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Bench Mark Sheet for 9439008, FORT STEVENS OR

Superseded Epoch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Small blue map location marker Unpublished bench mark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: 9439008                         PUBLICATION DATE:  01/23/2004
Name:       FORT STEVENS                                      
            OR
NOAA Chart: 18521                           Latitude:   46° 12.4' N (  46.20670)
USGS Quad:  WARRENTON                       Longitude: 123° 57.0' W (-123.95000)


To reach the tidal bench marks from Astoria, take U.S. Highway 101/26 south
across Youngs Bay, turn right at the first intersection after crossing the bay
onto State Route 105 and follow it to Warrenton, turn right onto State Route 104
and follow the signs to Fort Stevens, turn right on Lake Drive (in Hammond) and
follow it for 1.21 km (0.75 mi) to the end of the road and the Columbia River
Bar Pilots Association Pier.  The bench marks are located in the vicinity of the
pier and on Fort Stevens Military Reservation.  The tide staff and gage were
located on the west side of the pier.


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


                 PRIMARY BENCH MARK STAMPING:  9008 A 1981
                         DESIGNATION:          943 9008 A TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:        11264
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Concrete piling                       OPUS PID:        
LATITUDE:   46° 12.4' N (  46.20670)          LONGITUDE: 123° 57.0' W (-123.95000)


The primary bench mark is a disk set flush in the east end of a 0.52 m (1.7 ft)
x 3.35 m ( 11 ft) concrete piling located at the foot of the Columbia River Bar
Pilots Association Pier, 9.24 m (30.3 ft) NNW of a telephone pole, and 5.88 m
(19.3 ft) south of the SE corner of a second concrete piling.

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

                                                                                
Station ID: 9439008                         PUBLICATION DATE:  01/23/2004
Name:       FORT STEVENS                                      
            OR
NOAA Chart: 18521                           Latitude:   46° 12.4' N (  46.20670)
USGS Quad:  WARRENTON                       Longitude: 123° 57.0' W (-123.95000)


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


                         BENCH MARK STAMPING:  USBM 3 1940
                         DESIGNATION:          943 9008 TIDAL 3

MONUMENTATION:           Tidal Station disk                    VM#:        11263
AGENCY:                  US Coast & Geodetic Survey
                         (USC&GS)                                 IDB PID#:  SC0586
SETTING CLASSIFICATION:  Manhole foundation                    OPUS PID:        
LATITUDE:   46° 12.4' N (  46.20670)          LONGITUDE: 123° 57.3' W (-123.95500)


The bench mark is a disk set in the top and at the NW corner of a concrete basin
of an old manhole located north of the centerline of the entrance road, 46 m
(150 ft) west of the entrance gate to Fort Stevens Historic Army Coast Artillery
Base site, 13.75 m (45.1 ft) SSE of the SW corner of "Search Light Generator
Shack", and 10.21 m (33.5 ft) south of the SE corner of the generator shack.

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

                                                                                
Station ID: 9439008                         PUBLICATION DATE:  01/23/2004
Name:       FORT STEVENS                                      
            OR
NOAA Chart: 18521                           Latitude:   46° 12.4' N (  46.20670)
USGS Quad:  WARRENTON                       Longitude: 123° 57.0' W (-123.95000)


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


                         BENCH MARK STAMPING:  GUN
                         DESIGNATION:          GUN RESET

MONUMENTATION:           Survey disk                           VM#:        11266
AGENCY:                  US Corp of Engineers (USE)            IDB PID#:  SC0583
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   46° 12.4' N (  46.20670)          LONGITUDE: 123° 57.7' W (-123.96200)


The bench mark is a disk set in the top of a concrete monument is located next
to a flagpole at the center of an earthen fort.



                         BENCH MARK STAMPING:  USGS BM
                         DESIGNATION:          943 9008 USGS BM

MONUMENTATION:           Nail                                  VM#:        11267
AGENCY:                  US Geological Survey (USGS)           IDB PID#:        
SETTING CLASSIFICATION:  Concrete manhole                      OPUS PID:        
LATITUDE:   46° 12.4' N (  46.20670)          LONGITUDE: 123° 57.0' W (-123.95000)


The bench mark is a nail set in the SW corner of a concrete manhole located near
the entrance road to Fort Stevens Historic Army Coast Artillery Base site, 146 m
(480 ft)  west of the main entrance gate, 26.55 m (87.1 ft) east of a sign
designating the site, 17.34 m (56.9 ft) ESE of the center of the gate leading to
the site, and 2 m (5 ft) north of the entrance road to the site.

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

                                                                                
Station ID: 9439008                         PUBLICATION DATE:  01/23/2004
Name:       FORT STEVENS                                      
            OR
NOAA Chart: 18521                           Latitude:   46° 12.4' N (  46.20670)
USGS Quad:  WARRENTON                       Longitude: 123° 57.0' W (-123.95000)


                            T I D A L   D A T U M S 


Tidal datums at FORT STEVENS based on:

     LENGTH OF SERIES:      7 MONTHS
     TIME PERIOD:           May 1981 - November 1981
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  9439040 ASTORIA, TONGUE POINT, COLUMBIA RIVER


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

     MEAN HIGHER HIGH WATER                     MHHW   =  2.624
     MEAN HIGH WATER                            MHW    =  2.410
     MEAN TIDE LEVEL                            MTL    =  1.401
     MEAN SEA LEVEL                             MSL    =  1.385
     MEAN LOW WATER                             MLW    =  0.391
     North American Vertical Datum              NAVD88 =  0.054
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     9008 A 1981                                 3.204    0.794
     USBM 3 1940                                 3.324    0.914
     GUN                                         5.667    3.257
     USGS BM                                     4.317    1.907


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

                                                                                
Station ID: 9439008                         PUBLICATION DATE:  01/23/2004
Name:       FORT STEVENS                                      
            OR
NOAA Chart: 18521                           Latitude:   46° 12.4' N (  46.20670)
USGS Quad:  WARRENTON                       Longitude: 123° 57.0' W (-123.95000)


                             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 9439008 FORT STEVENS, OR

Revised: 08/08/2018
NOAA / National Ocean Service
Web site owner: Center for Operational Oceanographic Products and Services