U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 6
Station ID: 8467373 PUBLICATION DATE: 04/01/2004
Name: BLACK ROCK HARBOR, CEDAR CREEK
CT
NOAA Chart: 12369 Latitude: 41° 9.4' N ( 41.15670)
USGS Quad: BRIDGEPORT Longitude: 73° 12.8' W ( -73.21330)
To reach the bench marks from I-95 North Exit 26 - Wordin Avenue, turn right
onto Wordin Avenue and proceed SW for 0.6 km (0.4 mi) to Hancock Avenue, then
left and continue south for less than 0.2 km (0.1 mi) to Osborne Street, then
right and go west for 0.2 km (0.1 mi) To Bostwick Avenue, then left and continue
south for 0.5 km (0.3 mi) to the Captain's Cove Seaport marina. The bench marks
are located along Bostwick Avenue and on the marina property, and the tide gage
was located at the east corner of the Harbormaster's building on the commercial
dock.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 7373 C 2003
DESIGNATION: 846 7373 C
MONUMENTATION: Tidal Station disk VM#: 17126
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Sludge tank foundation OPUS PID:
LATITUDE: 41° 9.5' N ( 41.15830) LONGITUDE: 73° 12.8' W ( -73.21330)
In Black Rock, on the property of the Bridgeport East Side Treatment Plant at
205 Bostwick Avenue, the primary bench mark is a disk set in the SW corner of
the concrete foundation for the sludge tanks at the SW end of the treatment
plant property, 21.00 m (68.9 ft) west of lamp post 1375, 19.69 m (64.6 ft)
north of the SW end of the metal gate to the sludge tanks, and 1.63 m (5.3 ft)
above ground.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 6
Station ID: 8467373 PUBLICATION DATE: 04/01/2004
Name: BLACK ROCK HARBOR, CEDAR CREEK
CT
NOAA Chart: 12369 Latitude: 41° 9.4' N ( 41.15670)
USGS Quad: BRIDGEPORT Longitude: 73° 12.8' W ( -73.21330)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 7373 A 2003
DESIGNATION: 846 7373 A
MONUMENTATION: Tidal Station disk VM#: 17317
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete loading dock OPUS PID:
LATITUDE: 41° 9.5' N ( 41.15830) LONGITUDE: 73° 12.8' W ( -73.21330)
In Black Rock, at the Captain's Cove Seaport marina, the bench mark is a disk
set in the concrete loading dock of the marina restaurant, 23.5 m (77 ft) west
of the NW corner of the marina office, 21.4 m (70 ft) SW of a lamp post in the
parking lot behind the restaurant, and 1.04 m (3.4 ft) north of the NE corner of
the top step on the loading dock.
BENCH MARK STAMPING: 7373 B 2003
DESIGNATION: 846 7373 B
MONUMENTATION: Tidal Station disk VM#: 17318
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete foundation OPUS PID#: BBDD47
LATITUDE: 41° 9.5' N ( 41.15830) LONGITUDE: 73° 12.8' W ( -73.21330)
In Black Rock, at the Captain's Cove Seaport marina, the bench mark is a disk
set in the concrete foundation of a sewer access with water meter box located in
the center of the marina parking lot, 52.61 m (172.6 ft) SE of the south corner
of the blue house with a plaque stating "1893 Richard Duddon House", 45.86 m
(160.5 ft) west of a lamp post in the parking lot, and 0.90 m (3.0 ft) north of
the NE corner of the raised foundation of the sewer access.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 6
Station ID: 8467373 PUBLICATION DATE: 04/01/2004
Name: BLACK ROCK HARBOR, CEDAR CREEK
CT
NOAA Chart: 12369 Latitude: 41° 9.4' N ( 41.15670)
USGS Quad: BRIDGEPORT Longitude: 73° 12.8' W ( -73.21330)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 7373 D 2003
DESIGNATION: 846 7373 D
MONUMENTATION: Tidal Station disk VM#: 17319
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Pavement OPUS PID:
LATITUDE: 41° 9.6' N ( 41.16000) LONGITUDE: 73° 12.7' W ( -73.21170)
In Black Rock, the bench mark is a disk set in the pavement at the entrance to
the Cedar Marina at 86 Bostwick Avenue, 15.20 m (49.9 ft) south of a yellow fire
hydrant, 10.13 m (33.2 ft) SSW of a green metal post holding a Cedar Marina
sign, and 3.00 m (9.8 ft) north of lamp post 8671.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 6
Station ID: 8467373 PUBLICATION DATE: 04/01/2004
Name: BLACK ROCK HARBOR, CEDAR CREEK
CT
NOAA Chart: 12369 Latitude: 41° 9.4' N ( 41.15670)
USGS Quad: BRIDGEPORT Longitude: 73° 12.8' W ( -73.21330)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 11.11 L 2 1922
DESIGNATION: L 2
MONUMENTATION: Survey disk VM#: 17320
AGENCY: US Geological Survey (USGS) IDB PID#: LX0837
SETTING CLASSIFICATION: Building foundation OPUS PID:
LATITUDE: 41° 9.6' N ( 41.16000) LONGITUDE: 73° 12.8' W ( -73.21330)
In Black Rock, on the property of the Bridgeport East Side Treatment Plant at
205 Bostwick Avenue, the bench mark is a disk set in the foundation of the brick
pump house building, 29.86 m (98.0 ft) NW of the western corner of the bottom
step of the Control Building, 10.73 m (35.2 ft) east of the SW corner of the
pump house, 1.76 m (5.8 ft) east of the SE corner of the bottom step of the pump
house, and 0.42 m (1.4 ft) south of the south wall of the brick building.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 6
Station ID: 8467373 PUBLICATION DATE: 04/01/2004
Name: BLACK ROCK HARBOR, CEDAR CREEK
CT
NOAA Chart: 12369 Latitude: 41° 9.4' N ( 41.15670)
USGS Quad: BRIDGEPORT Longitude: 73° 12.8' W ( -73.21330)
T I D A L D A T U M S
Tidal datums at BLACK ROCK HARBOR, CEDAR CREEK based on:
LENGTH OF SERIES: 3 MONTHS
TIME PERIOD: July 2003 - September 2003
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 = 2.237
MEAN HIGH WATER MHW = 2.134
MEAN SEA LEVEL MSL = 1.107
MEAN TIDE LEVEL MTL = 1.105
MEAN LOW WATER MLW = 0.076
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
7373 C 2003 7.812 5.678
7373 A 2003 5.471 3.337
7373 B 2003 6.356 4.222
7373 D 2003 3.752 1.618
11.11 L 2 1922 4.183 2.049
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 6
Station ID: 8467373 PUBLICATION DATE: 04/01/2004
Name: BLACK ROCK HARBOR, CEDAR CREEK
CT
NOAA Chart: 12369 Latitude: 41° 9.4' N ( 41.15670)
USGS Quad: BRIDGEPORT Longitude: 73° 12.8' W ( -73.21330)
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.