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Bench Mark Sheet for 9451204, Wrangell 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Superseded Epoch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Small blue map location marker Unpublished bench mark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.

Error: There is no bench mark map available for 9451204 Wrangell, AK
Printable version

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  5

                                                                                
Station ID: 9451204                         PUBLICATION DATE:  07/15/2004
Name:       WRANGELL, WRANGELL ISLAND                         
            AK
NOAA Chart: 17385                           Latitude:   56° 28.2' N (  56.47000)
USGS Quad:  PETERSBURG (B-1)                Longitude: 132° 23.2' W (-132.38700)


To reach the tidal bench marks from Ketchikan via boat, proceed NW along
Clarence Strait for approximately 139 km (75 nm) to Stikine Strait, then NE
along Stikine Strait for approximately 46 km (25 nm) to Wrangell on the northern
end of Wrangell Island.  The tidal bench marks are in the vicinity of the Post
Office, Front Street, and Presbyterian Parsonage.  The tide gage was located SE
from the city dock in a shed along the breakwater in a container yard in
Wrangell Harbor.  


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


                 PRIMARY BENCH MARK STAMPING:  NO 6 1954
                         DESIGNATION:          945 1204 TIDAL 6

MONUMENTATION:           Tidal Station disk                    VM#:        11800
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  TT8546
SETTING CLASSIFICATION:  Rock outcrop                          OPUS PID:        
LATITUDE:   ' °deg (0)          LONGITUDE:  ' °deg (0)


The primary bench mark is a disk set in the highest point of the north end of a
large rock outcrop between the Stikine Avenue and Front Street in front of the
Post Office, 34.56 m (113.4 ft) NW from bench mark 1204 A 2001, and 29.14 m
(95.6 ft) WSW of the SE corner of the Post Office.

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

                                                                                
Station ID: 9451204                         PUBLICATION DATE:  07/15/2004
Name:       WRANGELL, WRANGELL ISLAND                         
            AK
NOAA Chart: 17385                           Latitude:   56° 28.2' N (  56.47000)
USGS Quad:  PETERSBURG (B-1)                Longitude: 132° 23.2' W (-132.38700)


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


                         BENCH MARK STAMPING:  NO 9 1971
                         DESIGNATION:          945 1204 TIDAL 9

MONUMENTATION:           Tidal Station disk                    VM#:        11802
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Concrete steps                        OPUS PID:        
LATITUDE:   ' °deg (0)          LONGITUDE:  ' °deg (0)


The bench mark is a disk set in the top concrete step of the stairs leading to
the basement on the back side of the Post Office, NW of the NE corner of the
same building, 71.87 m (235.8 ft) NNW of bench mark 1204 A 2001, and 0.09 m (0.3
ft) NE of the NE wall of the Post Office building.



                         BENCH MARK STAMPING:   
                         DESIGNATION:          945 1204 BM 5
                         ALIAS:                5

MONUMENTATION:           Bench Mark disk                       VM#:        16496
AGENCY:                  Unknown                               IDB PID#:        
SETTING CLASSIFICATION:  Boulder                               OPUS PID#: BBDG97
LATITUDE:   ' °deg (0)          LONGITUDE:  ' °deg (0)


The bench mark is an unstamped brass disk set in a large white boulder 2 m x 1 m
x 1 m (5 ft x 3 ft x 3 ft) located in front of the Presbyterian parsonage, 15.42
m (50.6 ft) SW of the SW corner of the Parsonage, and 10.24 m (33.6 ft) north of
the center line of Church Street.

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

                                                                                
Station ID: 9451204                         PUBLICATION DATE:  07/15/2004
Name:       WRANGELL, WRANGELL ISLAND                         
            AK
NOAA Chart: 17385                           Latitude:   56° 28.2' N (  56.47000)
USGS Quad:  PETERSBURG (B-1)                Longitude: 132° 23.2' W (-132.38700)


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


                         BENCH MARK STAMPING:  1204 A 2001
                         DESIGNATION:          945 1204 A

MONUMENTATION:           Tidal Station disk                    VM#:        16497
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Concrete sidewalk                     OPUS PID:        
LATITUDE:   ' °deg (0)          LONGITUDE:  ' °deg (0)


The bench mark is a disk set in the concrete sidewalk on the corner of Stikine
Street and Front Street, 71.87 m (235.8 ft) SSW of bench mark NO 9 1971, 34.56 m
(113.4 ft) SE from the highest point of the north end of a large rock outcrop,
29.14 m (95.6 ft) WSW of the SE corner of the Post Office. 



                         BENCH MARK STAMPING:  1204 B 2001
                         DESIGNATION:          945 1204 B

MONUMENTATION:           Tidal Station disk                    VM#:        16498
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Concrete sidewalk                     OPUS PID:        
LATITUDE:   ' °deg (0)          LONGITUDE:  ' °deg (0)


The bench mark is a disk set in the concrete sidewalk on the west corner of
McKinnon and Front Street, 9 m (31 ft) west of the east side of McKinnon Street,
8 m (25 ft) from the center of intersection of McKinnon and Front Streets, and
0.53 m (1.7 ft) south from a stop sign located on the north side of the
intersection. 

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

                                                                                
Station ID: 9451204                         PUBLICATION DATE:  07/15/2004
Name:       WRANGELL, WRANGELL ISLAND                         
            AK
NOAA Chart: 17385                           Latitude:   56° 28.2' N (  56.47000)
USGS Quad:  PETERSBURG (B-1)                Longitude: 132° 23.2' W (-132.38700)


                            T I D A L   D A T U M S 


Tidal datums at WRANGELL, WRANGELL ISLAND based on:

     LENGTH OF SERIES:      2 MONTHS
     TIME PERIOD:           April 2001 - May 2001
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  9450460 KETCHIKAN, TONGASS NARROWS


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

     MEAN HIGHER HIGH WATER                     MHHW   =  4.864
     MEAN HIGH WATER                            MHW    =  4.595
     MEAN TIDE LEVEL                            MTL    =  2.528
     MEAN SEA LEVEL                             MSL    =  2.519
     MEAN LOW WATER                             MLW    =  0.460
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     NO 6 1954                                  12.275    7.680
     NO 9 1971                                  13.958    9.363
     945 1204 BM 5                              17.591   12.996
     1204 A 2001                                 7.802    3.207
     1204 B 2001                                 7.676    3.081


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

                                                                                
Station ID: 9451204                         PUBLICATION DATE:  07/15/2004
Name:       WRANGELL, WRANGELL ISLAND                         
            AK
NOAA Chart: 17385                           Latitude:   56° 28.2' N (  56.47000)
USGS Quad:  PETERSBURG (B-1)                Longitude: 132° 23.2' W (-132.38700)


                             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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Revised: 08/08/2018
NOAA / National Ocean Service
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