U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 4
PUBLICATION DATE: 06/13/1988
Station ID: 8447531 SUPERCEDED DATE: 04/21/2003
Name: MATTAPOISETT HARBOR, BUZZARDS BAY
MASSACHUSETTS
NOAA Chart: 13230 Latitude: 41° 39.4' N
USGS Quad: MARION Longitude: 70° 48.8' W
To reach the tidal bench marks from the Public School at the corner of Church
and Barstow Streets in Mattapoisett, proceed south on Barstow Street to Main or
Water Street, then west on Main or Water Street to Shipyard Park. The bench
marks are located in the area between Church Street and the park. The tide gage
and staff were located on the south end of Mattapoisett Town Wharf.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: NO 5 1931
MONUMENTATION: Survey Disk VM#: 2052
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Base
The bench mark is set in the east side of the concrete base of mizzen mast from
whaling bark WANDERER in the Shipyard Park, 0.8 foot (0.2 m) east of the mast,
0.8 foot (0.2 m) west of the foundation edge and level with the ground.
BENCH MARK STAMPING: NO 6 1931
MONUMENTATION: Survey Disk VM#: 2053
AGENCY: PID:
SETTING CLASSIFICATION: Granite Step
The bench mark is set in the east side of the second granite step from the
bottom of the main (south) entrance to Mattapoisett School at the intersection
of Church and Barstow Streets, 30 feet (9 m) west of the SE corner, 0.8 foot
(0.2 m) north of the south edge of the step, 0.2 foot (0.1 m) west of the
granite foundation, and 0.8 foot (0.2 m) above the level of the sidewalk.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 4
PUBLICATION DATE: 06/13/1988
Station ID: 8447531 SUPERCEDED DATE: 04/21/2003
Name: MATTAPOISETT HARBOR, BUZZARDS BAY
MASSACHUSETTS
NOAA Chart: 13230 Latitude: 41° 39.4' N
USGS Quad: MARION Longitude: 70° 48.8' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 7 1935
MONUMENTATION: Survey Disk VM#: 2054
AGENCY: PID:
SETTING CLASSIFICATION: Stone Wall
The bench mark is set in the top of a stone wall on the east side of the town
wharf, 25 feet (8 m) south of the NW corner of the basin east of the town wharf,
and 1 foot (0.3 m) west of the east edge of the wharf.
BENCH MARK STAMPING: NO 8 1935
MONUMENTATION: Survey Disk VM#: 2055
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Wall
The bench mark is set in the top of the lower wall on the south side of parking
space at the NE corner of the basin west of the town wharf, 32 feet (10 m) west
of Bench Mark NO 7 1935, 1.5 feet (0.5 m) north of the edge of the lower top of
the stone abutment, and 1 foot (0.3 m) below the level of the road.
BENCH MARK STAMPING: 7531 E 1976
MONUMENTATION: Survey Disk VM#: 2056
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Step
The bench mark is set flush in the lower left step leading to the entrance to
the public library on Barstow Street, and 0.5 foot (0.2 m) above ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 4
PUBLICATION DATE: 06/13/1988
Station ID: 8447531 SUPERCEDED DATE: 04/21/2003
Name: MATTAPOISETT HARBOR, BUZZARDS BAY
MASSACHUSETTS
NOAA Chart: 13230 Latitude: 41° 39.4' N
USGS Quad: MARION Longitude: 70° 48.8' W
T I D A L D A T U M S
Tidal datums at MATTAPOISETT HARBOR, BUZZARDS BAY based on:
LENGTH OF SERIES: 4 MONTHS
TIME PERIOD: JUNE - OCTOBER 1976
TIDAL EPOCH: 1960-1978
CONTROL TIDE STATION: 8452660 NEWPORT, RI
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET:
HIGHEST OBSERVED WATER LEVEL (10/21/1976) = 6.72
MEAN HIGHER HIGH WATER MHHW = 4.27
MEAN HIGH WATER MHW = 4.00
MEAN TIDE LEVEL MTL = 2.07
MEAN LOW WATER MLW = 0.14
MEAN LOWER LOW WATER MLLW = 0.00
LOWEST OBSERVED WATER LEVEL (09/15/1976) = -1.71
Bench Mark Elevation Information In FEET above:
Stamping or Designation MLLW MHW
NO 5 1931 13.25 9.25
NO 6 1931 20.53 16.53
NO 7 1935 7.32 3.32
NO 8 1935 6.08 2.08
7531 E 1976 18.68 14.68
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 4
PUBLICATION DATE: 06/13/1988
Station ID: 8447531 SUPERCEDED DATE: 04/21/2003
Name: MATTAPOISETT HARBOR, BUZZARDS BAY
MASSACHUSETTS
NOAA Chart: 13230 Latitude: 41° 39.4' N
USGS Quad: MARION Longitude: 70° 48.8' 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 (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 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.