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Bench Mark Sheet for 9462719, Akun Cove, Akun Island AK

Superseded Epoch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Small blue map location marker Unpublished bench mark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  5

                                                                                
Station ID: 9462719                         PUBLICATION DATE:  06/07/2010
Name:       AKUN COVE, AKUN ISLAND                            
            AK
NOAA Chart: 16520                           Latitude:   54° 14.0' N (  54.23330)
USGS Quad:  Unimak (A-5)                    Longitude: 165° 32.0' W (-165.53300)


To reach the tidal bench marks from Dutch Harbor, travel NNE 26 km (14 nm) to
the north side of Akutan Island, then proceed NE for 37 km (20 nm) to the
entrance to Akutan Pass between Akutan and Akun islands, then proceed east 26 km
(14 nm) to Billings Head at the NE point of Akun Island, then proceed 5 km (3
nm) south to Akun Bay, then proceed SW 6 km (3 nm) to Helianthus Cove.  The
bench marks are located on a rock ledge/bluff facing north.


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


                 PRIMARY BENCH MARK STAMPING:  1 1937
                         DESIGNATION:          946 2719 TIDAL 1

MONUMENTATION:           Tidal Station disk                    VM#:        19210
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Bedrock ledge                         OPUS PID:        
LATITUDE:   54° 14.4' N (  54.23947)          LONGITUDE: 165° 32.4' W (-165.53989)


The primary bench mark is set flush on a bedrock ledge projecting into the sea
from the NW point of the headland, 30.08 m (98.7 ft) west of bench mark 946 2719
TIDAL 3, 14.67 m (48.1 ft) NNE from 946 2719 Tidal 2, 6.48 m (21.3 ft) ENE of
the highest point in the middle of the finger like prolongation stretching
seaward in a NE orientation, and 1.37 m (4.5 ft) above the High Water Line
denoted by the barnacles.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  5

                                                                                
Station ID: 9462719                         PUBLICATION DATE:  06/07/2010
Name:       AKUN COVE, AKUN ISLAND                            
            AK
NOAA Chart: 16520                           Latitude:   54° 14.0' N (  54.23330)
USGS Quad:  Unimak (A-5)                    Longitude: 165° 32.0' W (-165.53300)


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


                         BENCH MARK STAMPING:  2 1937
                         DESIGNATION:          946 2719 TIDAL 2

MONUMENTATION:           Tidal Station disk                    VM#:        19211
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Rock ledge                            OPUS PID:        
LATITUDE:   54° 14.4' N (  54.23931)          LONGITUDE: 165° 32.4' W (-165.54003)


The bench mark is set flush on a rock ledge or bluff forming shoreline, 35.91 m
(117.8 ft) WSW from bench mark 946 2719 TIDAL 3, 15.01 m (49.2 ft) ENE of bench
mark 946 2719 TIDAL 4, 14.67 m (48.1 ft) east from bench mark 946 2719 TIDAL 1,
11.34 m (37.20 ft) south from the highest point in the middle of a bedrock
prolongation stretching seaward on a NE, 1.49 m (4.9  ft) south of the edge of
the rock ledge on which the rock is set, and 2.20 m (7.2  ft) slant height above
the mean high water line denoted by the bottom of the green algae and the top of
the barnacles.



                         BENCH MARK STAMPING:  3 1937
                         DESIGNATION:          946 2719 TIDAL 3

MONUMENTATION:           Tidal Station disk                    VM#:        19212
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Rock ledge                            OPUS PID:        
LATITUDE:   54° 14.4' N (  54.23944)          LONGITUDE: 165° 32.4' W (-165.53953)


The bench mark is set flush on a rock ledge or bluff forming shoreline, 35.91 m
(117.9 ft) ENE of bench mark 946 2719 TIDAL 2, 35.78 m (117.39 ft) east of the
highest point in the middle of a bedrock prolongation stretching seaward in a NE
orientation, 30.08 m (98.6  ft) east of bench mark 946 2719 TIDAL 1, and 2.5 m
(8.2  ft) above the mean high water ling denoted by the barnacles.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  5

                                                                                
Station ID: 9462719                         PUBLICATION DATE:  06/07/2010
Name:       AKUN COVE, AKUN ISLAND                            
            AK
NOAA Chart: 16520                           Latitude:   54° 14.0' N (  54.23330)
USGS Quad:  Unimak (A-5)                    Longitude: 165° 32.0' W (-165.53300)


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


                         BENCH MARK STAMPING:  4 1938
                         DESIGNATION:          946 2719 TIDAL 4

MONUMENTATION:           Tidal Station disk                    VM#:        19213
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Bedrock ledge                         OPUS PID:        
LATITUDE:   54° 14.4' N (  54.23925)          LONGITUDE: 165° 32.4' W (-165.54025)


The bench mark is set flush on a bedrock ledge projecting into the sea from the
NW point of the headland, 26.89 m (88.2 ft) SW from bench mark 946 2719 TIDAL 1,
21.06 m (69.1 ft) SW from the highest point in the middle of the fingerlike
bedrock prolongation stretching seaward in a NE orientation, 15.01 m (49.3 ft)
WSW from bench mark 946 2719 TIDAL 4, and 2.78 m (9.12 ft) slant height above
the mean high water line denoted by green algae and barnacles.



                         BENCH MARK STAMPING:  2719 A 2009
                         DESIGNATION:          946 2719 A

MONUMENTATION:           Tidal Station disk                    VM#:        19214
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Stainless steel rod                   OPUS PID#: BBBH93
LATITUDE:   54° 14.3' N (  54.23803)          LONGITUDE: 165° 32.5' W (-165.54108)


The bench mark is located 144 m (472 ft) north of the northern intersection
between a storm berm and a west facing bluff, 40.32 m (132.2 ft) SSW of a 2.0 m
(6.6 ft) high rock outcropping that protrudes NW from a NNW facing rock cliff,
2.48 m (8.1 ft) east of a grass ledge. The bench mark is set 9 cm (0.3 ft) below
the top of the logo cover, crimped to the top of a stainless steel rod, and
driven 6.96 m (22.8 ft) to refusal in the NOS logo cover.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  5

                                                                                
Station ID: 9462719                         PUBLICATION DATE:  06/07/2010
Name:       AKUN COVE, AKUN ISLAND                            
            AK
NOAA Chart: 16520                           Latitude:   54° 14.0' N (  54.23330)
USGS Quad:  Unimak (A-5)                    Longitude: 165° 32.0' W (-165.53300)


                            T I D A L   D A T U M S 


Tidal datums at AKUN COVE, AKUN ISLAND based on:

     LENGTH OF SERIES:      4 MONTHS
     TIME PERIOD:           May 2009 - August 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   =  0.940
     MEAN HIGH WATER                            MHW    =  0.880
     MEAN SEA LEVEL                             MSL    =  0.523
     MEAN TIDE LEVEL                            MTL    =  0.515
     MEAN LOW WATER                             MLW    =  0.150
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     1 1937                                      1.943    1.063
     2 1937                                      2.620    1.740
     3 1937                                      2.609    1.729
     4 1938                                      2.766    1.886
     2719 A 2009                                 3.128    2.248


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

                                                                                
Station ID: 9462719                         PUBLICATION DATE:  06/07/2010
Name:       AKUN COVE, AKUN ISLAND                            
            AK
NOAA Chart: 16520                           Latitude:   54° 14.0' N (  54.23330)
USGS Quad:  Unimak (A-5)                    Longitude: 165° 32.0' W (-165.53300)


                             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 9462719 Akun Cove, Akun Island, AK

Revised: 10/15/2013
NOAA / National Ocean Service
Web site owner: Center for Operational Oceanographic Products and Services