U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 6
Station ID: 9441156 PUBLICATION DATE: 07/12/2004
Name: POINT BROWN
WA
NOAA Chart: 18502 Latitude: 46° 57.0' N ( 46.95000)
USGS Quad: POINT BROWN Longitude: 124° 7.7' W (-124.12800)
To reach the tidal bench marks from Hoquiam, proceed west on State Highway 109
for 26 km (16 mi) to State Highway 115, then turn left and proceed south on
State Highway 115 for 3.7 km (2.3 mi) to Point Brown Avenue at the entrance to
the Ocean Shores development, then turn left and proceed SE on Point Brown
Avenue for 8.5 km (5.3 mi) to Discovery Avenue (also known as Marine View
Drive), then turn right and proceed south on Discovery Avenue for 152 m (500 ft)
to the entrance of the Ocean Shores Marina, then turn left and proceed east for
226 m (740 ft) past the grocery store, restaurant and fuel dock to the gravel
road near the boat launch, and proceed 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
DESIGNATION: 944 1156 A TIDAL
MONUMENTATION: Tidal Station disk VM#: 8982
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete wall OPUS PID:
LATITUDE: 46° 56.9' N ( 46.94830) LONGITUDE: 124° 7.7' W (-124.12800)
The primary bench mark is a disk set in the eastern concrete wall to a boat
launch ramp between the fuel dock and fish buyer pier, 197 m (645 ft) NW of the
rock breakwater jetty marking the NW corner of the marina, 195 m (640 ft) east
of the entrance to Ocean Shores Marina, 6 m (19 ft) SE of the SE corner of a
small blue wooden building south of the fuel dock, and 1.46 m (4.8 ft) NE of the
SW corner of the eastern wall.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 6
Station ID: 9441156 PUBLICATION DATE: 07/12/2004
Name: POINT BROWN
WA
NOAA Chart: 18502 Latitude: 46° 57.0' N ( 46.95000)
USGS Quad: POINT BROWN Longitude: 124° 7.7' W (-124.12800)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1156 B 1982
DESIGNATION: 944 1156 B TIDAL
MONUMENTATION: Tidal Station disk VM#: 8983
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete pad OPUS PID:
LATITUDE: 46° 56.9' N ( 46.94830) LONGITUDE: 124° 7.7' W (-124.12800)
The bench mark is a disk set in a 9 m x 9 m (30 ft x 29 ft) concrete pad west of
a 6 m (20 ft) square single-story building next to the marina fuel dock, 175 m
(575 ft) east of the entrance to Ocean Shores Marina, 12.95 m (42.5 ft) WSW of a
lightpole with transformer located just to the east of the start of the fuel
dock pump, 1.68 m (5.5 ft) SE of the Chevron sign, and 0.43 m (1.4 ft) SE of the
NW corner of the concrete pad.
BENCH MARK STAMPING: 1156 C 1982
DESIGNATION: 944 1156 C TIDAL
MONUMENTATION: Aluminum marker VM#: 8984
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Aluminum pipe surrounded by concrete OPUS PID:
LATITUDE: 46° 56.9' N ( 46.94830) LONGITUDE: 124° 7.7' W (-124.12800)
The bench mark is a 1 m (4 ft) 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, 141 m (463 ft) south of the intersection of
Marina View Drive and Point Brown Avenue, 11 m (37 ft) east of the centerline of
Marina View Drive, 7 m (24 ft) SE of a fire hydrant, and 3 cm (0.1 ft) below
ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 6
Station ID: 9441156 PUBLICATION DATE: 07/12/2004
Name: POINT BROWN
WA
NOAA Chart: 18502 Latitude: 46° 57.0' N ( 46.95000)
USGS Quad: POINT BROWN Longitude: 124° 7.7' W (-124.12800)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1156 D 1982
DESIGNATION: 944 1156 D TIDAL
MONUMENTATION: Tidal Station disk VM#: 8985
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete tail wall OPUS PID:
LATITUDE: 46° 56.9' N ( 46.94830) LONGITUDE: 124° 7.7' W (-124.12800)
The bench mark is a disk set flush in the westernmost edge of the concrete tail
wall structure for the east-west underground drainage conducts located on the
east side of Discovery Avenue, 158 m (517 ft) north of the intersection of Point
Brown Avenue and Discovery Avenue, 30 m (98 ft) east of the centerline of
Discovery Avenue, and 2.90 m (9.5 ft) south of the north end of the wall.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 6
Station ID: 9441156 PUBLICATION DATE: 07/12/2004
Name: POINT BROWN
WA
NOAA Chart: 18502 Latitude: 46° 57.0' N ( 46.95000)
USGS Quad: POINT BROWN Longitude: 124° 7.7' W (-124.12800)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING:
DESIGNATION: 944 1156 E
ALIAS: NO STAMPING 1, E 1982
MONUMENTATION: Tidal Station disk VM#: 8986
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete island OPUS PID:
LATITUDE: 46° 56.9' N ( 46.94830) LONGITUDE: 124° 7.7' W (-124.12800)
The bench mark is a disk set flush in the south end of a 0.7 m x 6.7 m (2.3 ft x
22 ft) concrete island near the registration driveway of Discovery Inn
Condominium - Motel, 231 m (758 ft) north along Discovery Avenue from the
intersection of Discovery Avenue and Point Brown Avenue, 30 m (98 ft) west of
the centerline of Discovery Avenue, and 0.06 m (0.2 ft) north of the south end
of the concrete island.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 6
Station ID: 9441156 PUBLICATION DATE: 07/12/2004
Name: POINT BROWN
WA
NOAA Chart: 18502 Latitude: 46° 57.0' N ( 46.95000)
USGS Quad: POINT BROWN Longitude: 124° 7.7' W (-124.12800)
T I D A L D A T U M S
Tidal datums at POINT BROWN based on:
LENGTH OF SERIES: 1 MONTH
TIME PERIOD: June 1982 - June 1982
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 = 2.925
MEAN HIGH WATER MHW = 2.700
MEAN SEA LEVEL MSL = 1.595
MEAN TIDE LEVEL MTL = 1.576
MEAN LOW WATER MLW = 0.452
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
1156 A 1982 4.208 1.508
1156 B 1982 5.251 2.551
1156 C 1982 5.301 2.601
1156 D 1982 5.217 2.517
944 1156 E 5.276 2.576
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 6
Station ID: 9441156 PUBLICATION DATE: 07/12/2004
Name: POINT BROWN
WA
NOAA Chart: 18502 Latitude: 46° 57.0' N ( 46.95000)
USGS Quad: POINT BROWN Longitude: 124° 7.7' W (-124.12800)
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.