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Datums Page Page 1 of 5
Station ID: 8410834 PUBLICATION DATE: 11/19/2010
Name: PETTEGROVE POINT, DOCHET ISLAND
ME
NOAA Chart: 13398 Latitude: 45° 7.7' N ( 45.12844)
USGS Quad: DEVILS HEAD Longitude: 67° 8.7' W ( -67.14467)
To reach the tide station from the Post Office in Robbinston Maine travel north
on US Route 1 (River Rd) 5.47 km (3.4 mi), turn right onto St. Croix Drive
travel north around the bend for 0.32 km (0.2 mi) to 60 St Croix Drive on the
right, on the northern end of the property near the road is the gated beginning
of a dirt road, follow the dirt road generally west for 0.23 km (0.14 mi) down
to the lower lawn of the same property, cross the lawn 87 m (286 ft) to the WNW
to the station. The tide house was on the knoll at the end of the point out
into the St Croix river and the bench marks are in the lawn and the beach
surrounding it.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 0834 A 2010
DESIGNATION: 8410834 A
MONUMENTATION: Tidal Station disk VM#: 19718
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: bedrock OPUS PID:
LATITUDE: 45° 7.6' N ( 45.12692) LONGITUDE: 67° 8.7' W ( -67.14561)
The primary bench mark is set flush in bedrock on the southern end of the beach
that forms the southern side of Pettegrove Point, 61.59 m (202.1 ft) SSW of
bench mark 8410834 B, 55.35 m (181.6 ft) SSW of the southern most corner of the
beach shack on the point, 13.30 m (43.6 ft) SSE of the center of the end of a
small ravine cut into the southern end of the bank that runs SW to NE above the
beach, and 1.24 m (4.1 ft) above the beach
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 8410834 PUBLICATION DATE: 11/19/2010
Name: PETTEGROVE POINT, DOCHET ISLAND
ME
NOAA Chart: 13398 Latitude: 45° 7.7' N ( 45.12844)
USGS Quad: DEVILS HEAD Longitude: 67° 8.7' W ( -67.14467)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: Unstamped
DESIGNATION: 8410834 Wilson
MONUMENTATION: Tidal Station disk VM#: 19719
AGENCY: US Coast & Geodetic Survey IDB PID#: QF0693
SETTING CLASSIFICATION: burried boulder OPUS PID:
LATITUDE: 45° 7.7' N ( 45.12839) LONGITUDE: 67° 8.7' W ( -67.14472)
The bench mark is set flush in the top of a buried boulder on the northern end
of the tree and grass covered knoll near the end of Pettegrove Point, 117.9 m
(386 ft) NW of bench mark 8410834 C, 46.10 m (151.2 ft) north of the center of
the northwestern end of the sandbar section of the point where it meets the
rocky islet end, 4.30 m (14.1 ft) south of the line where the rock changes in
color from black to red, and 2.30 m (7.5 ft) north of tree line.
BENCH MARK STAMPING: 0834 B 2010
DESIGNATION: 8410834 B
MONUMENTATION: Tidal Station disk VM#: 19720
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: bedrock OPUS PID#: BBCB15
LATITUDE: 45° 7.6' N ( 45.12739) LONGITUDE: 67° 8.7' W ( -67.14525)
The bench mark is set flush in the top of exposed bedrock on the beach that
forms the southern side of the base of Pettegrove Point, 61.59 m (202.1 ft) NNE
of bench mark 8410834 A, 58.13 m (190.7 ft) SE of bench mark 8410834 C, 52.90 m
(173.6 ft) NE of the center of the end of a small ravine cut into the embankment
above the southern end of the beach, 18.75 m (61.5 ft) SE of the southern most
corner of the beach shack on the point, and 12.50 m (41.0 ft) SE of the
vegetation line along the top of the beach.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 8410834 PUBLICATION DATE: 11/19/2010
Name: PETTEGROVE POINT, DOCHET ISLAND
ME
NOAA Chart: 13398 Latitude: 45° 7.7' N ( 45.12844)
USGS Quad: DEVILS HEAD Longitude: 67° 8.7' W ( -67.14467)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 0834 C 2010
DESIGNATION: 8410834 C
MONUMENTATION: Tidal Station disk VM#: 19721
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: bedrock outcrop OPUS PID#: BBBW07
LATITUDE: 45° 7.7' N ( 45.12772) LONGITUDE: 67° 8.7' W ( -67.14581)
The bench mark is set flush in the top of exposed bedrock ledge extending NNE
into the water on the beach that forms the northern side of the base of
Pettegrove Point, 117.9 m (386 ft) SE of bench mark 8410834 WILSON, 64.32 m
(211.0 ft) NE of bench mark 8410834 D, 58.13 m (190.7 ft) NW of bench mark
8410834 B, 38.94 m (127.8 ft) NNE of the northern most corner of the beach shack
on the point, and 4.20 m (13.8 ft) NE of the edge of vegetation.
BENCH MARK STAMPING: 0834 D 2010
DESIGNATION: 8410834 D
MONUMENTATION: Tidal Station disk VM#: 19722
AGENCY: National Oceaan Service (NOS) IDB PID#:
SETTING CLASSIFICATION: boulder OPUS PID:
LATITUDE: 45° 7.6' N ( 45.12733) LONGITUDE: 67° 8.8' W ( -67.14628)
The bench mark is set flush in the top of a partially buried 2.72 m x 1.39 m x
0.61 m (8.9 ft x 4.6 ft x 2.0 ft) boulder on the western side of the lawn at the
base of Pettegrove Point, 64.32 m (211.0 ft) SW of bench mark 8410834 C, 14.17 m
(46.5 ft) SSE of the centerline of the end of the dirt road that leads down to
the lawn from St Croix Drive, 5.49 m (18.0 ft) east of the western edge of the
lawn, and 0.61 m (2.0 ft) above grade.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 8410834 PUBLICATION DATE: 11/19/2010
Name: PETTEGROVE POINT, DOCHET ISLAND
ME
NOAA Chart: 13398 Latitude: 45° 7.7' N ( 45.12844)
USGS Quad: DEVILS HEAD Longitude: 67° 8.7' W ( -67.14467)
T I D A L D A T U M S
Tidal datums at PETTEGROVE POINT, DOCHET ISLAND based on:
LENGTH OF SERIES: 7 MONTHS
TIME PERIOD: April 2010 - October 2010
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8410140 EASTPORT, PASSAMAQUODDY BAY
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 6.252
MEAN HIGH WATER MHW = 6.104
MEAN SEA LEVEL MSL = 3.129
MEAN TIDE LEVEL MTL = 3.121
MEAN LOW WATER MLW = 0.138
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
0834 A 2010 7.594 1.490
Unstamped 8.158 2.054
0834 B 2010 6.759 0.655
0834 C 2010 7.239 1.135
0834 D 2010 12.308 6.204
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 8410834 PUBLICATION DATE: 11/19/2010
Name: PETTEGROVE POINT, DOCHET ISLAND
ME
NOAA Chart: 13398 Latitude: 45° 7.7' N ( 45.12844)
USGS Quad: DEVILS HEAD Longitude: 67° 8.7' W ( -67.14467)
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.
Station Location
Published bench mark
Unpublished bench mark
