID#:
SETTING CLASSIFICATION: Abutments and piers of large bridges OPUS PID#: BBDV81
LATITUDE: 41° 2.6' N ( 41.04414) LONGITUDE: 73° 32.7' W ( -73.54475)
The bench mark is a disk set in the NE wing wall of the Pulaski street bridge
over the Rippowam river, 29.50 m (96.8 ft) SSW of the SW corner of a parking
garage building, 22.81 m (74.8 ft) W of the decorative light E of the Pulaski
street bridge, 2.25 m (7.4 ft) N of the curb edge of Pulaski street, 1.21 m (4.0
ft) NNE of the E end of an aluminum guard rail, 0.50 m (1.6 ft) S from the N end
of the parapet wall and about 0.70 m (2.3 ft) above the level of sidewalk.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 6
Station ID: 8469198 PUBLICATION DATE: 06/20/2016
Name: STAMFORD, STAMFORD HARBOR
CT
NOAA Chart: 12364 Latitude: 41° 2.3' N ( 41.03830)
USGS Quad: Stamford Longitude: 73° 32.8' W ( -73.54670)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: C 32 1965
DESIGNATION: C 32
MONUMENTATION: DB VM#: 21493
AGENCY: US Coast & Geodetic Survey IDB PID#: LX1177
SETTING CLASSIFICATION: Abutments and piers of large bridges OPUS PID:
LATITUDE: 41° 2.7' N ( 41.04447) LONGITUDE: 73° 33.1' W ( -73.55142)
The bench mark is a disk set in the SW corner of a concrete parapet wall which
is part of a large retaining wall, 16.65 m (54.6 ft) NNE of a fire hydrant on
the N side of Jackson street, 16.35 m (53.6 ft) N of the curb edge of Jackson
street, 15.50 m (50.9 ft) N of a power pole at the corner of Jackson street and
Fairfield avenue, 2.07 m (6.8 ft) WSW of the curb edge of Fairfield avenue, 0.12
m (0.4 ft) NNW of the S end of the parapet wall and about 0.64 m (2.1 ft) above
the sidewalk.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 6
Station ID: 8469198 PUBLICATION DATE: 06/20/2016
Name: STAMFORD, STAMFORD HARBOR
CT
NOAA Chart: 12364 Latitude: 41° 2.3' N ( 41.03830)
USGS Quad: Stamford Longitude: 73° 32.8' W ( -73.54670)
T I D A L D A T U M S
Tidal datums at STAMFORD, STAMFORD HARBOR based on:
LENGTH OF SERIES: 4 MONTHS
TIME PERIOD: May 2015 - August 2015
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 = 2.368
MEAN HIGH WATER MHW = 2.259
North American Vertical Datum NAVD88 = 1.230
MEAN SEA LEVEL MSL = 1.171
MEAN TIDE LEVEL MTL = 1.166
MEAN LOW WATER MLW = 0.073
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
9198 A 2015 7.996 5.737
9198 B 2015 5.719 3.460
G 1 ELEV 23.983 FT 1922 8.209 5.950
9198 C 2015 7.928 5.669
C 32 1965 29.119 26.860
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 6
Station ID: 8469198 PUBLICATION DATE: 06/20/2016
Name: STAMFORD, STAMFORD HARBOR
CT
NOAA Chart: 12364 Latitude: 41° 2.3' N ( 41.03830)
USGS Quad: Stamford Longitude: 73° 32.8' W ( -73.54670)
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.