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Bench Mark Sheet for 9458779, NAKCHAMIK ISLAND, CHIGNIK BAY 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Superseded Epoch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Small blue map location marker Unpublished bench mark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: 9458779                         PUBLICATION DATE:  04/29/2004
Name:       NAKCHAMIK ISLAND, PACIFIC OCEAN                   
            AK
NOAA Chart: 16566                           Latitude:   56° 21.1' N (  56.35170)
USGS Quad:  SUTWIK ISLAND (B-6)             Longitude: 157° 48.7' W (-157.81200)


To reach the tidal bench marks from Alaska Peninsula, go to the east side of
Nakchamik Island on the northern coast of the Chignik Bay.  The bench marks were
located on the southern end of Cobble Beach.  The tide gauge was located on the
beach.


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


                 PRIMARY BENCH MARK STAMPING:  8779 A 1996
                         DESIGNATION:          945 8779 A

MONUMENTATION:           Tidal Station disk                    VM#:        13146
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Rock outcrop                          OPUS PID:        
LATITUDE:   56° 21.1' N (  56.35170)          LONGITUDE: 157° 48.7' W (-157.81200)


The primary bench mark is a disk set at the base of a rocky outcrop, 250 m (820
ft) NW (340 degrees magnetic) from bench mark 8779 B 1996, and 0.50 m (1.6 ft)
above the north end of a cobble beach.



                         BENCH MARK STAMPING:  8779 B 1996
                         DESIGNATION:          945 8779 B

MONUMENTATION:           Tidal Station disk                    VM#:        13147
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Boulder                               OPUS PID:        
LATITUDE:   56° 21.1' N (  56.35170)          LONGITUDE: 157° 48.7' W (-157.81200)


The bench mark is a disk set on top of a flat boulder lying in a cut between the
cliff face and an east-west running rock outcrop, 250 m (820 ft) SE (160 degrees
magnetic) from bench mark 8779  A 1996, 56 m (184 ft) NW (336 degrees magnetic)
from 8779 C 1996, 0.50 m (1.6 ft) from a cliff face and immediately south of a
small stream, and 0.34 m (1.1 ft) above southern end of cobble beach.

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

                                                                                
Station ID: 9458779                         PUBLICATION DATE:  04/29/2004
Name:       NAKCHAMIK ISLAND, PACIFIC OCEAN                   
            AK
NOAA Chart: 16566                           Latitude:   56° 21.1' N (  56.35170)
USGS Quad:  SUTWIK ISLAND (B-6)             Longitude: 157° 48.7' W (-157.81200)


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


                         BENCH MARK STAMPING:  8779 C 1996
                         DESIGNATION:          945 8779 C

MONUMENTATION:           Tidal Station disk                    VM#:        13148
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Rock outcrop                          OPUS PID:        
LATITUDE:   56° 21.1' N (  56.35170)          LONGITUDE: 157° 48.7' W (-157.81200)


The bench mark is a disk set at the base of a rock cliff, 56 m (184 ft) SE (156
degrees magnetic) from bench mark 8779 B 1996, 40 m (131 ft) NW (330 degrees
magnetic) from bench mark 8779 D 1996, and 0.50 m (1.6 ft) above the sand and
cobble beach.



                         BENCH MARK STAMPING:  8779 D 1996
                         DESIGNATION:          945 8779 D

MONUMENTATION:           Tidal Station disk                    VM#:        13149
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Boulder                               OPUS PID:        
LATITUDE:   56° 21.1' N (  56.35170)          LONGITUDE: 157° 48.7' W (-157.81200)


The bench mark is a disk set on top of a boulder embedded in a sand and cobble
beach at the base of a slide area, 40 m (131 ft) SE (150 degrees magnetic) from
bench mark 8779 C 1996, 34 m (112 ft) NW (328 degrees magnetic) from bench mark
8779 E 1996, and 5 m (16 ft) east of a cliff face.

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

                                                                                
Station ID: 9458779                         PUBLICATION DATE:  04/29/2004
Name:       NAKCHAMIK ISLAND, PACIFIC OCEAN                   
            AK
NOAA Chart: 16566                           Latitude:   56° 21.1' N (  56.35170)
USGS Quad:  SUTWIK ISLAND (B-6)             Longitude: 157° 48.7' W (-157.81200)


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


                         BENCH MARK STAMPING:  8779 E 1996
                         DESIGNATION:          945 8779 E

MONUMENTATION:           Tidal Station disk                    VM#:        13150
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Boulder                               OPUS PID:        
LATITUDE:   56° 21.1' N (  56.35170)          LONGITUDE: 157° 48.7' W (-157.81200)


The bench mark is a disk set on top of a boulder, 34 m (112 ft) SE (148 degrees
magnetic) from bench mark 8779 D 1996, 0.80 m (2.6 ft) east of an overhanging
cliff face, and 0.10 m (0.3 ft) above a sand and cobble beach.

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

                                                                                
Station ID: 9458779                         PUBLICATION DATE:  04/29/2004
Name:       NAKCHAMIK ISLAND, PACIFIC OCEAN                   
            AK
NOAA Chart: 16566                           Latitude:   56° 21.1' N (  56.35170)
USGS Quad:  SUTWIK ISLAND (B-6)             Longitude: 157° 48.7' W (-157.81200)


                            T I D A L   D A T U M S 


Tidal datums at NAKCHAMIK ISLAND, PACIFIC OCEAN based on:

     LENGTH OF SERIES:      2 MONTHS
     TIME PERIOD:           June 1996 - July 1996
     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   =  2.741
     MEAN HIGH WATER                            MHW    =  2.495
     MEAN TIDE LEVEL                            MTL    =  1.469
     MEAN SEA LEVEL                             MSL    =  1.444
     MEAN LOW WATER                             MLW    =  0.444
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     8779 A 1996                                 4.763    2.267
     8779 B 1996                                 3.313    0.817
     8779 C 1996                                 5.251    2.755
     8779 D 1996                                 4.988    2.493
     8779 E 1996                                 4.604    2.108


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

                                                                                
Station ID: 9458779                         PUBLICATION DATE:  04/29/2004
Name:       NAKCHAMIK ISLAND, PACIFIC OCEAN                   
            AK
NOAA Chart: 16566                           Latitude:   56° 21.1' N (  56.35170)
USGS Quad:  SUTWIK ISLAND (B-6)             Longitude: 157° 48.7' W (-157.81200)


                             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 9458779 NAKCHAMIK ISLAND, CHIGNIK BAY, AK

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