NOAA Web Site Link Tides and Currents Home Page Transparent placeholder image

Bench Mark Sheet for 9440581, Cape Disappointment

Superseded Epoch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Small blue map location marker Unpublished bench mark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: 9440581                         PUBLICATION DATE:  03/24/2016
Name:       CAPE DISAPPOINTMENT                               
            WA
NOAA Chart: 18521                           Latitude:   46° 18.0' N (  46.29997)
USGS Quad:  Cape Disappointment             Longitude: 124°  0.0' W (-124.00000)


From Longview, WA, cross the Lewis & Clark Bridge (WA 433) into Oregon and turn
west (right) on OR 30.  Proceed 47 miles to Astoria, OR and turn north (right)
onto US 101 and cross the bridge into Washington, then turn left to continue
north on US 101, 10 miles to Ilwaco. Turn left on Second Ave (WA 100 Spur) 1.7
miles to intersection with Ft. Canby Road.  Turn left on Ft. Canby 0.6 miles to
left turn onto Coast Guard Road. You will need to use call box at gate to gain
entrance to base. Once through gate continue 0.35 miles on Coast Guard Rd to
boat houses and dock on the left. The tide station is located inside the first
boathouse and the benchmarks are located along Coast Guard Road.


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


                 PRIMARY BENCH MARK STAMPING:  0581 C 2015
                         DESIGNATION:          944 0581 C

MONUMENTATION:           Flange-encased Rod                    VM#:        21625
AGENCY:                                                        IDB PID#:        
SETTING CLASSIFICATION:                                        OPUS PID#: BBDX15
LATITUDE:   46° 16.8' N (  46.28067)          LONGITUDE: 124°  2.8' W (-124.04681)


The primary bench mark is a 9/16 inch (14 mm) stainless steel rod driven 2.1 (7
ft) to refusal on the N side of Coast Guard Road on USCG Cape Disappointment
station, located 3.7 m (12.1 ft) S of a NOAA witness post, 3.55 m (11.6 ft) N of
N edge of Coast Guard road, 2.98 m (9.8 ft) W of W side of weapon unloading
station.

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

                                                                                
Station ID: 9440581                         PUBLICATION DATE:  03/24/2016
Name:       CAPE DISAPPOINTMENT                               
            WA
NOAA Chart: 18521                           Latitude:   46° 18.0' N (  46.29997)
USGS Quad:  Cape Disappointment             Longitude: 124°  0.0' W (-124.00000)


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


                         BENCH MARK STAMPING:  0581 A 2015
                         DESIGNATION:          944 0581 A

MONUMENTATION:           Bench Mark disk                       VM#:        21626
AGENCY:                                                        IDB PID#:        
SETTING CLASSIFICATION:  Concrete manhole                      OPUS PID:        
LATITUDE:   46° 16.8' N (  46.27922)          LONGITUDE: 124°  2.9' W (-124.04831)


The bench mark is a brass NOS disk set flush in the W side of a 1.95 m (6.4 ft)
X 1.95 m (6.4 ft) concrete manhole structure on the E side of Coast Guard Road
on US Coast Guard Cape Disappointment base, located 3.71 m (12.2 ft) E of
centerline of Coast Guard Road, 2.95 m (9.7 ft) N of National Motor Life Boat
school sign, 0.75 m (2.5 ft) NW of center of manhole, and 0.2 m (0.7 ft) above
ground level.



                         BENCH MARK STAMPING:  0581 B 2015
                         DESIGNATION:          944 0581 B

MONUMENTATION:           Flange-encased Rod                    VM#:        21627
AGENCY:                                                        IDB PID#:        
SETTING CLASSIFICATION:                                        OPUS PID:        
LATITUDE:   46° 16.8' N (  46.27975)          LONGITUDE: 124°  2.8' W (-124.04744)


The bench mark is a 9/16 inch (14 mm) stainless steel rod driven 8.2 m (27 ft)
to refusal on the W side of Coast Guard Road on US Coast Guard Cape
Disappointment station, located 5.86 m (19.2 ft) S of south end of rock slide
protection fence, 1.66 m (5.4 ft) E of NOAA witness post, 1.30 m (4.3 ft) W of W
edge of pavement.

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

                                                                                
Station ID: 9440581                         PUBLICATION DATE:  03/24/2016
Name:       CAPE DISAPPOINTMENT                               
            WA
NOAA Chart: 18521                           Latitude:   46° 18.0' N (  46.29997)
USGS Quad:  Cape Disappointment             Longitude: 124°  0.0' W (-124.00000)


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


                         BENCH MARK STAMPING:  0581 E 2015
                         DESIGNATION:          944 0581 E

MONUMENTATION:           Flange-encased Rod                    VM#:        21628
AGENCY:                                                        IDB PID#:        
SETTING CLASSIFICATION:                                        OPUS PID:        
LATITUDE:   46° 16.8' N (  46.27928)          LONGITUDE: 124°  2.7' W (-124.04522)


The bench mark is a 9/16 inch (14 mm) stainless steel rod driven 1.2 m (4 ft) to
refusal at the end of Coast Guard road on USCG Cape Disappointment station,
located 5.2 m (17.1 ft) SE of the S end of the landslide protection fence, 3.7 m
(12.1 ft) NE of a 2 m (6.6 ft) x 3 m (9.8 ft) boulder, 2 m (6.6 ft) S of the S
corner of a concrete electric vault.



                         BENCH MARK STAMPING:  0581 D 2015
                         DESIGNATION:          944 0581 D

MONUMENTATION:           Bench Mark disk                       VM#:        21629
AGENCY:                                                        IDB PID#:        
SETTING CLASSIFICATION:  Concrete slab                         OPUS PID:        
LATITUDE:   46° 16.8' N (  46.28022)          LONGITUDE: 124°  2.7' W (-124.04528)


The bench mark is a brass NOS disk set flush in the concrete foundation of the
roll up door at the entrance to the US Coast Guard boat repair building numbered
71718 and 12741, located 21.2 m (69.6 ft) SSE from center of boatlift, 7.7 m
(25.3 ft) E from W corner of roll up door of US Coast Guard boat repair
building, 0.3 m (1.0 ft) W from E corner of roll up door of US Coast Guard
repair building.

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

                                                                                
Station ID: 9440581                         PUBLICATION DATE:  03/24/2016
Name:       CAPE DISAPPOINTMENT                               
            WA
NOAA Chart: 18521                           Latitude:   46° 18.0' N (  46.29997)
USGS Quad:  Cape Disappointment             Longitude: 124°  0.0' W (-124.00000)


                            T I D A L   D A T U M S 


Tidal datums at CAPE DISAPPOINTMENT based on:

     LENGTH OF SERIES:      1 MONTH
     TIME PERIOD:           August 2015 - August 2015
     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   =  2.364
     MEAN HIGH WATER                            MHW    =  2.159
     MEAN TIDE LEVEL                            MTL    =  1.264
     MEAN SEA LEVEL                             MSL    =  1.232
     MEAN LOW WATER                             MLW    =  0.369
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     0581 C 2015                                 3.975    1.816
     0581 A 2015                                 5.742    3.583
     0581 B 2015                                 4.988    2.829
     0581 E 2015                                 5.298    3.139
     0581 D 2015                                 4.801    2.642


Foot Notes:

 Bench marks 0581 D 2015 and 0581 E 2015 are based on one differential leveling
connection and do not meet the quality control standards of the NOS. Therefore,
caution should be used when deriving elevations for these marks. 

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

                                                                                
Station ID: 9440581                         PUBLICATION DATE:  03/24/2016
Name:       CAPE DISAPPOINTMENT                               
            WA
NOAA Chart: 18521                           Latitude:   46° 18.0' N (  46.29997)
USGS Quad:  Cape Disappointment             Longitude: 124°  0.0' W (-124.00000)


                             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.

Return to Top
Products available at 9440581 Cape Disappointment,

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