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Bench Mark Sheet for 9452067, HOLKHAM BAY, STEPHENS PASSAGE 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Superseded Epoch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Small blue map location marker Unpublished bench mark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: 9452067                         PUBLICATION DATE:  06/18/2014
Name:       HOLKHAM BAY, STEPHENS PASSAGE                     
            AK
NOAA Chart: 17300                           Latitude:   57° 45.6' N (  57.76000)
USGS Quad:  SUMDUM (D-5)                    Longitude: 133° 36.2' W (-133.60300)


To reach tidal bench marks from SE Alaska, go to Holkam Bay at the entrance of
Tracy and Endicott Arms, then 0.4 km (0.3 mi) east of Harbor Island, and then go
0.6 km (0.4 mi) north of Rond Inlet.  The bench marks and tide gage were located
on the easterly point of the small unnamed island.


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


                 PRIMARY BENCH MARK STAMPING:  TIDAL 1 1973
                         DESIGNATION:          945 2067 TIDAL 1

MONUMENTATION:           Tidal Station disk                    VM#:        13682
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Rock outcrop                          OPUS PID:        
LATITUDE:   57° 45.6' N (  57.76000)          LONGITUDE: 133° 36.2' W (-133.60300)


The primary bench mark is a disk set in rock outcrop, 0.76 m (2.5 ft) north of
bench mark Tidal 2 1973, about 1 m (2 ft) west of the apparent high water line,
and 1 m (2 ft) above the apparent high water line.



                         BENCH MARK STAMPING:  TIDAL 2 1973
                         DESIGNATION:          945 2067 TIDAL 2

MONUMENTATION:           Tidal Station disk                    VM#:        13683
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Rock outcrop                          OPUS PID:        
LATITUDE:   57° 45.6' N (  57.76000)          LONGITUDE: 133° 36.2' W (-133.60300)


The bench mark is a disk set in rock outcrop, 12 m (41 ft) north of bench mark
Tidal 3 1973, 3 m (10 ft) west of the apparent high water line, and 1 m (2 ft)
above the apparent high water line.

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

                                                                                
Station ID: 9452067                         PUBLICATION DATE:  06/18/2014
Name:       HOLKHAM BAY, STEPHENS PASSAGE                     
            AK
NOAA Chart: 17300                           Latitude:   57° 45.6' N (  57.76000)
USGS Quad:  SUMDUM (D-5)                    Longitude: 133° 36.2' W (-133.60300)


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


                         BENCH MARK STAMPING:  TIDAL 3 1973
                         DESIGNATION:          945 2067 TIDAL 3

MONUMENTATION:           Tidal Station disk                    VM#:        13684
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Rock outcrop                          OPUS PID:        
LATITUDE:   57° 45.6' N (  57.76000)          LONGITUDE: 133° 36.2' W (-133.60300)


The bench mark is a disk set in rock outcrop, 12 m (40 ft) NE of bench mark
Tidal 4 1973, 1 m (3 ft) west of the apparent high water line, and 1 m (4 ft)
above the apparent high water line.



                         BENCH MARK STAMPING:  TIDAL 4 1973
                         DESIGNATION:          945 2067 TIDAL 4

MONUMENTATION:           Tidal Station disk                    VM#:        13685
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Rock outcrop                          OPUS PID:        
LATITUDE:   57° 45.6' N (  57.76000)          LONGITUDE: 133° 36.2' W (-133.60300)


The bench mark is a disk set in rock outcrop, 9 m (28 ft) east of bench mark
Tidal 5 1973, 1 m (4 ft) north of the apparent high water line, and 1 m (3 ft)
above the apparent high water line.

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

                                                                                
Station ID: 9452067                         PUBLICATION DATE:  06/18/2014
Name:       HOLKHAM BAY, STEPHENS PASSAGE                     
            AK
NOAA Chart: 17300                           Latitude:   57° 45.6' N (  57.76000)
USGS Quad:  SUMDUM (D-5)                    Longitude: 133° 36.2' W (-133.60300)


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


                         BENCH MARK STAMPING:  TIDAL 5 1973
                         DESIGNATION:          945 2067 TIDAL 5

MONUMENTATION:           Tidal Station disk                    VM#:        13686
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Rock outcrop                          OPUS PID:        
LATITUDE:   57° 45.6' N (  57.76000)          LONGITUDE: 133° 36.2' W (-133.60300)


The bench mark is a disk set in rock outcrop, 1 m (2 ft) north of the apparent
high water line, and 0.46 m (1.5 ft) above the apparent high water line.

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

                                                                                
Station ID: 9452067                         PUBLICATION DATE:  06/18/2014
Name:       HOLKHAM BAY, STEPHENS PASSAGE                     
            AK
NOAA Chart: 17300                           Latitude:   57° 45.6' N (  57.76000)
USGS Quad:  SUMDUM (D-5)                    Longitude: 133° 36.2' W (-133.60300)


                            T I D A L   D A T U M S 


Tidal datums at HOLKHAM BAY, STEPHENS PASSAGE based on:

     LENGTH OF SERIES:      30 DAYS
     TIME PERIOD:           MAY 25, 1997 thru JUNE 23, 1997
     TIDAL EPOCH:           2007-2011
     CONTROL TIDE STATION:  9452210 JUNEAU, GASTINEAU CHANNEL, STEPHENS PASS


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

     MEAN HIGHER HIGH WATER                     MHHW   =  4.758
     MEAN HIGH WATER                            MHW    =  4.476
     MEAN SEA LEVEL                             MSL    =  2.502
     MEAN TIDE LEVEL                            MTL    =  2.473
     MEAN LOW WATER                             MLW    =  0.470
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     TIDAL 1 1973                                5.562    1.087
     TIDAL 2 1973                                6.358    1.883
     TIDAL 3 1973                                5.599    1.123
     TIDAL 4 1973                                5.707    1.231
     TIDAL 5 1973                                5.553    1.077


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

                                                                                
Station ID: 9452067                         PUBLICATION DATE:  06/18/2014
Name:       HOLKHAM BAY, STEPHENS PASSAGE                     
            AK
NOAA Chart: 17300                           Latitude:   57° 45.6' N (  57.76000)
USGS Quad:  SUMDUM (D-5)                    Longitude: 133° 36.2' W (-133.60300)


                             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 9452067 HOLKHAM BAY, STEPHENS PASSAGE, AK

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