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National Ocean Service
Datums Page Page 1 of 5
Station ID: 9446742 PUBLICATION DATE: 05/01/2003
Name: BARRON POINT, LITTLE SKOOKUM INLET ENT
WA
NOAA Chart: 18448 Latitude: 47° 9.4' N ( 47.15670)
USGS Quad: SHELTON Longitude: 123° 0.5' W (-123.00800)
To reach the tidal bench marks from Olympia, proceed 1.6 km (1.0 mi) north on
U.S. Highway 101 toward Shelton beyond the intersection with Highway 108 to
Lynch Road, then east on Lynch Road for 7.2 km (4.5 mi) to the Bay East
community marked by a sign, then turn east into the community and follow the
main road straight to the boat ramp. The bench marks are near the boat ramp and
SW along the shoreline. The tide gauge and staff were on the Bay East pier.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 6742 C 1988
DESIGNATION: 944 6742 C
MONUMENTATION: Tidal Station disk VM#: 12033
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Bedrock outcrop OPUS PID:
LATITUDE: 47° 9.4' N ( 47.15670) LONGITUDE: 123° 0.3' W (-123.00500)
The primary bench mark is a disk set in a small bedrock outcrop, 165 m (540 ft)
SW of the Bay East pier, 62 m (204 ft) NE of a wooden pier (in poor condition),
9 m (28 ft) SE of a 0.30 m x 0.76 m ((1.0 ft x 2.5 ft) concrete landing
supporting wooden stairs leading down from the bluff, and 0.30 m (1.0 ft) above
the beach.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 9446742 PUBLICATION DATE: 05/01/2003
Name: BARRON POINT, LITTLE SKOOKUM INLET ENT
WA
NOAA Chart: 18448 Latitude: 47° 9.4' N ( 47.15670)
USGS Quad: SHELTON Longitude: 123° 0.5' W (-123.00800)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 6742 A 1988
DESIGNATION: 944 6742 A
MONUMENTATION: Tidal Station disk VM#: 12031
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete boat ramp OPUS PID:
LATITUDE: 47° 9.4' N ( 47.15670) LONGITUDE: 123° 0.3' W (-123.00500)
The bench mark is a disk set in a concrete boat ramp at Barron Point, 39 m (128
ft) NW of the inshore end of the Bay East pier, 7 m (24 ft) NW of the north end
of a wooden log embankment wall, and 0.46 m (1.5 ft) NW of the SE edge of the
ramp.
BENCH MARK STAMPING: 6742 B 1988
DESIGNATION: 944 6742 B
MONUMENTATION: Tidal Station disk VM#: 12032
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete foundation OPUS PID:
LATITUDE: 47° 9.4' N ( 47.15670) LONGITUDE: 123° 0.3' W (-123.00500)
The bench mark is a disk set in a 6 m x 6 m (20 ft x 20 ft) concrete foundation
for a small building immediately shoreward of the inshore end of the Bay East
pier, 40.45 m (132.7 ft) SW of bench mark 6742 A 1988, 1.01 m (3.3 ft) NE of the
north corner of the building, and 0.21 m (0.7 ft) SW of the NE edge of the
foundation.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 9446742 PUBLICATION DATE: 05/01/2003
Name: BARRON POINT, LITTLE SKOOKUM INLET ENT
WA
NOAA Chart: 18448 Latitude: 47° 9.4' N ( 47.15670)
USGS Quad: SHELTON Longitude: 123° 0.5' W (-123.00800)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 6742 D 1988
DESIGNATION: 944 6742 D
MONUMENTATION: Tidal Station disk VM#: 12034
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Granite bedrock outcrop OPUS PID:
LATITUDE: 47° 9.4' N ( 47.15670) LONGITUDE: 123° 0.3' W (-123.00500)
The bench mark is a disk set in a 1 m x 2 m (3 ft x 6 ft) granite bedrock
outcrop, 59 m (195 ft) SW of a wooden dock, 50 m (165 ft) NE of a large 4 m (12
ft) high rock, and 7 m (24 ft) SE of the foot of a bluff.
BENCH MARK STAMPING: 6742 E 1988
DESIGNATION: 944 6742 E
MONUMENTATION: Tidal Station disk VM#: 12035
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: High rock OPUS PID:
LATITUDE: 47° 9.4' N ( 47.15670) LONGITUDE: 123° 0.3' W (-123.00500)
The bench mark is a disk set vertically in the north face of a 4 m (12 ft) high
rock, 50 m (165 ft) SW of bench mark 6742 D 1988, and 1 m (4 ft) above the
beach.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 9446742 PUBLICATION DATE: 05/01/2003
Name: BARRON POINT, LITTLE SKOOKUM INLET ENT
WA
NOAA Chart: 18448 Latitude: 47° 9.4' N ( 47.15670)
USGS Quad: SHELTON Longitude: 123° 0.5' W (-123.00800)
T I D A L D A T U M S
Tidal datums at BARRON POINT, LITTLE SKOOKUM INLET ENT based on:
LENGTH OF SERIES: 1 MONTH
TIME PERIOD: October 1988 - October 1988
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 = 4.426
MEAN HIGH WATER MHW = 4.130
MEAN SEA LEVEL MSL = 2.527
MEAN TIDE LEVEL MTL = 2.525
MEAN LOW WATER MLW = 0.920
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
6742 C 1988 3.861 -0.269
6742 A 1988 4.938 0.808
6742 B 1988 5.473 1.343
6742 D 1988 4.225 0.095
6742 E 1988 5.047 0.917
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 9446742 PUBLICATION DATE: 05/01/2003
Name: BARRON POINT, LITTLE SKOOKUM INLET ENT
WA
NOAA Chart: 18448 Latitude: 47° 9.4' N ( 47.15670)
USGS Quad: SHELTON Longitude: 123° 0.5' W (-123.00800)
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.