U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 4 Station ID: 9432771 PUBLICATION DATE: 08/09/2004 Name: CAPE ARAGO LIGHTHOUSE OR NOAA Chart: 18587 Latitude: 43° 20.5' N ( 43.34170) USGS Quad: CAPE ARAGO Longitude: 124° 22.0' W (-124.36700) To reach the tidal bench marks from Charleston, proceed west on Cape Arago Highway for 4.0 km (2.5 mi) 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 DESIGNATION: 943 2771 TIDAL 1 MONUMENTATION: Tidal Station disk VM#: 8782 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Bedrock OPUS PID: LATITUDE: 43° 20.5' N ( 43.34170) LONGITUDE: 124° 22.5' W (-124.37500) The primary bench mark is a disk set in bedrock, 119 m (390 ft) SW of Cape Arago Lighthouse, 5 m (17 ft) east of the centerline of the foot bridge leading to the lighthouse, 2 m (7 ft) south of the north end of a rocky outcrop at the south edge of the channel, and 2 m (6 ft) east of the third concrete footing from the south end of the bridge. BENCH MARK STAMPING: TIDAL 2 1972 DESIGNATION: 943 2771 TIDAL 2 MONUMENTATION: Tidal Station disk VM#: 8783 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Concrete bridge pier OPUS PID: LATITUDE: 43° 20.5' N ( 43.34170) LONGITUDE: 124° 22.5' W (-124.37500) The bench mark is a disk set flush in an old concrete bridge pier under the foot bridge, 1 m (3 ft) east of the centerline of the foot bridge, and 1 m (3 ft) south of the second bridge pier foundation from the south end of the bridge.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 4 Station ID: 9432771 PUBLICATION DATE: 08/09/2004 Name: CAPE ARAGO LIGHTHOUSE OR NOAA Chart: 18587 Latitude: 43° 20.5' N ( 43.34170) USGS Quad: CAPE ARAGO Longitude: 124° 22.0' W (-124.36700) T I D A L B E N C H M A R K S BENCH MARK STAMPING: TIDAL 3 1972 DESIGNATION: 943 2771 TIDAL 3 MONUMENTATION: Tidal Station disk VM#: 8784 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Concrete pier footing OPUS PID: LATITUDE: 43° 20.5' N ( 43.34170) LONGITUDE: 124° 22.5' W (-124.37500) The bench mark is a disk set flush in the NE corner of the most southeastern concrete pier footing of the foot bridge leading to the lighthouse, and 10 m (32 ft) below the deck of the bridge.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 4 Station ID: 9432771 PUBLICATION DATE: 08/09/2004 Name: CAPE ARAGO LIGHTHOUSE OR NOAA Chart: 18587 Latitude: 43° 20.5' N ( 43.34170) USGS Quad: CAPE ARAGO Longitude: 124° 22.0' W (-124.36700) T I D A L D A T U M S Tidal datums at CAPE ARAGO LIGHTHOUSE based on: LENGTH OF SERIES: 1 MONTH TIME PERIOD: December 1976 - December 1976 TIDAL EPOCH: 1983-2001 CONTROL TIDE STATION: 9432780 CHARLESTON, COOS BAY Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS: MEAN HIGHER HIGH WATER MHHW = 2.325 MEAN HIGH WATER MHW = 2.116 MEAN TIDE LEVEL MTL = 1.230 MEAN SEA LEVEL MSL = 1.184 MEAN LOW WATER MLW = 0.344 MEAN LOWER LOW WATER MLLW = 0.000 North American Vertical Datum (NAVD88) Bench Mark Elevation Information In METERS above: Stamping or Designation MLLW MHW TIDAL 1 1972 2.327 0.211 TIDAL 2 1972 2.862 0.746 TIDAL 3 1972 3.225 1.109
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 4 Station ID: 9432771 PUBLICATION DATE: 08/09/2004 Name: CAPE ARAGO LIGHTHOUSE OR NOAA Chart: 18587 Latitude: 43° 20.5' N ( 43.34170) USGS Quad: CAPE ARAGO Longitude: 124° 22.0' W (-124.36700) 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.