U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 8447368 PUBLICATION DATE: 04/21/2010
Name: GREAT HILL
MA
NOAA Chart: 13236 Latitude: 41° 42.7' N ( 41.71170)
USGS Quad: ONSET Longitude: 70° 42.9' W ( -70.71500)
From the town of Wareham and the memorial town hall on 6W, go west on 6W for 2.7
miles (4.3 km) to Point road on left. Turn east (left) on Point road and proceed
2.0 miles (3.2 km) to Delano road on left and turn left on Delano road and go
1.5 miles (2.4 km ) on Delano road until you come to an iron gate for the Great
Hill estate property turn right thru the gate and travel 0.6 miles ( 0.9 km )
along the shore to a concrete pier and the station. The bench marks are along
the water.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 7368 C 1977
DESIGNATION: 844 7368 C TIDAL
MONUMENTATION: Tidal Station disk VM#: 2036
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Boulder OPUS PID:
LATITUDE: 41° 42.5' N ( 41.70872) LONGITUDE: 70° 42.0' W ( -70.70011)
The disk is set flush in a granite boulder located on the property of Great Hill
estate at the easterly side of the property and SE of a bathhouse and near a
bench on the bluff, 36.11 m (118.5 ft) east of a flagpole, 12.91 m (42.4 ft) ESE
of the south side of a bench, 2.81 m (9.2 ft) NE of the edge of the bluff.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 8447368 PUBLICATION DATE: 04/21/2010
Name: GREAT HILL
MA
NOAA Chart: 13236 Latitude: 41° 42.7' N ( 41.71170)
USGS Quad: ONSET Longitude: 70° 42.9' W ( -70.71500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 7368 F 2009
DESIGNATION: 844 7368 F
MONUMENTATION: Tidal Station disk VM#: 19170
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Granite boulder OPUS PID:
LATITUDE: 41° 42.6' N ( 41.71019) LONGITUDE: 70° 42.9' W ( -70.71519)
The bench mark is set flush in a granite boulder located on the property of the
Great Hill Estate at the north corner of the bathhouse building near the water,
55.92 m (183.46 ft) SE of bench mark 844 7368 E, 22.72 m (74.54 ft) NE of the
centerline of a paved road, and 2.86 m (9.38 ft) north of the bottom step to the
bathhouse.
BENCH MARK STAMPING: 7368 E 2009
DESIGNATION: 844 7368 E
MONUMENTATION: Tidal Station disk VM#: 19171
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete dock OPUS PID#: BBDQ20
LATITUDE: 41° 38.6' N ( 41.64392) LONGITUDE: 70° 42.9' W ( -70.71542)
The bench mark is set flush in the SE corner of a concrete dock near the paved
road located on the property of the Great Hill Estate, 44.03 m (144.6 ft) SSE
of bench mark 844 7368 D, 7.55 m (24.77 ft) SE of the SW corner of the dock, and
2.36 m (7.74 ft) north of the shore end of the dock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 8447368 PUBLICATION DATE: 04/21/2010
Name: GREAT HILL
MA
NOAA Chart: 13236 Latitude: 41° 42.7' N ( 41.71170)
USGS Quad: ONSET Longitude: 70° 42.9' W ( -70.71500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 7368 D 2009
DESIGNATION: 844 7368 D
MONUMENTATION: Tidal Station disk VM#: 19172
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete dock OPUS PID:
LATITUDE: 41° 42.7' N ( 41.71089) LONGITUDE: 70° 42.9' W ( -70.71503)
The bench mark is set on a concrete dock in the NE corner of the dock next to
the NOAA tide shelter located on the property of the Great Hill Estate, 46.62 m
(153.0 ft) NNE of the south face of the dock, 16.52 m (54.2 ft) SE of the NW
corner of the dock, and 1.12 m (3.7 ft) SW of the NE corner of the dock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 8447368 PUBLICATION DATE: 04/21/2010
Name: GREAT HILL
MA
NOAA Chart: 13236 Latitude: 41° 42.7' N ( 41.71170)
USGS Quad: ONSET Longitude: 70° 42.9' W ( -70.71500)
T I D A L D A T U M S
Tidal datums at GREAT HILL based on:
LENGTH OF SERIES: 6 MONTHS
TIME PERIOD: May 2009 - October 2009
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8452660 NEWPORT, NARRAGANSETT BAY
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 1.345
MEAN HIGH WATER MHW = 1.264
MEAN TIDE LEVEL MTL = 0.660
MEAN SEA LEVEL MSL = 0.590
MEAN LOW WATER MLW = 0.055
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
7368 C 1977 4.102 2.838
7368 F 2009 3.521 2.257
7368 E 2009 2.087 0.823
7368 D 2009 2.050 0.786
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 8447368 PUBLICATION DATE: 04/21/2010
Name: GREAT HILL
MA
NOAA Chart: 13236 Latitude: 41° 42.7' N ( 41.71170)
USGS Quad: ONSET Longitude: 70° 42.9' W ( -70.71500)
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.