U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
PUBLICATION DATE: 09/19/1986
Station ID: 9441156 SUPERCEDED DATE: 04/21/2003
Name: POINT BROWN, GRAYS HARBOR
WASHINGTON
NOAA Chart: 18502 Latitude: 46° 56.9' N
USGS Quad: POINT BROWN Longitude: 124° 7.7' W
To reach the tidal bench marks from Hoquiam, proceed west on State Highway 109
for 16 miles (26 km) to State Highway 115, then SW on State Highway 115 for 2.3
miles (3.7 km) to Point Brown Avenue at the entrance to Ocean Shores
development, travel SE on Point Brown Avenue for 5.3 miles (8.5 km) to Discovery
Avenue (also known as Marine View Drive), then south on Discovery Avenue for 500
feet (152 m) to the entrance of the Ocean Shores Marina, then east for 740 feet
(226 m) past the grocery store, restaurant and fuel dock to the gravel road near
the boat launch, and then to a fish buyer pier just beyond the boat launch. The
bench marks are in the area around the marina. The tide gage and staff were
located on the north side of the pier.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 1156 A 1982
MONUMENTATION: Survey Disk VM#: 8982
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Wall
The bench mark is set flush in the eastern concrete wall to a boat launch ramp
between the fuel dock and fish buyer pier, 645 feet (197 m) NW of the rock
breakwater jetty marking the NW corner of the marina, 640 feet (195 m) east of
the entrance to Ocean Shores Marina, 19 feet (6 m) SE of the SE corner of a
small blue wooden building south of the fuel dock, and 4.8 feet (1.5 m) NE of
the SW corner of the eastern wall.
BENCH MARK STAMPING: 1156 B 1982
MONUMENTATION: Survey Disk VM#: 8983
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Pad
The bench mark is set flush in a 30 x 29-foot (9 x 9 m) concrete pad west of a
20-foot (6 m) square single-story building next to the marina fuel dock, 575
feet (175 m) east of the entrance to Ocean Shores Marina, 42.5 feet (13.0 m) WSW
of a lightpole with transformer located just to the east of the start of the
fuel dock pump, 5.5 feet (1.7 m) SE of the Chevron sign, and 1.4 feet (0.4 m) SE
of the NW corner of the concrete pad.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
PUBLICATION DATE: 09/19/1986
Station ID: 9441156 SUPERCEDED DATE: 04/21/2003
Name: POINT BROWN, GRAYS HARBOR
WASHINGTON
NOAA Chart: 18502 Latitude: 46° 56.9' N
USGS Quad: POINT BROWN Longitude: 124° 7.7' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1156 C 1982
MONUMENTATION: Survey Disk VM#: 8984
AGENCY: PID:
SETTING CLASSIFICATION: Aluminum Pipe Mark
The bench mark is a 4-foot (1 m) aluminum pipe buried in a concrete and earth
filled post hole and encased in a 4-inch PVC pipe in a planter centered in the
entrance of the Ocean Shores Marina, 463 feet (141 m) south of the intersection
of Marina View Drive and Point Brown Avenue, 37 feet (11 m) east of the
centerline of Marina View Drive, 24 feet (7 m) SE of a fire hydrant, and 0.1
foot (0.03 m) below ground level.
BENCH MARK STAMPING: 1156 D 1982
MONUMENTATION: Survey Disk VM#: 8985
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Tail Wall
The bench mark is set flush in the westernmost edge of the concrete tail wall
structure for the east-west underground drainage conducts on the east side of
Discovery Avenue, 517 feet (158 m) north of the intersection of Point Brown
Avenue and Discovery Avenue, 98 feet (30 m) east of the centerline of Discovery
Avenue, and 9.5 feet (2.9 m) south of the north end of the wall.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
PUBLICATION DATE: 09/19/1986
Station ID: 9441156 SUPERCEDED DATE: 04/21/2003
Name: POINT BROWN, GRAYS HARBOR
WASHINGTON
NOAA Chart: 18502 Latitude: 46° 56.9' N
USGS Quad: POINT BROWN Longitude: 124° 7.7' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO STAMPING 1
MONUMENTATION: Survey Disk VM#: 8986
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Foundation
The bench mark is set flush in the south end of a 2.3 x 22-foot (0.7 x 6.7 m)
concrete island near the registration driveway of Discovery Inn Condominium
-Motel, 758 feet (231 m) north along Discovery Avenue from the intersection of
Discovery Avenue and Point Brown Avenue, 98 feet (30 m) west of the centerline
of Discovery Avenue, and 0.3 foot (0.1 m) north of the south end of the concrete
island.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
PUBLICATION DATE: 09/19/1986
Station ID: 9441156 SUPERCEDED DATE: 04/21/2003
Name: POINT BROWN, GRAYS HARBOR
WASHINGTON
NOAA Chart: 18502 Latitude: 46° 56.9' N
USGS Quad: POINT BROWN Longitude: 124° 7.7' W
T I D A L D A T U M S
Tidal datums at POINT BROWN, GRAYS HARBOR based on:
LENGTH OF SERIES: 1 MONTH
TIME PERIOD: JUNE 1982
TIDAL EPOCH: 1960-1978
CONTROL TIDE STATION: 9439040 ASTORIA
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET:
HIGHEST OBSERVED WATER LEVEL (06/20/1982) = 11.35
MEAN HIGHER HIGH WATER MHHW = 9.38
MEAN HIGH WATER MHW = 8.65
MEAN TIDE LEVEL MTL = 5.04
MEAN LOW WATER MLW = 1.43
MEAN LOWER LOW WATER MLLW = 0.00
LOWEST OBSERVED WATER LEVEL (05/25/1982) = -2.46
Bench Mark Elevation Information In FEET above:
Stamping or Designation MLLW MHW
1156 A 1982 13.68 5.03
1156 B 1982 17.10 8.45
1156 C 1982 17.27 8.62
1156 D 1982 16.99 8.34
NO STAMPING 1 17.18 8.53
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
PUBLICATION DATE: 09/19/1986
Station ID: 9441156 SUPERCEDED DATE: 04/21/2003
Name: POINT BROWN, GRAYS HARBOR
WASHINGTON
NOAA Chart: 18502 Latitude: 46° 56.9' N
USGS Quad: POINT BROWN Longitude: 124° 7.7' 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.