U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 8463348 PUBLICATION DATE: 05/16/2003
Name: TYLERVILLE, CONNECTICUT R.
CT
NOAA Chart: 12377 Latitude: 41° 27.1' N ( 41.45170)
USGS Quad: DEEP RIVER Longitude: 72° 27.9' W ( -72.46500)
To reach the tidal bench marks from the north intersection of State Roads 82 and
154, go east on State Road 82 (Bridge Street) for 0.89 km (0.55 mi), turn right
into the entrance to Marine Park which is just before the swing bridge on the
Connecticut River between Tylerville and East Haddam. The bench marks are along
State Road 82 and also near the intersection of State Roads 154 and 82. The
tide gage and staff were on the northernmost dock of New England Steamship Lines
which is within the Marine Park area.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 3348 C 1987
DESIGNATION: 846 3348 C
MONUMENTATION: Tidal Station disk VM#: 2238
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Bridge abutment OPUS PID:
LATITUDE: 41° 27.0' N ( 41.45000) LONGITUDE: 72° 27.9' W ( -72.46500)
The primary bench mark is a disk set on the SW abutment of the State Road 82
swing bridge on the Connecticut River, 1.1 km (0.7 mi) east of the north
intersection of State Roads 82 and 154, 4.02 m (13.2 ft) south of the centerline
of State Road 82, and 0.15 m ( 0.5 ft) south of a steel guardrail.
BENCH MARK STAMPING: 101 W 1923
DESIGNATION: 101 W
MONUMENTATION: Survey disk VM#: 2237
AGENCY: US Geological Survey (USGS) IDB PID#: LX0203
SETTING CLASSIFICATION: Boulder OPUS PID:
LATITUDE: 41° 26.9' N ( 41.44830) LONGITUDE: 72° 28.5' W ( -72.47500)
The bench mark is a disk set in a boulder halfway up the slope between the
roadway shoulder and the base of a stone wall on State Road 154 near State Road
82, 23 m (75 ft) NNW of the northern intersection of State Roads 82 and 154, 13
m (43 ft) west of the centerline of State Road 154, 11 m (35 ft) north of power
pole #63, and 1.37 m (4.5 ft) east of a loose stone wall. Note: The mark is
not level so the high side was used to obtain elevations.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 8463348 PUBLICATION DATE: 05/16/2003
Name: TYLERVILLE, CONNECTICUT R.
CT
NOAA Chart: 12377 Latitude: 41° 27.1' N ( 41.45170)
USGS Quad: DEEP RIVER Longitude: 72° 27.9' W ( -72.46500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 3348 D 1987
DESIGNATION: 846 3348 D
MONUMENTATION: Tidal Station disk VM#: 2239
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Culvert retaining wall OPUS PID:
LATITUDE: 41° 27.0' N ( 41.45000) LONGITUDE: 72° 27.9' W ( -72.46500)
The bench mark is a disk set flush in the angle point of a L shaped concrete
retaining wall on the south side of State Road 82, 11 m (35 ft) east of the
centerline of the entrance road to Marine Park, 1.52 m (5.0 ft) south of a steel
guardrail parallel to the south side of a private driveway, which is parallel to
State Road 82, and 2.13 m (7.0 ft) below the road.
BENCH MARK STAMPING: 3348 E 1987
DESIGNATION: 846 3348 E
MONUMENTATION: Tidal Station disk VM#: 2240
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete stairway OPUS PID:
LATITUDE: 41° 27.0' N ( 41.45000) LONGITUDE: 72° 27.9' W ( -72.46500)
The bench mark is a disk set flush in the SE corner of a concrete stairway
leading from Bridge Street (State Road 82) to the yard of the residence at 71
Bridge Street, 25.76 m (84.5 ft) WSW of community fire warning support pole
#2123, 6 m (19 ft) south of the centerline of Bridge Street, 5.55 m (18.2 ft)
north of the NE corner of the residence, and at ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 8463348 PUBLICATION DATE: 05/16/2003
Name: TYLERVILLE, CONNECTICUT R.
CT
NOAA Chart: 12377 Latitude: 41° 27.1' N ( 41.45170)
USGS Quad: DEEP RIVER Longitude: 72° 27.9' W ( -72.46500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 220 X
DESIGNATION: 846 3348 220 X
MONUMENTATION: Survey disk VM#: 2241
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 41° 27.0' N ( 41.45000) LONGITUDE: 72° 27.9' W ( -72.46500)
The bench mark is a disk set in a concrete monument beside a line of trees along
State Road 82, 0.56 km (0.35 mi) east of the north intersection of State Roads
82 and 154, 8 m (26 ft) south of the centerline of State Road 82, 1.31 m (4.3
ft) west of CL&P pole #9, 0.46 m (1.5 ft) south of a steel mailbox post on State
Road 82, and at ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 8463348 PUBLICATION DATE: 05/16/2003
Name: TYLERVILLE, CONNECTICUT R.
CT
NOAA Chart: 12377 Latitude: 41° 27.1' N ( 41.45170)
USGS Quad: DEEP RIVER Longitude: 72° 27.9' W ( -72.46500)
T I D A L D A T U M S
Tidal datums at TYLERVILLE, CONNECTICUT R. based on:
LENGTH OF SERIES: 4 MONTHS
TIME PERIOD: June 1987 - September 1987
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 = 0.931
MEAN HIGH WATER MHW = 0.856
MEAN TIDE LEVEL MTL = 0.444
MEAN SEA LEVEL MSL = 0.443
MEAN LOW WATER MLW = 0.031
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
3348 C 1987 8.700 7.844
101 W 1923 16.257 15.401
3348 D 1987 5.192 4.336
3348 E 1987 24.044 23.188
220 X 24.880 24.024
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 8463348 PUBLICATION DATE: 05/16/2003
Name: TYLERVILLE, CONNECTICUT R.
CT
NOAA Chart: 12377 Latitude: 41° 27.1' N ( 41.45170)
USGS Quad: DEEP RIVER Longitude: 72° 27.9' W ( -72.46500)
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.