U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 8464418 PUBLICATION DATE: 02/05/2004
Name: SOUTH HARTFORD, CONNECTICUT RIVER
CT
NOAA Chart: 12377 Latitude: 41° 45.3' N ( 41.75500)
USGS Quad: HARTFORD NORTH Longitude: 72° 39.5' W ( -72.65830)
To reach the tidal bench marks from northbound Interstate Highway 91 south of
Hartford, take exit #29 for Brainard Road, turn left (west) on Brainard Road and
go 0.7 mile (1.1 km), then bear left (south) on Reserve Road and go 0.6 mile
(1.0 km), then turn right (west) on a paved road and continue over the top of
the berm and under Charter Oak Bridge for 0.2 mile (0.3 km) to Charter Oak
Landing. The bench marks are near the landing, along Reserve Road, and a few
blocks NW of Interstate Highway 95. The tide gage and staff were near the SE
end of the walkway leading to the lower landing for the tour boat.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 4418 A 1988
DESIGNATION: 846 4418 A
MONUMENTATION: Tidal Station disk VM#: 4819
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete base OPUS PID:
LATITUDE: 41° 45.3' N ( 41.75500) LONGITUDE: 72° 39.5' W ( -72.65830)
The primary bench mark is a disk set flush in the NE corner of the concrete base
for a bollard, 34 m (112 ft) east of the centerline of the paved road leading to
Charter Oak Landing tour boat dock, 27.86 m (91.4 ft) south of the SW corner of
the handrail on the south side of the landing, 4.88 m (16.0 ft) west of the
riverbank, and 0.2 m (0.7 ft) above ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 8464418 PUBLICATION DATE: 02/05/2004
Name: SOUTH HARTFORD, CONNECTICUT RIVER
CT
NOAA Chart: 12377 Latitude: 41° 45.3' N ( 41.75500)
USGS Quad: HARTFORD NORTH Longitude: 72° 39.5' W ( -72.65830)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 4418 B 1988
DESIGNATION: 846 4418 B
MONUMENTATION: Tidal Station disk VM#: 4820
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete footing OPUS PID:
LATITUDE: 41° 45.3' N ( 41.75500) LONGITUDE: 72° 39.5' W ( -72.65830)
The bench mark is a disk set flush in the concrete footing of the westernmost of
two concrete piers supporting Interstate Highway 95, 12.28 m (40.3 ft) west of
the SW corner of the easternmost pier, 11.89 m (39.0 ft) north of the centerline
of Reserve Road, 0.7 m (2.4 ft) east of the west edge of the footing, and 0.6 m
(2.0 ft) above ground level.
BENCH MARK STAMPING: 4418 C 1988
DESIGNATION: 846 4418 C
MONUMENTATION: Tidal Station disk VM#: 4821
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete platform OPUS PID:
LATITUDE: 41° 45.3' N ( 41.75500) LONGITUDE: 72° 39.5' W ( -72.65830)
The bench mark is a disk set flush in a concrete platform at the intersection of
Reserve Road and Wawarme Avenue, SW of the railroad tracks, 20.85 m (68.4 ft)
SSW of CL&P power pole #8550, 8.96 m (29.4 ft) SE of the centerline of Reserve
Road, 7.71 m (25.3 ft) SSW of the SW wall of southbound I-91, and 0.2 m (0.6 ft)
above ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 8464418 PUBLICATION DATE: 02/05/2004
Name: SOUTH HARTFORD, CONNECTICUT RIVER
CT
NOAA Chart: 12377 Latitude: 41° 45.3' N ( 41.75500)
USGS Quad: HARTFORD NORTH Longitude: 72° 39.5' W ( -72.65830)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING:
DESIGNATION: 846 4418 NO STAMPING 1
MONUMENTATION: Nail VM#: 4822
AGENCY: City of Hartford IDB PID#:
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 41° 45.3' N ( 41.75500) LONGITUDE: 72° 39.5' W ( -72.65830)
The bench mark is a nail set in the top of a concrete monument with a metal cap,
0.2 km (0.1 mi) south of bench mark 4410 B 1988, 13.11 m (43.0 ft) SSW of the
center of a blue fire hydrant, 12.95 m (42.5 ft) east of the centerline of
Reserve Road, 1.95 m (6.4 ft) west of a 2 m (7 ft) high chain link fence, and at
ground level.
BENCH MARK STAMPING:
DESIGNATION: 846 4418 NO STAMPING 2
MONUMENTATION: Nail VM#: 4823
AGENCY: City of Hartford IDB PID#:
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 41° 45.3' N ( 41.75500) LONGITUDE: 72° 39.5' W ( -72.65830)
The bench mark is a nail set in the top of a concrete monument with a metal cap,
at the intersection of Weehasset Street and Van Block Avenue, 10.76 m (35.3 ft)
south of the SW corner of a brick housing unit, 8.23 m (27.0 ft) NNW of the
centerline of Weehasset Street, 6.28 m (20.6 ft) ENE of the centerline of Van
Block Avenue, 1.46 m (4.8 ft) east of an unnumbered power pole, and 0.03 m (0.1
ft) below sidewalk level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 8464418 PUBLICATION DATE: 02/05/2004
Name: SOUTH HARTFORD, CONNECTICUT RIVER
CT
NOAA Chart: 12377 Latitude: 41° 45.3' N ( 41.75500)
USGS Quad: HARTFORD NORTH Longitude: 72° 39.5' W ( -72.65830)
T I D A L D A T U M S
Tidal datums at SOUTH HARTFORD, CONNECTICUT RIVER based on:
LENGTH OF SERIES: 4 MONTHS
TIME PERIOD: June 1988 - September 1988
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 = 0.699
MEAN HIGH WATER MHW = 0.621
MEAN SEA LEVEL MSL = 0.354
MEAN TIDE LEVEL MTL = 0.327
MEAN LOW WATER MLW = 0.032
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
4418 A 1988 3.845 3.224
4418 B 1988 9.401 8.780
4418 C 1988 9.151 8.530
846 4418 NO STAMPING 1 4.863 4.242
846 4418 NO STAMPING 2 5.027 4.406
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 8464418 PUBLICATION DATE: 02/05/2004
Name: SOUTH HARTFORD, CONNECTICUT RIVER
CT
NOAA Chart: 12377 Latitude: 41° 45.3' N ( 41.75500)
USGS Quad: HARTFORD NORTH Longitude: 72° 39.5' W ( -72.65830)
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.