U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
PUBLICATION DATE: 08/12/1986
Station ID: 9432771 SUPERCEDED DATE: 04/21/2003
Name: CAPE ARAGO LIGHTHOUSE, PACIFIC OCEAN
OREGON
NOAA Chart: 18587 Latitude: 43° 20.5' N
USGS Quad: CAPE ARAGO Longitude: 124° 22.5' W
To reach the tidal bench marks from Charleston, proceed west on Cape Arago
Highway for 2.5 miles (4.0 km) toward Lighthouse Beach and Cape Arago. The
bench marks are located along the highway and foot bridge leading to the Cape
Arago Lighthouse. The tide gage and staff were located on the foot bridge.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: TIDAL 1 1972
MONUMENTATION: Survey Disk VM#: 8782
AGENCY: PID:
SETTING CLASSIFICATION: Bedrock
The bench mark is set flush in bedrock 390 feet (119 m) SW of Cape Arago
Lighthouse, 17 feet (5 m) east of the centerline of the foot bridge leading to
the lighthouse, 7 feet (2 m) south of the north end of a rocky outcrop at the
south edge of the channel, and 6 feet (2 m) east of the third concrete footing
from the south end of the bridge.
BENCH MARK STAMPING: H 286 1939 54.2
MONUMENTATION: Survey Disk VM#: 8781
AGENCY: PID#: OA0531
SETTING CLASSIFICATION: Concrete Monument
The bench mark is set flush in a concrete monument at the junction of Cape Arago
Highway and the road leading to Cape Arago Lighthouse, 33 feet (10 m) west of
the centerline of the highway, 18 feet (5 m) south of the road leading to the
lighthouse, 3 feet (1 m) south of a wooden witness post, and 0.2 foot (0.1 m)
above ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
PUBLICATION DATE: 08/12/1986
Station ID: 9432771 SUPERCEDED DATE: 04/21/2003
Name: CAPE ARAGO LIGHTHOUSE, PACIFIC OCEAN
OREGON
NOAA Chart: 18587 Latitude: 43° 20.5' N
USGS Quad: CAPE ARAGO Longitude: 124° 22.5' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: TIDAL 2 1972
MONUMENTATION: Survey Disk VM#: 8783
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Pier
The bench mark is set flush in an old concrete bridge pier under the foot
bridge, 3 feet (1 m) east of the centerline of the foot bridge, and 3 feet (1 m)
south of the second bridge pier foundation from the south end of the bridge.
BENCH MARK STAMPING: TIDAL 3 1972
MONUMENTATION: Survey Disk VM#: 8784
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Footing
The bench mark is set flush in the NE corner of the most southeastern concrete
pier footing of the foot bridge leading to the lighthouse, and 32 feet (10 m)
below the deck of the bridge.
BENCH MARK STAMPING: TIDAL 4 1972
MONUMENTATION: Survey Disk VM#: 8785
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Foundation
The bench mark is set flush in the east end of the most southern of two 1.2 x
14-foot (0.4 x 4 m) concrete foundations in an open grassy area, 79 feet (24 m)
west of the centerline of the road leading to the lighthouse, 54 feet (16 m)
north of the NE corner of the garage of the U.S. Coast Guard residences, and 0.5
foot (0.2 m) above ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
PUBLICATION DATE: 08/12/1986
Station ID: 9432771 SUPERCEDED DATE: 04/21/2003
Name: CAPE ARAGO LIGHTHOUSE, PACIFIC OCEAN
OREGON
NOAA Chart: 18587 Latitude: 43° 20.5' N
USGS Quad: CAPE ARAGO Longitude: 124° 22.5' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: TIDAL ARAGO 4 1976
MONUMENTATION: Survey Disk VM#: 8786
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Pad
The bench mark is set flush in the NE corner of a 5 x 9-foot (2 x 3 m) concrete
pad at the foot of the path leading to the foot bridge, and 9 feet (3 m) south
of the centerline of the road leading to the foot bridge.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
PUBLICATION DATE: 08/12/1986
Station ID: 9432771 SUPERCEDED DATE: 04/21/2003
Name: CAPE ARAGO LIGHTHOUSE, PACIFIC OCEAN
OREGON
NOAA Chart: 18587 Latitude: 43° 20.5' N
USGS Quad: CAPE ARAGO Longitude: 124° 22.5' W
T I D A L D A T U M S
Tidal datums at CAPE ARAGO LIGHTHOUSE, PACIFIC OCEAN based on:
LENGTH OF SERIES: 1 MONTH
TIME PERIOD: DECEMBER 1976
TIDAL EPOCH: 1960-1978
CONTROL TIDE STATION: 9432780 CHARLESTON
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET:
HIGHEST OBSERVED WATER LEVEL (12/20/1976) = 9.74
MEAN HIGHER HIGH WATER MHHW = 7.55
MEAN HIGH WATER MHW = 6.87
MEAN TIDE LEVEL MTL = 3.99
MEAN LOW WATER MLW = 1.11
MEAN LOWER LOW WATER MLLW = 0.00
LOWEST OBSERVED WATER LEVEL (10/27/1976) = -1.06
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In FEET above:
Stamping or Designation MLLW MHW
TIDAL 1 1972 7.64 0.77
H 286 1939 54.2 58.44 51.57
TIDAL 2 1972 9.40 2.53
TIDAL 3 1972 10.59 3.72
TIDAL 4 1972 64.88 58.01
TIDAL ARAGO 4 1976 61.10 54.23
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
PUBLICATION DATE: 08/12/1986
Station ID: 9432771 SUPERCEDED DATE: 04/21/2003
Name: CAPE ARAGO LIGHTHOUSE, PACIFIC OCEAN
OREGON
NOAA Chart: 18587 Latitude: 43° 20.5' N
USGS Quad: CAPE ARAGO Longitude: 124° 22.5' W
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 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.