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Bench Mark Sheet for 9452249, YOUNG 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Superseded Epoch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Small blue map location marker Unpublished bench mark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: 9452249                         PUBLICATION DATE:  06/21/2018
Name:       YOUNG BAY                                         
            AK
NOAA Chart: 17315                           Latitude:   58° 11.0' N (  58.18330)
USGS Quad:  JUNEAU (A-2)                    Longitude: 134° 35.2' W (-134.58700)


To reach tidal bench marks, from Juneau proceed to eastern Young Bay and then
proceed south to Admiralty Cove to the northeastern end of the island at
Latitude 58 11.04' N, Longitude 134 35.22' W.  The island is connected to
Admiralty Island at low water.  The tide gage and bench marks were located along
the beach in the general vicinity.


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


                 PRIMARY BENCH MARK STAMPING:  2249 A 1997
                         DESIGNATION:          945 2249 A

MONUMENTATION:           Tidal Station disk                    VM#:        13665
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Bedrock                               OPUS PID:        
LATITUDE:   58° 11.0' N (  58.18400)          LONGITUDE: 134° 35.2' W (-134.58700)


The primary bench mark is a disk set on a rocky outcrop of bedrock, 30 m (98 ft)
NW (330 degrees magnetic) from bench mark 2249 B 1997, and 2 m (5 ft) above the
apparent high water line.



                         BENCH MARK STAMPING:  2249 B 1997
                         DESIGNATION:          945 2249 B

MONUMENTATION:           Tidal Station disk                    VM#:        13666
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Bedrock                               OPUS PID:        
LATITUDE:   58° 11.0' N (  58.18400)          LONGITUDE: 134° 35.2' W (-134.58700)


The bench mark is a disk set on a rocky outcrop of bedrock, 30 m (98 ft) SE (150
degrees magnetic) from bench mark 2249 A 1997, 35 m (115 ft) NE (010 degrees
magnetic) from bench mark 2249 C 1997, and 2 m (5 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: 9452249                         PUBLICATION DATE:  06/21/2018
Name:       YOUNG BAY                                         
            AK
NOAA Chart: 17315                           Latitude:   58° 11.0' N (  58.18330)
USGS Quad:  JUNEAU (A-2)                    Longitude: 134° 35.2' W (-134.58700)


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


                         BENCH MARK STAMPING:  2249 C 1997
                         DESIGNATION:          945 2249 C

MONUMENTATION:           Tidal Station disk                    VM#:        13667
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Granite boulder                       OPUS PID:        
LATITUDE:   58° 11.0' N (  58.18400)          LONGITUDE: 134° 35.2' W (-134.58700)


The bench mark is a disk set on a granite boulder situated at the treeline, 35 m
(115 ft) SW (190 degrees magnetic) from bench mark 2249 B 1997,  55 m (180 ft)
NW (285 degrees magnetic) from bench mark 2249 D 1997, and 2 m (5 ft) above the
apparent high water line.



                         BENCH MARK STAMPING:  2249 D 1997
                         DESIGNATION:          945 2249 D

MONUMENTATION:           Tidal Station disk                    VM#:        13670
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Bedrock                               OPUS PID:        
LATITUDE:   58° 11.0' N (  58.18400)          LONGITUDE: 134° 35.2' W (-134.58700)


The bench mark is a disk set in bedrock, 55 m (180 ft) SE (105 degrees magnetic)
from bench mark 2249 C 1997,  50 m (164 ft) NW (275 degrees magnetic) from bench
mark 2249 E 1997, and 2 m (5 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: 9452249                         PUBLICATION DATE:  06/21/2018
Name:       YOUNG BAY                                         
            AK
NOAA Chart: 17315                           Latitude:   58° 11.0' N (  58.18330)
USGS Quad:  JUNEAU (A-2)                    Longitude: 134° 35.2' W (-134.58700)


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


                         BENCH MARK STAMPING:  2249 E 1997
                         DESIGNATION:          945 2249 E

MONUMENTATION:           Tidal Station disk                    VM#:        13672
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Bedrock                               OPUS PID:        
LATITUDE:   58° 11.0' N (  58.18400)          LONGITUDE: 134° 35.2' W (-134.58700)


The bench mark is a disk set in bedrock protruding from a gently sloping rocky
beach, 50 m (164 ft) SE (95 degrees magnetic) from bench mark 2249 D 1997, and 2
m (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: 9452249                         PUBLICATION DATE:  06/21/2018
Name:       YOUNG BAY                                         
            AK
NOAA Chart: 17315                           Latitude:   58° 11.0' N (  58.18330)
USGS Quad:  JUNEAU (A-2)                    Longitude: 134° 35.2' W (-134.58700)


                            T I D A L   D A T U M S 


Tidal datums at YOUNG BAY based on:

     LENGTH OF SERIES:      30 DAYS
     TIME PERIOD:           Apr  1 1997 - Apr 30 1997
     TIDAL EPOCH:           2012-2016
     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   =  4.996
     MEAN HIGH WATER                            MHW    =  4.689
     MEAN SEA LEVEL                             MSL    =  2.627
     MEAN TIDE LEVEL                            MTL    =  2.588
     MEAN LOW WATER                             MLW    =  0.486
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     2249 A 1997                                 7.185    2.496
     2249 B 1997                                 7.014    2.325
     2249 C 1997                                 7.113    2.424
     2249 D 1997                                 5.384    0.695
     2249 E 1997                                 6.210    1.521


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

                                                                                
Station ID: 9452249                         PUBLICATION DATE:  06/21/2018
Name:       YOUNG BAY                                         
            AK
NOAA Chart: 17315                           Latitude:   58° 11.0' N (  58.18330)
USGS Quad:  JUNEAU (A-2)                    Longitude: 134° 35.2' W (-134.58700)


                             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: 10/15/2013
NOAA / National Ocean Service
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