U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 8447277 PUBLICATION DATE: 06/28/2004
Name: ONSET BEACH T-12
MASSACHUSETTS
NOAA Chart: 13246 Latitude: 41° 44.5' N
USGS Quad: ONSET Longitude: 70° 39.5' W
To reach the tidal bench marks from the intersection of U.S. Highway 195 and
U.S. Route 6 on Cape Cod, proceed east on U.S. Route 6 to the town of Onset.
The bench marks are in the vicinity of the Municipal Wharf. The tide gage and
staff were at the NE end of the Municipal Wharf.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 7277 D 1976
DESIGNATION: 844 7277 D TIDAL
MONUMENTATION: Tidal Station disk VM#: 5611
AGENCY: National Ocean Survey (NOS) PID:
SETTING CLASSIFICATION: Concrete wall
The primary bench mark is a disk set flush in the top of a concrete wall
separating the parking lot from the wharf, 18.17 m (59.6 ft) east of the SW
wharf light, 0.70 m (2.3 ft) north of the Harbor Master's office, and 0.46 m
(1.5 ft) above ground level.
BENCH MARK STAMPING: NO 2 1931
DESIGNATION: 844 7277 TIDAL 2
MONUMENTATION: Tidal Station disk VM#: 5612
AGENCY: US Coast & Geodetic Survey (USC&GS) PID:
SETTING CLASSIFICATION: Concrete curb
The bench mark is a disk set in the concrete curb, 1 m (4 ft) from the corner in
the NW corner of Bay View Park at the corner of Onset Avenue and wharf parking
area, and 0.3 m (1 ft) east of the street.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 8447277 PUBLICATION DATE: 06/28/2004
Name: ONSET BEACH T-12
MASSACHUSETTS
NOAA Chart: 13246 Latitude: 41° 44.5' N
USGS Quad: ONSET Longitude: 70° 39.5' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 7277 E 1976
DESIGNATION: 844 7277 E TIDAL
MONUMENTATION: Tidal Station disk VM#: 5613
AGENCY: National Ocean Survey (NOS) PID:
SETTING CLASSIFICATION: Concrete curbing wall
The bench mark is a disk set flush in the top of a concrete curbing wall
parallel to the sidewalk on Onset Avenue, across the street from the town wharf,
55.99 m (183.7 ft) east of the NE corner of Union and Onset Avenues, 11 m (36
ft) SE of the entrance to Ebb Tide Restaurant, 10.21 m (33.5 ft) north of the
centerline of Onset Avenue, and 0.15 m (0.5 ft) above ground level.
BENCH MARK STAMPING: 7277 F 1976
DESIGNATION: 844 7277 F TIDAL
MONUMENTATION: Tidal Station disk VM#: 5614
AGENCY: National Ocean Survey (NOS) PID:
SETTING CLASSIFICATION: Concrete landing step
The bench mark is a disk set flush in the top of the first concrete landing step
leading to the park on the west end of Hungry Beach Comber Snack Bar adjacent to
the town wharf, 22.28 m (73.1 ft) west of the centerline of a driveway that
surrounds the wharf parking lot, 12 m (39 ft) north of the beach line, and 2.56
m (8.4 ft) NE of the NE corner of the snack bar.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 8447277 PUBLICATION DATE: 06/28/2004
Name: ONSET BEACH T-12
MASSACHUSETTS
NOAA Chart: 13246 Latitude: 41° 44.5' N
USGS Quad: ONSET Longitude: 70° 39.5' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 1 1931
DESIGNATION: 844 7277 TIDAL 1
MONUMENTATION: Tidal Station disk VM#: 5615
AGENCY: US Coast & Geodetic Survey (USC&GS) PID:
SETTING CLASSIFICATION: Concrete curb
The bench mark is a disk set in the center of the top of a concrete curb, 18 m
(59 ft) south of the center of Onset Avenue, 1 m (3 ft) from the east end of the
curb, and 1 m (2 ft) from the street level in line with the west side of Kenny's
Pier and Salt Water Taffy stand.
BENCH MARK STAMPING: 7277 F 1977
DESIGNATION: 844 7277 F TIDAL RM 1
MONUMENTATION: Reference Mark disk VM#: 5616
AGENCY: National Ocean Survey (NOS) PID:
SETTING CLASSIFICATION: Sidewalk
The bench mark is a disk set in the concrete sidewalk near the NW corner of the
wharf parking lot at the NE edge of Bay View Park, by the entrance to the access
road to the snack bar/bath house, and 9 m (30 ft) north of the concrete curb
along the western side of the parking lot.
BENCH MARK STAMPING: 7277 H 1977
DESIGNATION: 844 7277 H TIDAL
MONUMENTATION: Tidal Station disk VM#: 5617
AGENCY: National Ocean Survey (NOS) PID:
SETTING CLASSIFICATION: Concrete parking lot
The bench mark is a disk set on the western edge of the concrete wharf parking
lot, approximately halfway between the foot and the end of the pier, 3 m (10 ft)
west of the cement curbstone, and 0.3 m (1 ft) east of the west edge of the
wharf.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 8447277 PUBLICATION DATE: 06/28/2004
Name: ONSET BEACH T-12
MASSACHUSETTS
NOAA Chart: 13246 Latitude: 41° 44.5' N
USGS Quad: ONSET Longitude: 70° 39.5' W
T I D A L D A T U M S
Tidal datums at ONSET BEACH T-12 based on:
LENGTH OF SERIES: 3 MONTHS
TIME PERIOD: August 1976 - October 1976
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8447930 WOODS HOLE, BUZZARDS BAY
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER (MHHW) = 1.244
MEAN HIGH WATER (MHW) = 1.135
MEAN TIDE LEVEL (MTL) = 0.601
MEAN SEA LEVEL (MSL) = 0.537
MEAN LOW WATER (MLW) = 0.067
MEAN LOWER LOW WATER (MLLW) = 0.000
National Geodetic Vertical Datum (NGVD 29)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
7277 D 1976 3.609 2.474
NO 2 1931 4.733 3.598
7277 E 1976 4.145 3.010
7277 F 1976 4.106 2.971
NO 1 1931 2.938 1.803
7277 F 1977 3.007 1.872
7277 H 1977 2.876 1.741
Foot Notes:
Bench marks 7277 F 1976 and NO 1 1931 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 5 of 5
Station ID: 8447277 PUBLICATION DATE: 06/28/2004
Name: ONSET BEACH T-12
MASSACHUSETTS
NOAA Chart: 13246 Latitude: 41° 44.5' N
USGS Quad: ONSET Longitude: 70° 39.5' 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.