U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 9462694 PUBLICATION DATE: 06/19/2009
Name: AKUTAN
AK
NOAA Chart: 16532 Latitude: 54° 8.0' N ( 54.13328)
USGS Quad: UNIMAK A-6 Longitude: 165° 46.6' W (-165.77731)
To reach the tide station from the float plane haul-out ramp, travel SE
approximately 100 m (330 ft) to the chain-link fence at the city dock, turn
right and proceed south approximately 20 m (66 ft) to the west face of an orange
conex shipping container which is used for storage. The bench marks are located
in the vicinity of the dock and on the float plane haul-out ramp.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 2694 A 2009
DESIGNATION: 946 2694 A
MONUMENTATION: Tidal Station disk VM#: 19205
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete slab OPUS PID#: BBBH20
LATITUDE: 54° 8.0' N ( 54.13311) LONGITUDE: 165° 46.6' W (-165.77697)
The primary bench mark is set flush in the concrete slab foundation of the
south-eastern most bollard along the sheet-pile retaining wall abutting the city
dock, 29.25 m (96.0 ft) SE of bench mark 946 2694 B, 1.30 m (4.3 ft) NW of the
outside edge of the retaining wall, 1.26 m (4.1 ft) NE of the outside edge of
the retaining wall, and 0.45 m (1.5 ft) north of the center of the south-eastern
most bollard.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 9462694 PUBLICATION DATE: 06/19/2009
Name: AKUTAN
AK
NOAA Chart: 16532 Latitude: 54° 8.0' N ( 54.13328)
USGS Quad: UNIMAK A-6 Longitude: 165° 46.6' W (-165.77731)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 2694 B 2009
DESIGNATION: 946 2694 B
MONUMENTATION: Tidal Station disk VM#: 19206
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete slab OPUS PID:
LATITUDE: 54° 8.0' N ( 54.13328) LONGITUDE: 165° 46.6' W (-165.77731)
The bench mark is set flush in the concrete slab foundation of the north-western
most bollard along the sheet-pile retaining wall abutting the city dock, 46.28 m
(151.8 ft) south of bench mark 946 2694 C, 29.25 m (96.0 ft) NW of bench mark
946 2694 A, 3.48 m (11.4 ft) west of a red fire hydrant, 1.50 m (4.9 ft) NE of
the center of the north-western most bollard inside of the retaining wall, and
0.68 m (2.2 ft) south of the northern edge of the retaining wall.
BENCH MARK STAMPING: 2694 C 2009
DESIGNATION: 946 2694 C
MONUMENTATION: Tidal Station disk VM#: 19207
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete slab OPUS PID:
LATITUDE: 54° 8.0' N ( 54.13361) LONGITUDE: 165° 46.6' W (-165.77689)
The bench mark is a set flush in concrete on the south east side of the
threshold of the overhead door leading to the Post Office warehouse, 46.28 m
(151.8 ft) north of bench mark 946 2694 B, 41.25 m (135.3 ft) east of bench mark
946 2694 D, 35.81m (117.5 ft) NNE of the center of the top of the ramp down to
the floating skiff moorage, 10.72 m (35.2 ft) ESE of the western most outside
corner of the warehouse, and 0.18 m (0.6 m) WNW of the south eastern edge of the
overhead door.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 9462694 PUBLICATION DATE: 06/19/2009
Name: AKUTAN
AK
NOAA Chart: 16532 Latitude: 54° 8.0' N ( 54.13328)
USGS Quad: UNIMAK A-6 Longitude: 165° 46.6' W (-165.77731)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 2694 D 2009
DESIGNATION: 946 2694 D
MONUMENTATION: Tidal Station disk VM#: 19208
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete structure OPUS PID:
LATITUDE: 54° 8.0' N ( 54.13369) LONGITUDE: 165° 46.7' W (-165.77758)
The bench mark is a disk set flush in concrete on the northern end of the large
concrete structure used as backfill for the sheet-pile wall defining the inner
side of the skiff moorage, 66.03m (216.6ft) ESE of bench mark 2694 E 2009,
41.25m (135.3ft) west of bench mark 2694 C 2009, 40.95m (134.4ft) NE of the
center of the top of the ramp down to the floating skiff moorage, 2.72m (8.9ft)
NE of the SW edge of the concrete structure, and 0.25m (0.8ft) SE of the NW edge
of the concrete structure.
BENCH MARK STAMPING: 2694 E 2009
DESIGNATION: 946 2694 E
MONUMENTATION: Tidal Station disk VM#: 19209
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete pad OPUS PID:
LATITUDE: 54° 8.0' N ( 54.13397) LONGITUDE: 165° 46.7' W (-165.77853)
The bench mark is set flush in the concrete pad of the float plane haul-out west
of the west edge of the ramp, 66.03 m (216.6 ft) WNW of bench mark 946 2694 D,
35.50 m (116.5 ft) ESE of the corner of the block retaining wall around the
church, 8.03 m (26.3 ft) west of the centerline of the floatplane haul-out ramp,
and 4.55 m (14.9 ft) north of the southern edge of the concrete pad.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 9462694 PUBLICATION DATE: 06/19/2009
Name: AKUTAN
AK
NOAA Chart: 16532 Latitude: 54° 8.0' N ( 54.13328)
USGS Quad: UNIMAK A-6 Longitude: 165° 46.6' W (-165.77731)
T I D A L D A T U M S
Tidal datums at AKUTAN based on:
LENGTH OF SERIES: 1 MONTH
TIME PERIOD: April 2009 - April 2009
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 9462620 UNALASKA, DUTCH HARBOR
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 1.138
MEAN HIGH WATER MHW = 1.044
MEAN SEA LEVEL MSL = 0.661
MEAN TIDE LEVEL MTL = 0.659
MEAN LOW WATER MLW = 0.274
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
2694 A 2009 3.355 2.311
2694 B 2009 3.293 2.249
2694 C 2009 3.639 2.595
2694 D 2009 2.674 1.630
2694 E 2009 2.042 0.998
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 9462694 PUBLICATION DATE: 06/19/2009
Name: AKUTAN
AK
NOAA Chart: 16532 Latitude: 54° 8.0' N ( 54.13328)
USGS Quad: UNIMAK A-6 Longitude: 165° 46.6' W (-165.77731)
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.