NOAA Web Site Link Tides and Currents Home Page Transparent placeholder image

Bench Mark Sheet for 9459251, Bird Island, Shumagin Bank 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Superseded Epoch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Small blue map location marker Unpublished bench mark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: 9459251                         PUBLICATION DATE:  11/07/2013
Name:       BIRD ISLAND, SHUMAGIN BANK                        
            AK
NOAA Chart: 16540                           Latitude:   54° 50.1' N (  54.83522)
USGS Quad:  SIMEONOF ISLAND (D-3)           Longitude: 159° 45.6' W (-159.75956)


To reach the tidal bench marks from Sand Point, AK by boat, start at the
entrance to the boat harbor and proceed for 0.30 nm (0.6 km), then proceed for
1.70 nm ( 3.1 km) heading toward Unga Island, then proceed for 13.00 nm (24.1
km) and continue past Unga Island, then proceed for 18.00 nm (33.3 km) on a
course of 180 T to 54 50 03.24  N, 160 20 26.58,  continuing past the SW point
of Nagai Island, then proceed for 20.00 nm (37.0 km) to the north eastern
prominent seaward point of Bird Island. The bench marks are located on the
outcroppings by the Northeast side of the main beach on the Northern side of
Bird Island, and on the beach itself.


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


                 PRIMARY BENCH MARK STAMPING:  9251 A  2013
                         DESIGNATION:          945 9251 A

MONUMENTATION:           Tidal Station disk                    VM#:        20848
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Bedrock Outcrop                       OPUS PID:        
LATITUDE:   54° 50.1' N (  54.83536)          LONGITUDE: 159° 45.7' W (-159.76103)


The primary benchmark is a disk set flush in a SW bedrock outcrop finger
extending into the water, W from the most NE point of the large cliff on the
main beach, 187.53 m (615.2 ft) NW from another prominent point of land on the
NW seaward point on the SW side of the main beach of Bird Island.

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

                                                                                
Station ID: 9459251                         PUBLICATION DATE:  11/07/2013
Name:       BIRD ISLAND, SHUMAGIN BANK                        
            AK
NOAA Chart: 16540                           Latitude:   54° 50.1' N (  54.83522)
USGS Quad:  SIMEONOF ISLAND (D-3)           Longitude: 159° 45.6' W (-159.75956)


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


                         BENCH MARK STAMPING:  9251 B 2013
                         DESIGNATION:          945 9251 B

MONUMENTATION:           Tidal Station disk                    VM#:        20849
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Bedrock Outcrop                       OPUS PID:        
LATITUDE:   54° 50.1' N (  54.83519)          LONGITUDE: 159° 45.5' W (-159.75889)


The benchmark is a disk set flush in a SW bedrock outcrop partially extending
into the water, SW  from a prominent point of land on the NW seaward point of
the NW side of the main beach of Bird Island.



                         BENCH MARK STAMPING:  9251 C 2013
                         DESIGNATION:          945 9251 C

MONUMENTATION:           Tidal Station disk                    VM#:        20850
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Boulder                               OPUS PID:        
LATITUDE:   54° 50.1' N (  54.83531)          LONGITUDE: 159° 45.5' W (-159.75806)


The benchmark is a disk set flush in the bedrock of a boulder outcrop 0.3 M (1
feet) from the base of a 100 ft tall partially vegetated S facing granite rock
wall on the NE side of main beach of Bird Island.

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

                                                                                
Station ID: 9459251                         PUBLICATION DATE:  11/07/2013
Name:       BIRD ISLAND, SHUMAGIN BANK                        
            AK
NOAA Chart: 16540                           Latitude:   54° 50.1' N (  54.83522)
USGS Quad:  SIMEONOF ISLAND (D-3)           Longitude: 159° 45.6' W (-159.75956)


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


                         BENCH MARK STAMPING:  9251 D 2013
                         DESIGNATION:          945 9251 D

MONUMENTATION:           Tidal Station disk                    VM#:        20851
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Bedrock                               OPUS PID:        
LATITUDE:   54° 50.1' N (  54.83475)          LONGITUDE: 159° 45.4' W (-159.75744)


The benchmark is a disk set flush in a bedrock outcrop at the base of a 100ft 50
 sloping vegetated cliff wall 20 ft N of a  small seasonal water, the base of
the cliff wall gives way to small scattered boulders and then beach NE  from the
first prominent seaward point of land delineating the end of the main beach on
the S shore of Bird Island.



                         BENCH MARK STAMPING:  9521 E 2013
                         DESIGNATION:          9459521 E

MONUMENTATION:           Tidal Station disk                    VM#:        20852
AGENCY:                  National Ocean Service                IDB PID#:        
SETTING CLASSIFICATION:  Boulder                               OPUS PID:        
LATITUDE:   54° 50.1' N (  54.83421)          LONGITUDE: 159° 45.4' W (-159.75744)


The benchmark is a disk set flush in a boulder outcrop extending, approximately
1 m (3 ft) W of a 100ft  cliff wall that gives way to large cobble stones at its
base and 25 m (82 ft) N from the prominent seaward point of land delineating the
bay on the S shore of Bird Island.

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

                                                                                
Station ID: 9459251                         PUBLICATION DATE:  11/07/2013
Name:       BIRD ISLAND, SHUMAGIN BANK                        
            AK
NOAA Chart: 16540                           Latitude:   54° 50.1' N (  54.83522)
USGS Quad:  SIMEONOF ISLAND (D-3)           Longitude: 159° 45.6' W (-159.75956)


                            T I D A L   D A T U M S 


Tidal datums at BIRD ISLAND, SHUMAGIN BANK based on:

     LENGTH OF SERIES:      1 MONTH
     TIME PERIOD:           July 14, 2013 - August 13, 2013
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  9459450 SAND POINT, POPOF ISLAND


Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:

     MEAN HIGHER HIGH WATER                     MHHW   =  2.148
     MEAN HIGH WATER                            MHW    =  1.928
     MEAN TIDE LEVEL                            MTL    =  1.172
     MEAN SEA LEVEL                             MSL    =  1.158
     MEAN LOW WATER                             MLW    =  0.417
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     9251 A  2013                                2.950    1.022
     9251 B 2013                                 2.823    0.896
     9251 C 2013                                 3.293    1.366
     9251 D 2013                                 3.138    1.211
     9521 E 2013                                 3.324    1.397


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

                                                                                
Station ID: 9459251                         PUBLICATION DATE:  11/07/2013
Name:       BIRD ISLAND, SHUMAGIN BANK                        
            AK
NOAA Chart: 16540                           Latitude:   54° 50.1' N (  54.83522)
USGS Quad:  SIMEONOF ISLAND (D-3)           Longitude: 159° 45.6' W (-159.75956)


                             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.

Return to Top
Products available at 9459251 Bird Island, Shumagin Bank, AK

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