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Bench Mark Sheet for 8449130, Nantucket Island MA

Superseded Epoch

Large map location marker Station Location
Small red map location marker Published bench mark
Small blue map location marker Unpublished bench mark

Bench mark positions only appear on the map if their coordinates in the CO-OPS database are at the precision of degrees/minutes/seconds/and tenths of seconds. If the coordinates are less precise, the mark will not appear.

Printable version

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  6

                                                                                
Station ID: 8449130                         PUBLICATION DATE:  04/21/2003
Name:       NANTUCKET ISLAND, NANTUCKET SOUND                 
            MA
NOAA Chart: 13241                           Latitude:   41° 17.1' N (  41.28500)
USGS Quad:  NANTUCKET                       Longitude:  70°  5.8' W ( -70.09670)


To reach the tidal bench marks from mainland it is necessary to take a ferry
boat either from Woods Hole or Hyannis.  Reservations are required for vehicles
during the summer months.  Nantucket is also serviced by air from the airports
in Hyannis and Boston.  The tide gage and staff are in the town of Nantucket at
the ferry terminal.  The bench marks are within a 2 km (1 mi) radius of the tide
station.


                         T I D A L   B E N C H   M A R K S


                 PRIMARY BENCH MARK STAMPING:  NO 25 1968
                         DESIGNATION:          844 9130 TIDAL 25

MONUMENTATION:           Tidal Station disk                    VM#:          209
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:        
SETTING CLASSIFICATION:  Concrete curb                         OPUS PID:        
LATITUDE:   41° 17.1' N (  41.28572)          LONGITUDE:  70°  5.8' W ( -70.09744)


The primary bench mark is a disk set in the top of a concrete curb near the
intersection of Broad Street and Easy Street, in line with the extended
centerline of Easy Street, 8.90 m (29.2 ft) north of the centerline of Broad
Street, 4.39 m (14.4 ft) NE of the NE face of a 1 m (3 ft) tall fire hydrant,
4.02 m (13.2 ft) east of a 1.07 m x 1.07 m x 1.31 m (3.5 ft x 3.5 ft x 4.3 ft)
transformer junction box, and 0.37 m (1.2 ft) above the sidewalk.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  6

                                                                                
Station ID: 8449130                         PUBLICATION DATE:  04/21/2003
Name:       NANTUCKET ISLAND, NANTUCKET SOUND                 
            MA
NOAA Chart: 13241                           Latitude:   41° 17.1' N (  41.28500)
USGS Quad:  NANTUCKET                       Longitude:  70°  5.8' W ( -70.09670)


                         T I D A L   B E N C H   M A R K S


                         BENCH MARK STAMPING:  NO 22 1934
                         DESIGNATION:          844 9130 TIDAL 22

MONUMENTATION:           Tidal Station disk                    VM#:          207
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:        
SETTING CLASSIFICATION:  Sidewalk                              OPUS PID:        
LATITUDE:   41° 17.0' N (  41.28392)          LONGITUDE:  70°  5.9' W ( -70.09775)


The bench mark is a disk set in a concrete block in the east sidewalk along
South Water Street, 18.14 m (59.5 ft) north of the NE corner of the intersection
of Main Street and South Water Street, 8.72 m (28.6 ft) NW of the NW corner of
1772 Nantucket Maritime Galleries, and 5.03 m (16.5 ft) east of the centerline
of South Water Street.



                         BENCH MARK STAMPING:  NO 23 1934
                         DESIGNATION:          844 9130 TIDAL 23

MONUMENTATION:           Tidal Station disk                    VM#:          208
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:        
SETTING CLASSIFICATION:  Concrete driveway apron               OPUS PID:        
LATITUDE:   41° 17.1' N (  41.28492)          LONGITUDE:  70°  5.9' W ( -70.09867)


The bench mark is a disk set in a concrete driveway apron near the Police
Station at the NW corner of the intersection of Chestnut Street and South Water
Street, 11.28 m (37.0 ft) west of the centerline of South Water Street, 7.19 m
(23.6 ft) north of the centerline of Chestnut Street, and 0.34 m (1.1 ft) east
of the west face of the SE cornerstone inscribed 1929.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  6

                                                                                
Station ID: 8449130                         PUBLICATION DATE:  04/21/2003
Name:       NANTUCKET ISLAND, NANTUCKET SOUND                 
            MA
NOAA Chart: 13241                           Latitude:   41° 17.1' N (  41.28500)
USGS Quad:  NANTUCKET                       Longitude:  70°  5.8' W ( -70.09670)


                         T I D A L   B E N C H   M A R K S


                         BENCH MARK STAMPING:  9130 G 1976
                         DESIGNATION:          844 9130 G

MONUMENTATION:           Tidal Station disk                    VM#:          210
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Concrete retaining wall               OPUS PID:        
LATITUDE:   41° 17.1' N (  41.28553)          LONGITUDE:  70°  5.9' W ( -70.09819)


The bench mark is a disk set in the top of a concrete retaining wall, located
just below a sign inscribed Steamboat Wharf 1774, near the NE corner of the
intersection of Broad Street and North Beach Street, 15.42 m (50.6 ft) SE of the
SW corner of the Nantucket Bike Shop II, 1 m (3 ft) north of a brick sidewalk,
and 0.3 m (1 ft) above the sidewalk.



                         BENCH MARK STAMPING:  9130 H
                         DESIGNATION:          844 9130 H

MONUMENTATION:           Tidal Station disk                    VM#:          211
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Concrete foundation                   OPUS PID:        
LATITUDE:   41° 17.3' N (  41.28792)          LONGITUDE:  70°  5.8' W ( -70.09717)


The bench mark is a disk set in the west corner of a 1.95 m x 2.47 m (6.4 ft x
8.1 ft) concrete storm sewer check trap, located at the intersection of Walsh
Street and Harbor View Way, 30.69 m (100.7 ft) SW of the flagpole on the White
Elephant property, 5.91 m (19.4 ft) east of the extended centerline of Walsh
Street, 4.27 m (14.0 ft) north of the centerline of a boat ramp at the outside
corner of the intersection of Harbor View Way and Walsh Street, and 0.03 m (0.1
ft) above the street.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  6

                                                                                
Station ID: 8449130                         PUBLICATION DATE:  04/21/2003
Name:       NANTUCKET ISLAND, NANTUCKET SOUND                 
            MA
NOAA Chart: 13241                           Latitude:   41° 17.1' N (  41.28500)
USGS Quad:  NANTUCKET                       Longitude:  70°  5.8' W ( -70.09670)


                         T I D A L   B E N C H   M A R K S


                         BENCH MARK STAMPING:  9130 K 1981
                         DESIGNATION:          844 9130 K

MONUMENTATION:           Tidal Station disk                    VM#:          212
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  AJ4032
SETTING CLASSIFICATION:  Galvanized steel rod                  OPUS PID#: AJ4032
LATITUDE:   41° 17.4' N (  41.28925)          LONGITUDE:  70°  5.6' W ( -70.09272)


The bench mark is a disk located in the SW corner of the U.S. Coast Guard Base
at Brant Point, 30.02 m (98.5 ft) south of the SE corner of the base garage,
24.08 m (79.0 ft) SW of the south corner of the main Coast Guard building, and
16.15 m (53.0 ft) north of the south face of the bulkhead. The bench mark is 3
cm (0.1 ft) below ground, crimped to a galvanized steel rod driven 14.6 m (48
ft) to refusal, and encased in a 6 inch PVC pipe with concrete kickblock.



                         BENCH MARK STAMPING:  9130 L 1981
                         DESIGNATION:          844 9130 L

MONUMENTATION:           Tidal Station disk                    VM#:          213
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Galvanized steel rod                  OPUS PID:        
LATITUDE:   41° 17.4' N (  41.28992)          LONGITUDE:  70°  5.5' W ( -70.09225)


The bench mark is a disk located in the NE corner of the U.S. Coast Guard Base
at Brant Point, 26.21 m (86.0 ft) NE of the NE face of an old lighthouse, 8.63 m
(28.3 ft) east of the east face of the 2 m x 2 m (5 ft x 5 ft) white building
beneath the range marker, 5.49 m (18.0 ft) south of the centerline of Easton
Street, and 1.07 m (3.5 ft) south of the NE fence corner of the base.  The bench
mark is 6 cm (0.2 ft) below ground, crimped to a galvanized steel rod driven
17.1 m (56 ft) to refusal, and encased in a 6 inch PVC pipe with concrete
kickblock.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  5 of  6

                                                                                
Station ID: 8449130                         PUBLICATION DATE:  04/21/2003
Name:       NANTUCKET ISLAND, NANTUCKET SOUND                 
            MA
NOAA Chart: 13241                           Latitude:   41° 17.1' N (  41.28500)
USGS Quad:  NANTUCKET                       Longitude:  70°  5.8' W ( -70.09670)


                            T I D A L   D A T U M S 


Tidal datums at NANTUCKET ISLAND, NANTUCKET SOUND 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 (10/30/1991)         =  2.398
     MEAN HIGHER HIGH WATER                     MHHW   =  1.089
     MEAN HIGH WATER                            MHW    =  0.986
     MEAN SEA LEVEL                             MSL    =  0.539
     MEAN TIDE LEVEL                            MTL    =  0.523
     MEAN LOW WATER                             MLW    =  0.061
     MEAN LOWER LOW WATER                       MLLW   =  0.000
     LOWEST  OBSERVED WATER LEVEL (02/12/1981)         = -0.653

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     NO 25 1968                                  2.232    1.247
     NO 22 1934                                  2.770    1.785
     NO 23 1934                                  2.716    1.731
     9130 G 1976                                 2.294    1.308
     9130 H                                      1.763    0.777
     9130 K 1981                                 1.536    0.550
     9130 L 1981                                 1.887    0.902


                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  6 of  6

                                                                                
Station ID: 8449130                         PUBLICATION DATE:  04/21/2003
Name:       NANTUCKET ISLAND, NANTUCKET SOUND                 
            MA
NOAA Chart: 13241                           Latitude:   41° 17.1' N (  41.28500)
USGS Quad:  NANTUCKET                       Longitude:  70°  5.8' W ( -70.09670)


                             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.

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Products available at 8449130 Nantucket Island, MA

Revised: 08/08/2018
NOAA / National Ocean Service
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