U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 5 Station ID: 9446451 PUBLICATION DATE: 06/16/2004 Name: GREEN POINT WA NOAA Chart: 18448 Latitude: 47° 18.1' N ( 47.30170) USGS Quad: FOX ISLAND Longitude: 122° 40.9' W (-122.68200) To reach the tidal bench marks from Arletta, proceed 1.9 km (1.2 mi) north to the NE end of Horsehead Bay. The bench marks are located in the sea wall around the residence of Mr. William Busch. The tide gage and staff were located on the wooden pier on the property. NOTE: The owner is very privacy conscious, contact before occupying. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: 6451 B 1978 DESIGNATION: 944 6451 B TIDAL MONUMENTATION: Tidal Station disk VM#: 9138 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Concrete sea wall OPUS PID: LATITUDE: 47° 18.1' N ( 47.30170) LONGITUDE: 122° 40.9' W (-122.68200) The primary bench mark is a disk set in the top of a concrete sea wall west of a private home at the NE end of Horsehead Bay, 21 m (68 ft) north of the NE end of the pier at a junction with a sidewalk leading to the residence, 4 m (13 ft) south of a brick firepit, 1 m (4 ft) NW of a large fir tree, and 0.5 m (1.5 ft) above the beach.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 5 Station ID: 9446451 PUBLICATION DATE: 06/16/2004 Name: GREEN POINT WA NOAA Chart: 18448 Latitude: 47° 18.1' N ( 47.30170) USGS Quad: FOX ISLAND Longitude: 122° 40.9' W (-122.68200) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 6451 A 1978 DESIGNATION: 944 6451 A TIDAL MONUMENTATION: Tidal Station disk VM#: 9137 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Concrete sea wall OPUS PID: LATITUDE: 47° 18.1' N ( 47.30170) LONGITUDE: 122° 40.9' W (-122.68200) The bench mark is a disk set in the top of the north end of the concrete sea wall winding north-southeasterly, west of the private home at the NE end of Horsehead Bay, 50 m (164 ft) north of bench mark 6451 B 1978, 9 m (28 ft) NW of a 6 m (20 ft) tree stump, and 1 m (3 ft) above the base of the sea wall. BENCH MARK STAMPING: 6451 C 1978 DESIGNATION: 944 6451 C TIDAL MONUMENTATION: Tidal Station disk VM#: 9139 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Concrete sea wall OPUS PID: LATITUDE: 47° 18.1' N ( 47.30170) LONGITUDE: 122° 40.9' W (-122.68200) The bench mark is a disk set in the top of a concrete sea wall west of a private home at the NE end of Horsehead Bay, 50 m (164 ft) SE of bench mark 6451 B 1978, and 2 m (6 ft) west of the SE end of the sea wall.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 5 Station ID: 9446451 PUBLICATION DATE: 06/16/2004 Name: GREEN POINT WA NOAA Chart: 18448 Latitude: 47° 18.1' N ( 47.30170) USGS Quad: FOX ISLAND Longitude: 122° 40.9' W (-122.68200) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 6451 D 1978 DESIGNATION: 944 6451 D TIDAL MONUMENTATION: Tidal Station disk VM#: 9140 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Concrete sea wall OPUS PID: LATITUDE: 47° 18.1' N ( 47.30170) LONGITUDE: 122° 40.9' W (-122.68200) The bench mark is a disk set in the top of a concrete sea wall, near the corner of the junction of a sidewalk cutting through the wall to the beach, 121 m (400 ft) south of the prominent pier leading seaward from the private residence at the NE end of Horsehead Bay, 70 m (230 ft) south of bench mark 6451 C 1978, and 6 m (20 ft) SSW of a large fir tree. BENCH MARK STAMPING: 6451 E 1978 DESIGNATION: 944 6451 E TIDAL MONUMENTATION: Tidal Station disk VM#: 9141 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Concrete sea wall OPUS PID: LATITUDE: 47° 18.1' N ( 47.30170) LONGITUDE: 122° 40.9' W (-122.68200) The bench mark is a disk set in top of a concrete sea wall, 198 m (650 ft) south of the prominent pier leading seaward from the private residence at the NE end of Horsehead Bay, 70 m (230 ft) south of bench mark 6451 D 1978, and 20 m (65 ft) south of a sidewalk cut in the sea wall. The bench mark is 2 m (7 ft) above beach level at the sea wall.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 5 Station ID: 9446451 PUBLICATION DATE: 06/16/2004 Name: GREEN POINT WA NOAA Chart: 18448 Latitude: 47° 18.1' N ( 47.30170) USGS Quad: FOX ISLAND Longitude: 122° 40.9' W (-122.68200) T I D A L D A T U M S Tidal datums at GREEN POINT based on: LENGTH OF SERIES: 1 MONTH TIME PERIOD: March 1978 - March 1978 TIDAL EPOCH: 1983-2001 CONTROL TIDE STATION: 9447130 SEATTLE, PUGET SOUND Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS: MEAN HIGHER HIGH WATER MHHW = 4.105 MEAN HIGH WATER MHW = 3.825 MEAN TIDE LEVEL MTL = 2.365 MEAN SEA LEVEL MSL = 2.354 MEAN LOW WATER MLW = 0.905 MEAN LOWER LOW WATER MLLW = 0.000 North American Vertical Datum (NAVD88) Bench Mark Elevation Information In METERS above: Stamping or Designation MLLW MHW 6451 B 1978 5.296 1.471 6451 A 1978 5.378 1.553 6451 C 1978 5.336 1.511 6451 D 1978 5.344 1.519 6451 E 1978 5.363 1.538 Foot Notes: Bench marks 6451 A 1978, 6451 C 1978, 6451 D 1978,and 6451 E 1978 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: 9446451 PUBLICATION DATE: 06/16/2004 Name: GREEN POINT WA NOAA Chart: 18448 Latitude: 47° 18.1' N ( 47.30170) USGS Quad: FOX ISLAND Longitude: 122° 40.9' W (-122.68200) 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.