U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 7
Station ID: 8443970 PUBLICATION DATE: 04/21/2003
Name: BOSTON, BOSTON HARBOR
MASSACHUSETTS
NOAA Chart: 13272 Latitude: 42° 21.3' N
USGS Quad: BOSTON SOUTH Longitude: 71° 3.1' W
To reach the tidal bench marks from north bound lane of U.S. Interstate Highway
93 and the Atlantic and Northern Avenues exits in Boston, proceed to the U.S.
Coast Guard Building at the intersection of Atlantic and Northern Avenues. The
bench marks are in the vicinity of the U.S. Coast Guard Building, U.S. Custom
House, U.S. Post Office and at the intersection of Purchase and High Streets.
The tide station is located on the right side of the U.S. Coast Guard Building
adjacent to Northern Avenue Bridge.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: K 12 MASS G.S. 1936 14.292
DESIGNATION: K 12
MONUMENTATION: Tidal Station disk VM#: 185
AGENCY: US Coast and Geodetic Survey (USC&GS) PID#: MY0555
SETTING CLASSIFICATION: Granite step
The primary bench mark is a disk set in the top of the east end of the first
step at the NW (main) entrance of the U.S. Coast Guard Building at the
intersection of Atlantic and Northern Avenues, 5.79 m (19.0 ft) north of a fire
hydrant, 1.62 M (5.3 ft) NE of the center of the doorway, 2.90 m (9.5 ft) SE of
the rounded curb at the intersection, and 0.21 m (0.7 ft) SW of the SW corner of
the Coast Guard Building, and 0.3 m (1 ft) above ground.
BENCH MARK STAMPING: J 12 MASS. G.S. 1936 13.321
DESIGNATION: 844 3970 J 12
MONUMENTATION: Bench Mark disk VM#: 184
AGENCY: US Coast and Geodetic Survey (USC&GS) PID#: MY0562
SETTING CLASSIFICATION: Step
The bench mark is a disk set in the NE end of the third step of the westernmost
set of steps at the north entrance of the A. P. New England Office Building,
located at the intersection of Congress Street and Atlantic Avenue, 7.16 m (23.5
ft) SW of the SW curb of Atlantic Avenue, 6.64 m (21.8 ft) SW of the door to the
building, 3.99 m (13.1 ft) SE of the SE curb of Congress Street, 2.07 m (6.8 ft)
west of the center of the entrance, and 0.6 m (2 ft) above the sidewalk.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 7
Station ID: 8443970 PUBLICATION DATE: 04/21/2003
Name: BOSTON, BOSTON HARBOR
MASSACHUSETTS
NOAA Chart: 13272 Latitude: 42° 21.3' N
USGS Quad: BOSTON SOUTH Longitude: 71° 3.1' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 15 1950
DESIGNATION: 844 3970 TIDAL 15
MONUMENTATION: Tidal Station disk VM#: 186
AGENCY: US Coast and Geodetic Survey (USC&GS) PID#: MY0556
SETTING CLASSIFICATION: Granite foundation
The bench mark is a disk set in the top of the granite ledge around the base of
the U.S. Custom House at the intersection of India and Central Streets, 6.40 m
(21.0 ft) east of the center of the entrance to the building, 5.03 m (16.5 ft)
west of the SE corner of the building, 0.3 m (1 ft) south of the south face of
the building, and 0.3 m (1 ft) above the sidewalk.
BENCH MARK STAMPING: NO 16 1973
DESIGNATION: 844 3970 TIDAL 16
MONUMENTATION: Tidal Station disk VM#: 187
AGENCY: US Coast and Geodetic Survey (USC&GS) PID:
SETTING CLASSIFICATION: Granite bulkhead cap
The bench mark is a disk set in the top of the granite bulkhead cap located near
Northern Avenue and the U.S. Coast Guard building, 12.89 m (42.3 ft) south of
the northernmost bollard on the seawall, 9.60 m (31.5 ft) SE of the NE corner of
the building, and 0.43 m (1.4 ft) west of the west edge of the cap.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 7
Station ID: 8443970 PUBLICATION DATE: 04/21/2003
Name: BOSTON, BOSTON HARBOR
MASSACHUSETTS
NOAA Chart: 13272 Latitude: 42° 21.3' N
USGS Quad: BOSTON SOUTH Longitude: 71° 3.1' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: FED 2 ELEV 20.186
DESIGNATION: 844 3970 TIDAL 1
MONUMENTATION: Tidal Station disk VM#: 190
AGENCY: US Coast and Geodetic Survey (USC&GS) PID#: MY0557
SETTING CLASSIFICATION: Stone step
The bench mark is a disk set in the south end of the bottom step of the
Devonshire Street entrance of the U.S. Post Office which is in the business
district bounded by Devonshire, Water, Congress and Milk Streets, 7.62 m (25.0
ft) east of the centerline of Devonshire Street, and 2.19 m (7.2 ft) south of
the centerline of the steps leading to the post office.
BENCH MARK STAMPING: 3970 A 1990
DESIGNATION: 844 3970 A
MONUMENTATION: Tidal Station disk VM#: 194
AGENCY: National Ocean Service (NOS) PID:
SETTING CLASSIFICATION: Interstate overpass foundation
The bench mark is a disk set in the NE corner of the concrete foundation
supporting an overpass exit of the I-93 Expressway at the intersection of
Purchase and High Streets, 29.26 m (96.0 ft) SE of the southernmost corner of
the building at 200 High Street, 5.18 m (17.0 ft) west of the centerline of
Purchase Street, 3.66 m (12.0 ft) east of the centerline of Surface Street, and
0.21 m (0.7 ft) above the sidewalk.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 7
Station ID: 8443970 PUBLICATION DATE: 04/21/2003
Name: BOSTON, BOSTON HARBOR
MASSACHUSETTS
NOAA Chart: 13272 Latitude: 42° 21.3' N
USGS Quad: BOSTON SOUTH Longitude: 71° 3.1' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 3970 B 1990
DESIGNATION: 844 3970 B
MONUMENTATION: Tidal Station disk VM#: 195
AGENCY: National Ocean Service (NOS) PID:
SETTING CLASSIFICATION: Interstate overpass foundation
The bench mark is a disk set in the SE corner of the concrete foundation
supporting the southbound lanes of the I-93 Expressway at the intersection of
Surface and India Streets, 17.83 m (58.5 ft) east of the eastern corner of the
Custom House Building, 12.19 m (40.0 ft) west of the centerline of Surface
Street, 6.40 m (21.0 ft) south of the centerline of India Street, and 0.21 m
(0.7 ft) above the sidewalk.
BENCH MARK STAMPING: 3970 C 1991
DESIGNATION: 844 3970 C
MONUMENTATION: Tidal Station disk VM#: 13804
AGENCY: National Ocean Service (NOS) PID:
SETTING CLASSIFICATION: Granite bridge abutment
The bench mark is a disk set in the granite bridge abutment on the western side
of the Northern Avenue Swing Bridge located at the east face of the Hook Lobster
Company building, 24.63 m (80.8 ft) south of the SE corner of the U.S. Coast
Guard building, 13.81 m (45.3 ft) ESE of the NW corner of the lobster company
building, and 0.34 m (1.1 ft) WNW of the south edge of the granite bridge
abutment.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 7
Station ID: 8443970 PUBLICATION DATE: 04/21/2003
Name: BOSTON, BOSTON HARBOR
MASSACHUSETTS
NOAA Chart: 13272 Latitude: 42° 21.3' N
USGS Quad: BOSTON SOUTH Longitude: 71° 3.1' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 3970 D 2000
DESIGNATION: 844 3970 D
MONUMENTATION: Tidal Station disk VM#: 16235
AGENCY: National Geodetic Survey (NGS) PID:
SETTING CLASSIFICATION: Granite sea wall cap
The bench mark is a disk set in the granite bulkhead cap between two metal
bollards of the seawall at the Christopher Columbus Park located at the
intersection of Atlantic Avenue and Richmond Streets, 31.28 m (102.6 ft) ENE of
the east face of the Christopher Columbus Statue, and 7.50 m (24.6 ft) ENE of
the granite foundation of the third lamp post north of the south end of the
granite steps at the park entrance.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 7
Station ID: 8443970 PUBLICATION DATE: 04/21/2003
Name: BOSTON, BOSTON HARBOR
MASSACHUSETTS
NOAA Chart: 13272 Latitude: 42° 21.3' N
USGS Quad: BOSTON SOUTH Longitude: 71° 3.1' W
T I D A L D A T U M S
Tidal datums at BOSTON, BOSTON HARBOR 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 (02/07/1978) = 4.601
MEAN HIGHER HIGH WATER (MHHW) = 3.131
MEAN HIGH WATER (MHW) = 2.996
NORTH AMERICAN VERTICAL DATUM-1988 (NAVD) = 1.678
MEAN SEA LEVEL (MSL) = 1.585
MEAN TIDE LEVEL (MTL) = 1.550
MEAN LOW WATER (MLW) = 0.103
MEAN LOWER LOW WATER (MLLW) = 0.000
LOWEST OBSERVED WATER LEVEL (03/24/1940) = -1.135
National Geodetic Vertical Datum (NGVD 29)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
K 12 MASS G.S. 1936 14.292 5.784 2.787
J 12 MASS. G.S. 1936 13.321 5.472 2.476
NO 15 1950 5.059 2.063
NO 16 1973 4.946 1.950
FED 2 ELEV 20.186 7.573 4.576
3970 A 1990 6.420 3.423
3970 B 1990 4.719 1.722
3970 C 1991 6.268 3.272
3970 D 2000 4.248 1.252
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 7 of 7
Station ID: 8443970 PUBLICATION DATE: 04/21/2003
Name: BOSTON, BOSTON HARBOR
MASSACHUSETTS
NOAA Chart: 13272 Latitude: 42° 21.3' N
USGS Quad: BOSTON SOUTH Longitude: 71° 3.1' W
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 (NAVD 88).
NGVD 29 is a fixed datum adopted as a national standard geodetic reference for
heights but is now considered superseded. NGVD 29 is sometimes referred to as
Sea Level Datum of 1929 or as Mean Sea Level on some early issues of Geological
Survey Topographic Quads. NGVD 29 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 NGVD 29 are available from the National
Geodetic Survey (NGS) data base via the World Wide Web at
National Geodetic Survey.
NAVD 88 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. NAVD 88 replaces NGVD 29 as the national
standard geodetic reference for heights. Bench mark elevations relative to
NAVD 88 are available from NGS through the World Wide Web at
National Geodetic Survey.
NGVD 29 and NAVD 88 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 NAVD 88 elevation is shown on the Elevations of Tidal Datums Table Referred
to MLLW only when two or more of the bench marks listed have NAVD 88 elevations.
The NAVD 88 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, NAVD 88 bench mark elevations computed indirectly from the tidal
datums elevation table may differ slightly from NAVD 88 elevations listed for
each bench mark in the NGS database.