U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 6
Station ID: 8461490 PUBLICATION DATE: 04/21/2003
Name: NEW LONDON, THAMES RIVER
CT
NOAA Chart: 13213 Latitude: 41° 21.3' N ( 41.35500)
USGS Quad: NEW LONDON Longitude: 72° 5.2' W ( -72.08670)
To reach the tidal bench marks from Interstate 95 south bound, take exit 84E to
Williams Street. Continue on Williams Street 0.5 km (0.3 mi) to State Pier
Road. Turn left and follow the road for 1.1 km (0.7 mi). Take first right over
railroad tracks onto road leading to State Pier. Proceed for 0.3 km (0.2 mi) to
its end. Turn right into gate to the Port of New London Terminal. The bench
marks are located within 1.6 km (1 mi) radius of the tide station. The tide
station is at the south end of the pier, behind the State Pier warehouse.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 15 1947
DESIGNATION: 846 1490 TIDAL 15
MONUMENTATION: Tidal Station disk VM#: 239
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: LX0157
SETTING CLASSIFICATION: Retaining wall OPUS PID:
LATITUDE: 41° 21.6' N ( 41.36028) LONGITUDE: 72° 5.5' W ( -72.09169)
The primary bench mark is a disk set on the concrete retaining wall along the
west side of the ramp leading to the Connecticut State Pier from Winthrop
Street, 225.9 m (741 ft) south along the ramp from Winthrop Street, 6.86 m (22.5
ft) north of the south end of the retaining wall, 4.27 m (14.0 ft) west of the
center line of ramp, and 0.15 m (0.5 ft) above the ramp.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 6
Station ID: 8461490 PUBLICATION DATE: 04/21/2003
Name: NEW LONDON, THAMES RIVER
CT
NOAA Chart: 13213 Latitude: 41° 21.3' N ( 41.35500)
USGS Quad: NEW LONDON Longitude: 72° 5.2' W ( -72.08670)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1490 K 1979
DESIGNATION: 846 1490 K TIDAL
MONUMENTATION: Tidal Station disk VM#: 242
AGENCY: National Ocean Survey (NOS) IDB PID#: LX3418
SETTING CLASSIFICATION: Bedrock OPUS PID#: LX3418
LATITUDE: 41° 21.7' N ( 41.36169) LONGITUDE: 72° 5.7' W ( -72.09472)
The bench mark is a disk set in bedrock, located 0.2 km (0.1 mi) west along
State Pier Road from the junction of Winthrop Street, 46.94 m (154.0 ft) NW of
the NW bridge abutment of the westernmost steel span over railroad tracks, 10.39
m (34.1 ft) NNW of the centerline of State Pier Road, 6.43 m (21.1 ft) SSE of
the south rail of the southernmost tracks, and 0.30 m (0.98 ft) above ground.
BENCH MARK STAMPING: 1490 M 1990
DESIGNATION: 846 1490 M
MONUMENTATION: Tidal Station disk VM#: 247
AGENCY: National Ocean Service (NOS) IDB PID#: AI1720
SETTING CLASSIFICATION: Concrete foundation OPUS PID:
LATITUDE: 41° 21.4' N ( 41.35669) LONGITUDE: 72° 5.7' W ( -72.09500)
The bench mark is a disk set in the concrete foundation at the NW corner of the
Ferry Repair Building, 30.48 m (100.0 ft) NNW of the SW corner of the Ferry
Repair Building, 17.68 m (58.0 ft) NE of a railroad signal, 2.90 m (9.5 ft) SE
of Power Pole number 625, and 0.6 m (0.2 ft) above the sidewalk.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 6
Station ID: 8461490 PUBLICATION DATE: 04/21/2003
Name: NEW LONDON, THAMES RIVER
CT
NOAA Chart: 13213 Latitude: 41° 21.3' N ( 41.35500)
USGS Quad: NEW LONDON Longitude: 72° 5.2' W ( -72.08670)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1490 N 1995
DESIGNATION: 846 1490 N
MONUMENTATION: Tidal Station disk VM#: 13807
AGENCY: National Ocean Service (NOS) IDB PID#: AI1721
SETTING CLASSIFICATION: Concrete apron OPUS PID:
LATITUDE: 41° 21.7' N ( 41.36169) LONGITUDE: 72° 5.4' W ( -72.09000)
The bench mark is a disk set in the concrete apron, located in the parking area
on the State of Connecticut Bureau of Aviation and Ports property, 20.70 m (67.9
ft) SW of the NE corner of the bulkhead, 18.60 m (61.0 ft) east of Light Pole
number 13, and 1.60 m (5.2 ft) south of the north face of the bulkhead.
BENCH MARK STAMPING: 1490 P 1995
DESIGNATION: 846 1490 P
MONUMENTATION: Tidal Station disk VM#: 13808
AGENCY: National Ocean Service (NOS) IDB PID#: AI1722
SETTING CLASSIFICATION: Concrete foundation OPUS PID:
LATITUDE: 41° 21.6' N ( 41.36061) LONGITUDE: 72° 5.5' W ( -72.09097)
The bench mark is a disk set in the concrete foundation, located In the parking
area on the State of Connecticut Bureau of Aviation and Ports property, 43.89 m
(144.0 ft) SSW of Light Pole number 14, 5.21 m (17.1 ft) east of the west corner
of the Aviation and Ports Building, and 0.30 m (1.0 ft) west of the east side of
the garage door frame.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 6
Station ID: 8461490 PUBLICATION DATE: 04/21/2003
Name: NEW LONDON, THAMES RIVER
CT
NOAA Chart: 13213 Latitude: 41° 21.3' N ( 41.35500)
USGS Quad: NEW LONDON Longitude: 72° 5.2' W ( -72.08670)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1490 B 1998
DESIGNATION: 846 1490 B
MONUMENTATION: Flange-encased Rod VM#: 15484
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod in sleeve OPUS PID#: BBDJ16
LATITUDE: 41° 21.7' N ( 41.36217) LONGITUDE: 72° 5.4' W ( -72.08975)
The bench mark is located along the south side of the entrance road at the NE
corner of the Bureau of Aviation and Ports property, 11.93 m (39.1 ft) SW of the
center of a gate in a chain link fence, 11.65 m (38.2 ft) north of the SE corner
of a 2 door garage, 8.35 m (27.4 ft) NE of the NE corner of the garage, 2.11 m
(6.9 ft) north of the last of four light poles in a row, and 0.95 m (3.1 ft)
north of a NOAA witness post. The datum point is set an undetermined distance
below ground, being the top of a stainless steel rod driven 20.42 m (67.0 ft) to
refusal, and encased in a 5 inch NOS logo cap.
BENCH MARK STAMPING: 1490 C 2001
DESIGNATION: 846 1490 C
MONUMENTATION: Tidal Station disk VM#: 16533
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete bridge abutment OPUS PID:
LATITUDE: 41° 21.7' N ( 41.36200) LONGITUDE: 72° 5.5' W ( -72.09200)
The bench is a disk set in a concrete bridge abutment on the east side of the
bridge in the parapet wall, 32.9 m (107.9 ft), south of the intersection of
State Pier Road and Winthrop Street, 18.6 m (61.0 ft) north of the south end of
a metal guardrail, and 5.4 m (17.7 ft) east of the centerline of Winthrop Sreet.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 6
Station ID: 8461490 PUBLICATION DATE: 04/21/2003
Name: NEW LONDON, THAMES RIVER
CT
NOAA Chart: 13213 Latitude: 41° 21.3' N ( 41.35500)
USGS Quad: NEW LONDON Longitude: 72° 5.2' W ( -72.08670)
T I D A L D A T U M S
Tidal datums at NEW LONDON, THAMES RIVER based on:
LENGTH OF SERIES: 19 Years
TIME PERIOD: January 1983 - December 2001
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION:
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
HIGHEST OBSERVED WATER LEVEL (09/21/1938) = 3.224
MEAN HIGHER HIGH WATER MHHW = 0.930
MEAN HIGH WATER MHW = 0.840
North American Vertical Datum NAVD88 = 0.560
MEAN SEA LEVEL MSL = 0.468
MEAN TIDE LEVEL MTL = 0.449
MEAN LOW WATER MLW = 0.059
MEAN LOWER LOW WATER MLLW = 0.000
LOWEST OBSERVED WATER LEVEL (02/02/1976) = -1.220
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
15 1947 3.806 2.966
1490 K 1979 9.398 8.558
1490 M 1990 2.476 1.636
1490 N 1995 2.910 2.071
1490 P 1995 3.923 3.083
1490 B 1998 3.958 3.118
1490 C 2001 9.933 9.093
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 6
Station ID: 8461490 PUBLICATION DATE: 04/21/2003
Name: NEW LONDON, THAMES RIVER
CT
NOAA Chart: 13213 Latitude: 41° 21.3' N ( 41.35500)
USGS Quad: NEW LONDON Longitude: 72° 5.2' W ( -72.08670)
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.