U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 8468609 PUBLICATION DATE: 04/21/2003
Name: ROWAYTON, FIVEMILE RIVER
CT
NOAA Chart: 12368 Latitude: 41° 3.9' N ( 41.06500)
USGS Quad: NORWALK SOUTH Longitude: 73° 26.7' W ( -73.44500)
To reach the tidal bench marks from northbound Exit 14 on Interstate 95 in
Norwalk, turn right on Fairfield Avenue and go 1.0 km (0.6 mi), then turn left
on Washington Street for 0.3 km (0.2 mi), then turn right on Route 136 (South
Main Street) and continue 7.2 km (4.5 mi) to the intersection of McKinley Avenue
and Rowayton Avenue in the village of Rowayton. The bench marks are along
McKinley Avenue. The tide gage was located at Five Mile Riverworks, Inc. on the
river.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 8609 B 1995
DESIGNATION: 846 8609 B
MONUMENTATION: Tidal Station disk VM#: 13083
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Rock outcrop OPUS PID:
LATITUDE: 41° 3.9' N ( 41.06500) LONGITUDE: 73° 26.7' W ( -73.44500)
The primary bench mark is a disk set in a 4.60 m (15.1 ft) long rock outcrop in
front of house No. 12 McKinley Street, 12.41 m (40.7 ft) north of the NE corner
of the house, 8.50 m (27.9 ft) south of the centerline of McKinley Street, 6.61
m (21.7 ft) WNW of the west edge of the driveway, and 0.09 m (0.3 ft) above the
ground.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 8468609 PUBLICATION DATE: 04/21/2003
Name: ROWAYTON, FIVEMILE RIVER
CT
NOAA Chart: 12368 Latitude: 41° 3.9' N ( 41.06500)
USGS Quad: NORWALK SOUTH Longitude: 73° 26.7' W ( -73.44500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 8609 A 1995
DESIGNATION: 846 8609 A
MONUMENTATION: Tidal Station disk VM#: 13084
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete flagpole base OPUS PID:
LATITUDE: 41° 3.9' N ( 41.06500) LONGITUDE: 73° 26.7' W ( -73.44500)
The bench mark is a disk set in the concrete base of a flagpole at the Fairfield
County Savings Bank at the intersection of Rowayton Avenue and McKinley Street,
15.51 m (50.9 ft) north of the north corner of the bank, 11.0 m (36.1 ft) SSW of
the centerline of McKinley Street, 10.09 m (33.1 ft) SE of the centerline of
Rowayton Avenue, and 0.30 m (1.0 ft) SSW of the flagpole.
BENCH MARK STAMPING: 8609 C 1995
DESIGNATION: 846 8609 C
MONUMENTATION: Tidal Station disk VM#: 13085
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Rock outcrop OPUS PID:
LATITUDE: 41° 3.9' N ( 41.06500) LONGITUDE: 73° 26.7' W ( -73.44500)
The bench mark is a disk set in a rock outcrop in front of house No. 24 McKinley
Street, 14.30 m (46.9 ft) SSW of the centerline of McKinley Street, 13.29 m
(43.6 ft) east of the east corner of the house, 7.32 m (24.0 ft) WNW of the
centerline of Roton Avenue, and 1 m (3 ft) above the pavement.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 8468609 PUBLICATION DATE: 04/21/2003
Name: ROWAYTON, FIVEMILE RIVER
CT
NOAA Chart: 12368 Latitude: 41° 3.9' N ( 41.06500)
USGS Quad: NORWALK SOUTH Longitude: 73° 26.7' W ( -73.44500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 8609 D 1995
DESIGNATION: 846 8609 D
MONUMENTATION: Tidal Station disk VM#: 13086
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Rock outcrop OPUS PID:
LATITUDE: 41° 3.9' N ( 41.06500) LONGITUDE: 73° 26.7' W ( -73.44500)
The bench mark is a disk set in the NE corner of a rock outcrop on the north
side of the Jennie Kendrick House at 1890 Roton Avenue just north of McKinley
Street, 20.39 m (66.9 ft) NW of the centerline of Roton Avenue, 16.31 m (53.5
ft) east of the NW corner of the house, 12.31 m (40.4 ft) north of the NE corner
of the house, and 2 m (7 ft) above the driveway.
BENCH MARK STAMPING: 457
DESIGNATION: 846 8609 TIDAL 457
MONUMENTATION: Survey disk VM#: 13087
AGENCY: Connecticut Geodetic Survey (CTGS) IDB PID#:
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 41° 3.9' N ( 41.06500) LONGITUDE: 73° 26.7' W ( -73.44500)
The bench mark is a disk set in a concrete monument near the intersection of
McKinley Street and Highland Avenue, 12 m (39 ft) ESE of the centerline
intersection of the two streets, 4.30 m (14.1 ft) north of SNET power pole No.
4901, and 1.10 m (3.6 ft) west of a low stone masonry retaining wall.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 8468609 PUBLICATION DATE: 04/21/2003
Name: ROWAYTON, FIVEMILE RIVER
CT
NOAA Chart: 12368 Latitude: 41° 3.9' N ( 41.06500)
USGS Quad: NORWALK SOUTH Longitude: 73° 26.7' W ( -73.44500)
T I D A L D A T U M S
Tidal datums at ROWAYTON, FIVEMILE RIVER based on:
LENGTH OF SERIES: 3 Months
TIME PERIOD: June 1995 - August 1995
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 = 2.345
MEAN HIGH WATER MHW = 2.240
MEAN SEA LEVEL MSL = 1.164
MEAN TIDE LEVEL MTL = 1.159
MEAN LOW WATER MLW = 0.078
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
8609 B 1995 4.779 2.539
8609 A 1995 3.785 1.545
8609 C 1995 4.827 2.587
8609 D 1995 7.302 5.062
457 11.749 9.509
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 8468609 PUBLICATION DATE: 04/21/2003
Name: ROWAYTON, FIVEMILE RIVER
CT
NOAA Chart: 12368 Latitude: 41° 3.9' N ( 41.06500)
USGS Quad: NORWALK SOUTH Longitude: 73° 26.7' W ( -73.44500)
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.