U.S. DEPARTMENT OF COMMERCE
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National Ocean Service
Datums Page Page 1 of 7
Station ID: 8461467 PUBLICATION DATE: 07/12/2004
Name: YALE BOATHOUSE, THAMES RIVER
CT
NOAA Chart: 12372 Latitude: 41° 25.8' N ( 41.43000)
USGS Quad: UNCASVILLE Longitude: 72° 5.6' W ( -72.09330)
To reach the tidal bench marks from the Post Office in Gales Ferry, proceed
south on Military Highway for 0.2 km (0.1 mi) to Hurlbutt Road, then west on
Hurlbutt Road for 1.1 km (0.7 mi) to its end at Yale Boathouse on the Thames
River. The tidal bench marks are along Hurlbutt Road and on the Yale Boathouse
property. The tide gage and staff were on the small two piling pier.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 1467 A 1989
DESIGNATION: 846 1467 A 1989
MONUMENTATION: Survey disk VM#: 4814
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete foundation OPUS PID:
LATITUDE: 41° 25.8' N ( 41.43000) LONGITUDE: 72° 5.6' W ( -72.09330)
The primary bench mark is a disk set in the SW corner of a 1 m x 1 m (3 ft x 3
ft) square concrete storm drain foundation, 43 m (141 ft) NNE of the NW corner
of Yale Boathouse, 10.18 m (33.4 ft) south of the centerline of Hurlbutt Road,
7.28 m (23.9 ft) north of the NW corner of the bottom granite step leading down
from Yale Crewhouse, and 0.3 m (1 ft) above grade.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 7
Station ID: 8461467 PUBLICATION DATE: 07/12/2004
Name: YALE BOATHOUSE, THAMES RIVER
CT
NOAA Chart: 12372 Latitude: 41° 25.8' N ( 41.43000)
USGS Quad: UNCASVILLE Longitude: 72° 5.6' W ( -72.09330)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 45 127 W 1923
DESIGNATION: 846 1467 45 127 W 1923
MONUMENTATION: Survey disk VM#: 4810
AGENCY: US Geological Survey (USGS) IDB PID#:
SETTING CLASSIFICATION: Bedrock OPUS PID:
LATITUDE: 41° 25.8' N ( 41.43000) LONGITUDE: 72° 5.6' W ( -72.09330)
The bench mark is a disk set in a small bedrock outcrop on the east side of
Military Highway just north of its intersection with Hurlbutt Road, 38 m (125
ft) NE of the centerline of Hurlbutt Road, 26.94 m (88.4 ft) south of CL&P power
pole #919, 9.11 m (29.9 ft) west of the north corner of the building on the NE
corner of the intersection, and 7.38 m (24.2 ft) from the centerline of Military
Highway.
BENCH MARK STAMPING: RED TOP 2 1934
DESIGNATION: 846 1467 RED TOP 2 1934
MONUMENTATION: Survey disk VM#: 4811
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: LX5095
SETTING CLASSIFICATION: Bedrock OPUS PID:
LATITUDE: 41° 25.2' N ( 41.42000) LONGITUDE: 72° 5.3' W ( -72.08830)
The bench mark is a disk set in a bedrock ledge, 52 m (170 ft) north along the
railroad tracks from the crossing of the Harvard Boathouse access road, 8 m (26
ft) east of the centerline of the tracks, and 5 m (17 ft) above track level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 7
Station ID: 8461467 PUBLICATION DATE: 07/12/2004
Name: YALE BOATHOUSE, THAMES RIVER
CT
NOAA Chart: 12372 Latitude: 41° 25.8' N ( 41.43000)
USGS Quad: UNCASVILLE Longitude: 72° 5.6' W ( -72.09330)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: RED TOP 2 NO 1 1934
DESIGNATION: 846 1467 RED TOP 2 NO 1
MONUMENTATION: Survey disk VM#: 4812
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: AE4774
SETTING CLASSIFICATION: Bedrock OPUS PID:
LATITUDE: 41° 25.8' N ( 41.43000) LONGITUDE: 72° 5.6' W ( -72.09330)
The bench mark is a disk set in a bedrock ledge, 52 m (170 ft) north along the
railroad tracks from the crossing of the Harvard Boathouse access road, 13.90 m
(45.6 ft) NE of Bench Mark RED TOP 2 1934, and 10 m (32 ft) above track level.
BENCH MARK STAMPING: RED TOP 2 NO 2 1934
DESIGNATION: 846 1467 RED TOP 2 NO 2
MONUMENTATION: Survey disk VM#: 4813
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: AE4775
SETTING CLASSIFICATION: Bedrock lege OPUS PID:
LATITUDE: 41° 25.8' N ( 41.43000) LONGITUDE: 72° 5.6' W ( -72.09330)
The bench mark is a disk set in a bedrock ledge, 52 m (170 ft) north along the
railroad tracks from the crossing of the Harvard Boathouse access road, 15.06 m
(49.4 ft) north of Bench Mark RED TOP 2 NO 1 1934, and 10 m (32 ft) above track
level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 7
Station ID: 8461467 PUBLICATION DATE: 07/12/2004
Name: YALE BOATHOUSE, THAMES RIVER
CT
NOAA Chart: 12372 Latitude: 41° 25.8' N ( 41.43000)
USGS Quad: UNCASVILLE Longitude: 72° 5.6' W ( -72.09330)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1467 B 1989
DESIGNATION: 846 1467 B 1989
MONUMENTATION: Survey disk VM#: 4815
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete foundation OPUS PID#: BBDC91
LATITUDE: 41° 25.8' N ( 41.43000) LONGITUDE: 72° 5.6' W ( -72.09330)
The bench mark is a disk set in a 1.4 m x 2.3 m (4.5 ft x 7.5 ft) concrete storm
drain foundation, 14.33 m (47.0 ft) SSE of the SE corner of the Yale Crewhouse,
10.45 m (34.3 ft) west of the centerline of Riverside Place, and 7.53 m (24.7
ft) NW of CL&P power pole #46.
BENCH MARK STAMPING: 1467 C 1989
DESIGNATION: 846 1467 C 1989
MONUMENTATION: Survey disk VM#: 4816
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete bridge abutment OPUS PID:
LATITUDE: 41° 25.8' N ( 41.43000) LONGITUDE: 72° 5.6' W ( -72.09330)
The bench mark is a disk set in the SW corner bridge abutment of the Hurlbutt
Road railroad overpass, 19.45 m (63.8 ft) east of CL&P power pole #2538, 6.10 m
(20.0 ft) south of the centerline of Hurlbutt Road, 1.13 m (3.7 ft) east of the
SW corner of the abutment, and 0.76 m (2.5 ft) below the top of the concrete
bridge siderail.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 7
Station ID: 8461467 PUBLICATION DATE: 07/12/2004
Name: YALE BOATHOUSE, THAMES RIVER
CT
NOAA Chart: 12372 Latitude: 41° 25.8' N ( 41.43000)
USGS Quad: UNCASVILLE Longitude: 72° 5.6' W ( -72.09330)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1467 D 1989
DESIGNATION: 846 1467 D 1989
MONUMENTATION: Survey disk VM#: 4817
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete foundation OPUS PID:
LATITUDE: 41° 25.8' N ( 41.43000) LONGITUDE: 72° 5.6' W ( -72.09330)
The bench mark is a disk set in the top NW corner of the 2 m x 2 m (5 ft x 7 ft)
concrete rear entrance to Gales Ferry Community Center on Hurlbutt Road, 12.01 m
(39.4 ft) NNW of the NE corner of the community center, 9.72 m (31.9 ft) SSE of
the NE corner of Gales Ferry Library, 5.58 m (18.3 ft) SSW of a 2.44 m (8.0 ft)
tall chain link fence, 1.13 m (3.7 ft) NNE of the community center's rear wall,
and 0.43 m (1.4 ft) above grade.
BENCH MARK STAMPING: 1480
DESIGNATION: 846 1467 1480
MONUMENTATION: Survey disk VM#: 4818
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Bedrock OPUS PID:
LATITUDE: 41° 25.8' N ( 41.43000) LONGITUDE: 72° 5.6' W ( -72.09330)
The bench mark is a disk set in the top of a 15 m (50 ft) long granite bedrock
ridge running parallel to the west side of Mulberry Drive, 274 m (900 ft) SE of
Harvard Boathouse, 152 m (500 ft) west of Military Highway, 28 m (93 ft) west of
the NW corner of a one-story residence, 12.95 m (42.5 ft) NW of CL&P power pole
#1448, 10 m (33 ft) west of the centerline of Mulberry Drive, 9 m (30 ft) east
of the railroad tracks, and 2 m (5 ft) above road level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 7
Station ID: 8461467 PUBLICATION DATE: 07/12/2004
Name: YALE BOATHOUSE, THAMES RIVER
CT
NOAA Chart: 12372 Latitude: 41° 25.8' N ( 41.43000)
USGS Quad: UNCASVILLE Longitude: 72° 5.6' W ( -72.09330)
T I D A L D A T U M S
Tidal datums at YALE BOATHOUSE, THAMES RIVER based on:
LENGTH OF SERIES: 4 MONTHS
TIME PERIOD: July 1989 - October 1989
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8461490 NEW LONDON, THAMES RIVER
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 0.990
MEAN HIGH WATER MHW = 0.897
MEAN SEA LEVEL MSL = 0.502
MEAN TIDE LEVEL MTL = 0.480
MEAN LOW WATER MLW = 0.064
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
1467 A 1989 3.164 2.267
45 127 W 1923 13.849 12.952
RED TOP 2 1934 10.373 9.476
RED TOP 2 NO 1 1934 14.789 13.892
RED TOP 2 NO 2 1934 14.791 13.894
1467 B 1989 9.846 8.949
1467 C 1989 14.503 13.606
1467 D 1989 15.407 14.510
1480 6.745 5.848
Foot Notes:
Bench marks RED TOP 2 1934, RED TOP 2 NO 1 1934, RED TOP 2 NO 2 1934 and 1480
are based on one differential leveling connection and do not meet the quality
control standards of the NOS. Therefore, caution should be used when deriving
elevations for these marks.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 7 of 7
Station ID: 8461467 PUBLICATION DATE: 07/12/2004
Name: YALE BOATHOUSE, THAMES RIVER
CT
NOAA Chart: 12372 Latitude: 41° 25.8' N ( 41.43000)
USGS Quad: UNCASVILLE Longitude: 72° 5.6' W ( -72.09330)
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.