U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 6
Station ID: 9440482 PUBLICATION DATE: 01/12/2017
Name: CAPE HORN, COLUMBIA RIVER
WA
NOAA Chart: 18523 Latitude: 46° 9.1' N ( 46.15170)
USGS Quad: NASSA POINT Longitude: 123° 17.4' W (-123.29000)
To reach the tidal bench marks from the intersection of main street and
Washington State Highway 4 in Cathlamat, proceed east on state highway 4 for
10.8 km (6.7 mi) to the intersection with Wallen way. Turn right and proceed
south on Wallen way for 250 m (820.2 ft) to the private residence at 11 Wallen
way. The bench marks are located in the lawn area between the residence and the
Columbia river, up a private drive way to State Highway 4, and from the driveway
exit to the west along State Highway 4. The tide gauge is located on the
southeast piling of a floating boat dock.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 0482 A 2016
DESIGNATION: 944 0482 A
MONUMENTATION: Flange-encased Rod VM#: 22071
AGENCY: National Ocean Service IDB PID#:
SETTING CLASSIFICATION: OPUS PID#: BBFG94
LATITUDE: 46° 9.2' N ( 46.15250) LONGITUDE: 123° 16.3' W (-123.27158)
The bench mark is a flange encased rod set to the east of the private boat
launch area at the residence of 11 Wallen Way, 49.15 m (161.3 ft) SE of the SE
corner of the pool building, 46.05 m (151.1 ft) SSE of the SE building corner of
the main residence, 32.50 m (106.6 ft) SSW of the SW post of the garage, 13.60 m
(44.6 ft) SSE of the edge of pavement and 10.95 m (35.9 ft) NNW of the top of
the river bank. The datum point is set 11 cm (4 inches) below ground, being the
top of a stainless steel rod driven 15.0 m (49.2 ft) to refusal, in a sleeve
extending to a depth of 1.1 m (3.6 ft) and encased in a 7-inch NOS logo cap.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 6
Station ID: 9440482 PUBLICATION DATE: 01/12/2017
Name: CAPE HORN, COLUMBIA RIVER
WA
NOAA Chart: 18523 Latitude: 46° 9.1' N ( 46.15170)
USGS Quad: NASSA POINT Longitude: 123° 17.4' W (-123.29000)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 0482 B 2016
DESIGNATION: 944 0482 B
MONUMENTATION: Bench Mark disk VM#: 22072
AGENCY: National Ocean Service IDB PID#:
SETTING CLASSIFICATION: Concrete retaining wall OPUS PID:
LATITUDE: 46° 9.2' N ( 46.15283) LONGITUDE: 123° 16.3' W (-123.27217)
The bench mark is a disk set on the north end of a concrete retaining wall on
the residence of 11 Wallen way, 13.85 m (45.4 ft) NNW of the SW corner of the
retaining wall, 9.88 m (32.4 ft) north of the center of a storm drain, 3.55 m
(11.6 ft) south of the NW pool building corner, 3.51 m (11.5 ft) SSE of center
of an electrical box, 0.35 m (1.1 ft) SE of the NW corner of the retaining wall,
and 12 cm (5 inches) above the driveway level.
BENCH MARK STAMPING: 0482 C 2016
DESIGNATION: 944 0482 C
MONUMENTATION: Bench Mark disk VM#: 22073
AGENCY: National Ocean Service IDB PID#:
SETTING CLASSIFICATION: Concrete light pole base OPUS PID:
LATITUDE: 46° 9.2' N ( 46.15386) LONGITUDE: 123° 16.1' W (-123.26822)
The bench mark is a disk set in a footing for an overhead sign on the south side
of a private driveway, 26.20 m (86.0 ft) SW of the east end of a guardrail,
15.69 m (51.5 ft) SW of the west end of a guardrail, 4.45 m (14.6 ft) ENE of the
east face of a 0.75 m (2.5 ft) diameter fir tree, 1.37 m (4.5 ft) south of the
edge pavement, 0.73 m (2.4 ft) north of the sign support pole, 0.56 m (1.8 ft)
south of the north edge of the concrete footing, and 0.16 m (0.5 ft) above the
grade on the north side of the footing.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 6
Station ID: 9440482 PUBLICATION DATE: 01/12/2017
Name: CAPE HORN, COLUMBIA RIVER
WA
NOAA Chart: 18523 Latitude: 46° 9.1' N ( 46.15170)
USGS Quad: NASSA POINT Longitude: 123° 17.4' W (-123.29000)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 0482 D 2016
DESIGNATION: 944 0482 D
MONUMENTATION: Bench Mark disk VM#: 22074
AGENCY: National Ocean Service IDB PID#:
SETTING CLASSIFICATION: OPUS PID:
LATITUDE: 46° 9.2' N ( 46.15350) LONGITUDE: 123° 16.6' W (-123.27689)
The bench mark is a disk set in bedrock about 100 m (328.1 ft) west of a gravel
pullout on state highway 4, 29.35 m (96.3 ft) west of a power pole marked 912010
4140, 14.10 m (46.3 ft) north of the edge of a guard rail, 10.20 m (33.5 ft)
north of the centerline of the highway, 10.10 m (33.1 ft) ESE of a 0.76 m (2.5
ft) diameter fir tree, 6.15 m (20.2 ft) north of the edge of pavement and 1.0 m
(3.3 ft) above grade.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 6
Station ID: 9440482 PUBLICATION DATE: 01/12/2017
Name: CAPE HORN, COLUMBIA RIVER
WA
NOAA Chart: 18523 Latitude: 46° 9.1' N ( 46.15170)
USGS Quad: NASSA POINT Longitude: 123° 17.4' W (-123.29000)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: Q 202 1941
DESIGNATION: Q 202
MONUMENTATION: Survey disk VM#: 22075
AGENCY: National Ocean Service IDB PID#: SC0312
SETTING CLASSIFICATION: OPUS PID:
LATITUDE: 46° 9.2' N ( 46.15272) LONGITUDE: 123° 16.8' W (-123.28064)
The bench mark is a disk set in a concrete monument on the south side of WA
state highway 4, 20.50 m (67.3 ft) SSW of a power pole, 10.5 m (34.4 ft) ENE of
the face of an 0.84 m (2.8 ft) diameter fir tree, 8.40 m (27.6 ft) NNW of the
centerline of the highway, 4.09 m (13.4 ft) NNW of the edge of the pavement,
0.42 m (1.4 ft) north of a metal survey marker sign and 0.26 m (0.9 ft) above
grade.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 6
Station ID: 9440482 PUBLICATION DATE: 01/12/2017
Name: CAPE HORN, COLUMBIA RIVER
WA
NOAA Chart: 18523 Latitude: 46° 9.1' N ( 46.15170)
USGS Quad: NASSA POINT Longitude: 123° 17.4' W (-123.29000)
T I D A L D A T U M S
Tidal datums at CAPE HORN, COLUMBIA RIVER based on:
LENGTH OF SERIES: 3 MONTHS
TIME PERIOD: August 2016 - October 2016
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 = 1.937
MEAN HIGH WATER MHW = 1.761
MEAN TIDE LEVEL MTL = 0.970
MEAN SEA LEVEL MSL = 0.911
MEAN LOW WATER MLW = 0.178
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
0482 A 2016 3.985 2.224
0482 B 2016 4.271 2.510
0482 C 2016 32.572 30.811
0482 D 2016 60.168 58.407
Q 202 1941 72.529 70.768
Foot Notes:
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 6
Station ID: 9440482 PUBLICATION DATE: 01/12/2017
Name: CAPE HORN, COLUMBIA RIVER
WA
NOAA Chart: 18523 Latitude: 46° 9.1' N ( 46.15170)
USGS Quad: NASSA POINT Longitude: 123° 17.4' W (-123.29000)
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.