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National Ocean Service
Datums Page Page 1 of 8
Station ID: 8413825 PUBLICATION DATE: 08/22/2018
Name: MACKEREL COVE, SWANS ISLAND
ME
NOAA Chart: 13313 Latitude: 44° 10.2' N ( 44.17000)
USGS Quad: SWANS ISLAND Longitude: 68° 26.1' W ( -68.43500)
To reach the bench marks and the tide staff, proceed to the remote island of
Swan Island which is located off the coast of Maine near Bar Harbor on Mount
Desert Island, proceed by ferry service originating in Bass Harbor 9.66 km (6
mi) to the island. The tide staff is located on the NE side of a wooden crib at
the Swans Island Ferry landing.
T I D A L B E N C H M A R K S
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 8
Station ID: 8413825 PUBLICATION DATE: 08/22/2018
Name: MACKEREL COVE, SWANS ISLAND
ME
NOAA Chart: 13313 Latitude: 44° 10.2' N ( 44.17000)
USGS Quad: SWANS ISLAND Longitude: 68° 26.1' W ( -68.43500)
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 3825 A 1994
DESIGNATION: TIDAL 3825 A
MONUMENTATION: Tidal Station disk VM#: 19242
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete cap OPUS PID:
LATITUDE: 44° 10.2' N ( 44.17000) LONGITUDE: 68° 26.1' W ( -68.43500)
The primary bench mark is a disk set flush in a concrete cap on the north side
of the ferry landing, on the NE corner of the cap, 6.38 m (20.9 ft) east of the
west end of the grated ramp, 5.35 m (17.6 ft) north of the centerline of the
metal grate ramp, and 0.45 m (1.5 ft) west of the east face of the cap.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 8
Station ID: 8413825 PUBLICATION DATE: 08/22/2018
Name: MACKEREL COVE, SWANS ISLAND
ME
NOAA Chart: 13313 Latitude: 44° 10.2' N ( 44.17000)
USGS Quad: SWANS ISLAND Longitude: 68° 26.1' W ( -68.43500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 3825 C 1994
DESIGNATION: TIDAL 3825 C
MONUMENTATION: Tidal Station disk VM#: 19243
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete cap OPUS PID:
LATITUDE: 44° 10.2' N ( 44.17000) LONGITUDE: 68° 26.1' W ( -68.43500)
The bench mark is a disk set flush in a concrete support of the metal ramp on
the north side of the ferry landing, 21.0 m (69.6 ft) east of the west end of
the metal grate ramp, 2.50 m (8.4 ft) NW of the centerline of the paved ferry
road, in the NE corner of the cap, 0.43 m (1.1 ft) north of a 0.91 m (3 ft) high
wing wall, being 0.93 m (3.0 ft) below the road.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 8
Station ID: 8413825 PUBLICATION DATE: 08/22/2018
Name: MACKEREL COVE, SWANS ISLAND
ME
NOAA Chart: 13313 Latitude: 44° 10.2' N ( 44.17000)
USGS Quad: SWANS ISLAND Longitude: 68° 26.1' W ( -68.43500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 3825 D 1994
DESIGNATION: TIDAL 3825 D
MONUMENTATION: Tidal Station disk VM#: 19244
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Wing wall OPUS PID:
LATITUDE: 44° 10.2' N ( 44.17000) LONGITUDE: 68° 26.1' W ( -68.43500)
The bench mark is a disk set flush in a concrete wing wall on the south side of
the metal ramp to the ferry, 2.22 m (7.3 ft) south of the centerline of the
paved road to the landing, 1.85 m (6.1 ft) east of the west end of the wing
wall, being 0.91 m (3 ft) above the road.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 8
Station ID: 8413825 PUBLICATION DATE: 08/22/2018
Name: MACKEREL COVE, SWANS ISLAND
ME
NOAA Chart: 13313 Latitude: 44° 10.2' N ( 44.17000)
USGS Quad: SWANS ISLAND Longitude: 68° 26.1' W ( -68.43500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 3825 E 1994
DESIGNATION: TIDAL 3825 E
MONUMENTATION: Tidal Station disk VM#: 19245
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Rock outcrop OPUS PID:
LATITUDE: 44° 10.2' N ( 44.17000) LONGITUDE: 68° 26.1' W ( -68.43500)
The bench mark is a disk set flush in a granite outcropping on the east side of
the Ticket Office and across the street in the woods, 29.35 m (96.3 ft) east of
the east face of the Ticket Office, 25.72 m (84.4 ft) SE of the center of 3
transformers elevated on a wooden platform, 1.78 m (5.8 ft) north of the south
edge of the rock outcrop, being approximately 2.44 m (8.0 ft) above the road.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 8
Station ID: 8413825 PUBLICATION DATE: 08/22/2018
Name: MACKEREL COVE, SWANS ISLAND
ME
NOAA Chart: 13313 Latitude: 44° 10.2' N ( 44.17000)
USGS Quad: SWANS ISLAND Longitude: 68° 26.1' W ( -68.43500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING:
DESIGNATION: TIDAL UNSTAMPED 1
ALIAS: NO STAMPING 1
MONUMENTATION: Tidal Station disk VM#: 19246
AGENCY: Unknown IDB PID#:
SETTING CLASSIFICATION: Concrete step OPUS PID:
LATITUDE: 44° 10.2' N ( 44.17000) LONGITUDE: 68° 26.1' W ( -68.43500)
The bench mark is a disk set flush in a concrete step on the NW face of the
Ferry Ticket Office in front of the entrance door, 9.80 m (12.2 ft) east of a
power pole with lite, 6.45 m (21.2 ft) NE of the centerline of the paved road to
Ferry Landing, 5.50 m (18.1 ft) south of the north corner of the Ticket Office,
being 0.15 m (0.5 ft) above ground.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 7 of 8
Station ID: 8413825 PUBLICATION DATE: 08/22/2018
Name: MACKEREL COVE, SWANS ISLAND
ME
NOAA Chart: 13313 Latitude: 44° 10.2' N ( 44.17000)
USGS Quad: SWANS ISLAND Longitude: 68° 26.1' W ( -68.43500)
T I D A L D A T U M S
Tidal datums at MACKEREL COVE, SWANS ISLAND based on:
LENGTH OF SERIES: 30 DAYS
TIME PERIOD: Sep 1 1994 - Sep 30 1994
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8413320 BAR HARBOR, FRENCHMAN BAY
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 3.330
MEAN HIGH WATER MHW = 3.204
MEAN SEA LEVEL MSL = 1.665
MEAN TIDE LEVEL MTL = 1.658
MEAN LOW WATER MLW = 0.112
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
3825 A 1994 4.471 1.267
3825 C 1994 3.647 0.443
3825 D 1994 5.294 2.090
3825 E 1994 8.944 5.740
TIDAL UNSTAMPED 1 6.356 3.152
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 8 of 8
Station ID: 8413825 PUBLICATION DATE: 08/22/2018
Name: MACKEREL COVE, SWANS ISLAND
ME
NOAA Chart: 13313 Latitude: 44° 10.2' N ( 44.17000)
USGS Quad: SWANS ISLAND Longitude: 68° 26.1' W ( -68.43500)
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.