U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 8447495 PUBLICATION DATE: 04/21/2003
Name: SAQUATUCKET HARBOR
MASSACHUSETTS
NOAA Chart: 13246 Latitude: 41° 40.1' N
USGS Quad: HARWICH Longitude: 70° 3.4' W
To reach the tidal bench marks from the intersection of Route 6 and 134 in South
Dennis, proceed south on Route 134 for 3.7 km (2.3 mi) to Route 28, then east on
Route 28 for 8.0 km (5.0 mi) to Saquatucket Harbor. The bench marks are in the
vicinity of the harbor parking lot, and the tide gauge and staff were attached
to floating dock pilings south of the Harbormaster's office.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 7495 A 1993
DESIGNATION: 844 7495 A
MONUMENTATION: Tidal Station disk VM#: 12472
AGENCY: National Ocean Service (NOS) PID:
SETTING CLASSIFICATION: Concrete sea wall
The primary bench mark is a disk set in the concrete seawall cap of Saquatucket
Harbor, 20.70 m (67.9 ft) east of the western corner of the sea wall, 7.92 m
(26.0 ft) SW of the NW corner of a small utility building, and 5.49 m (18.0 ft)
SW of the centerline of the small road fronting the harbor.
BENCH MARK STAMPING: 7495 B 1993
DESIGNATION: 844 7495 B
MONUMENTATION: Tidal Station disk VM#: 12473
AGENCY: National Ocean Service (NOS) PID:
SETTING CLASSIFICATION: Concrete wing wall
The bench mark is a disk set in the dogleg corner of the concrete wingwall on
the east side of Brax Landing Restaurant, 29.41 m (96.5 ft) north of the
westernmost group of piles at the entrance to the road fronting Saquatucket
Harbor, 13.87 m (45.5 ft) WSW of the edge of the Saquatucket Harbor parking lot,
10.21 m (33.5 ft) SE of the NE corner of Brax Landing, and 1.37 m (4.5 ft) above
grade.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 8447495 PUBLICATION DATE: 04/21/2003
Name: SAQUATUCKET HARBOR
MASSACHUSETTS
NOAA Chart: 13246 Latitude: 41° 40.1' N
USGS Quad: HARWICH Longitude: 70° 3.4' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 7495 C 1993
DESIGNATION: 844 7495 C
MONUMENTATION: Tidal Station disk VM#: 12474
AGENCY: National Ocean Service (NOS) PID:
SETTING CLASSIFICATION: Concrete foundation
The bench mark is a disk set in the southern edge of the 1 m (2 ft) diameter
concrete flagpole base at Thompsons Farm Market (710 Route 28), 24.38 m (80.0
ft) NE of telephone pole No. 81, 22.40 m (73.5 ft) SW of the SW corner of the
market, and 9.94 m (32.6 ft) NNW of the centerline of Route 28.
BENCH MARK STAMPING: 7495 D 1993
DESIGNATION: 844 7495 D
MONUMENTATION: Tidal Station disk VM#: 12475
AGENCY: National Ocean Service (NOS) PID:
SETTING CLASSIFICATION: Concrete head wall
The bench mark is a disk set in the western end of the lower tier of a concrete
headwall over the small stream just west of Saquatucket Harbor and on the south
side of Route 28, 11.37 m (37.3 ft) SSW of telephone pole No. 79, 8.99 m (29.5
ft) SSE of the centerline of Route 28, 0.46 m (1.5 ft) ENE of the western end of
the lower end of the headwall, and 2 m (6 ft) below the surface of the road.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 8447495 PUBLICATION DATE: 04/21/2003
Name: SAQUATUCKET HARBOR
MASSACHUSETTS
NOAA Chart: 13246 Latitude: 41° 40.1' N
USGS Quad: HARWICH Longitude: 70° 3.4' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: TBM SLAB 1993
DESIGNATION: 844 7495 TBM SLAB
MONUMENTATION: Survey disk VM#: 12476
AGENCY: US Army Corps of Engineers (USE) PID:
SETTING CLASSIFICATION: Concrete foundation
The bench mark is a disk set in the SW corner of a concrete pad supporting a
large green utility box adjacent to the harbormasters building, 15.24 m (50.0
ft) ENE of a large flagpole, 15.24 m (50.0 ft) NE of the seawall, and 5.88 m
(19.3 ft) SSE of the SE corner of the harbormaster building.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 8447495 PUBLICATION DATE: 04/21/2003
Name: SAQUATUCKET HARBOR
MASSACHUSETTS
NOAA Chart: 13246 Latitude: 41° 40.1' N
USGS Quad: HARWICH Longitude: 70° 3.4' W
T I D A L D A T U M S
Tidal datums at SAQUATUCKET HARBOR based on:
LENGTH OF SERIES: 5 Months
TIME PERIOD: May 1993 - September 1993
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8449130 NANTUCKET ISLAND, NANTUCKET SOUND
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER (MHHW) = 1.325
MEAN HIGH WATER (MHW) = 1.220
NORTH AMERICAN VERTICAL DATUM-1988 (NAVD) = 0.788
MEAN SEA LEVEL (MSL) = 0.682
MEAN TIDE LEVEL (MTL) = 0.652
MEAN LOW WATER (MLW) = 0.085
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
7495 A 1993 2.334 1.114
7495 B 1993 4.502 3.282
7495 C 1993 3.780 2.560
7495 D 1993 2.186 0.966
TBM SLAB 1993 3.330 2.110
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 8447495 PUBLICATION DATE: 04/21/2003
Name: SAQUATUCKET HARBOR
MASSACHUSETTS
NOAA Chart: 13246 Latitude: 41° 40.1' N
USGS Quad: HARWICH Longitude: 70° 3.4' 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.