U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 9446491 PUBLICATION DATE: 07/26/2004
Name: ARLETTA
WA
NOAA Chart: 18474 Latitude: 47° 16.8' N ( 47.28000)
USGS Quad: FOX ISLAND Longitude: 122° 39.1' W (-122.65200)
To reach the tidal bench marks from the north end of the bridge to Fox Island,
proceed west on Warren Road for 0.40 km (0.25 mi) to the abandoned Pierce County
Dock in Warren. The bench marks are in the vicinity of the dock and along the
shoreline west of the dock. The tide gage and staff were located on the south
end of the dock.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: NO 7 1952
DESIGNATION: 944 6491 TIDAL 7
MONUMENTATION: Tidal Station disk VM#: 9151
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Concrete sea wall OPUS PID:
LATITUDE: 47° 16.8' N ( 47.28000) LONGITUDE: 122° 39.1' W (-122.65200)
The primary bench mark is a disk set in the top of the east end of the first
concrete sea wall west of the abandoned Pierce County Dock at the junction of
the concrete sea wall with a sea wall constructed of concrete filled sacks, 300
m (984 ft) west of the dock, and 1 m (3 ft) west of the east end of the concrete
sea wall.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 9446491 PUBLICATION DATE: 07/26/2004
Name: ARLETTA
WA
NOAA Chart: 18474 Latitude: 47° 16.8' N ( 47.28000)
USGS Quad: FOX ISLAND Longitude: 122° 39.1' W (-122.65200)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: WARREN 1935
DESIGNATION: WARREN
MONUMENTATION: Triangulation Station disk VM#: 9149
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: SY2987
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 47° 17.0' N ( 47.28330) LONGITUDE: 122° 39.6' W (-122.66000)
The bench mark is a disk set in a concrete monument, 0.63 km (0.39 mi) west of
the abandoned Pierce County Dock, 9.30 m (30.5 ft) west of the western corner of
a concrete bulkhead, 7 m (23 ft) south of a 12 m (40 ft) cliff, and 3 cm (0.1
ft) above ground.
BENCH MARK STAMPING: NO 6 1952
DESIGNATION: 944 6491 TIDAL 6
MONUMENTATION: Tidal Station disk VM#: 9150
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Concrete staircase landing OPUS PID:
LATITUDE: 47° 16.8' N ( 47.28000) LONGITUDE: 122° 39.1' W (-122.65200)
The bench mark is a disk set in the SE corner of the landing at the top of a
concrete staircase leading to the beach at the west end of the first concrete
sea wall west of the abandoned Pierce County dock, 0.40 km (0.25 mi) west of the
dock, 100 m (328 ft) west of bench mark NO 7 1952, and 2 m (5 ft) above the
beach.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 9446491 PUBLICATION DATE: 07/26/2004
Name: ARLETTA
WA
NOAA Chart: 18474 Latitude: 47° 16.8' N ( 47.28000)
USGS Quad: FOX ISLAND Longitude: 122° 39.1' W (-122.65200)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 6491 H 1978
DESIGNATION: 944 6491 H TIDAL
MONUMENTATION: Tidal Station disk VM#: 9152
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Unspecified steel rod OPUS PID:
LATITUDE: 47° 16.8' N ( 47.28000) LONGITUDE: 122° 39.1' W (-122.65200)
The bench mark is a disk set 30.85 m (101.2 ft) west of the abandoned Pierce
County Dock, 15.03 m (49.3 ft) SW of a wooden flag pole with a concrete
foundation, 0.52 m (1.7 ft) south of a wooden bulkhead, and 0.43 m (1.4 ft) west
of the west end of a set of steps constructed from railroad ties. The bench
mark is set 9 cm (0.3 ft) above the gravel beach, crimped to the top of an
unspecified steel rod driven 6.1 m (20 ft) to refusal.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 9446491 PUBLICATION DATE: 07/26/2004
Name: ARLETTA
WA
NOAA Chart: 18474 Latitude: 47° 16.8' N ( 47.28000)
USGS Quad: FOX ISLAND Longitude: 122° 39.1' W (-122.65200)
T I D A L D A T U M S
Tidal datums at ARLETTA 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 = 4.055
MEAN HIGH WATER MHW = 3.780
MEAN TIDE LEVEL MTL = 2.339
MEAN SEA LEVEL MSL = 2.316
MEAN LOW WATER MLW = 0.898
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
NO 7 1952 5.038 1.258
WARREN 1935 3.502 -0.278
NO 6 1952 5.312 1.532
6491 H 1978 4.384 0.604
Foot Notes:
Bench marks NO 6 1952 and WARREN 1935 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: 9446491 PUBLICATION DATE: 07/26/2004
Name: ARLETTA
WA
NOAA Chart: 18474 Latitude: 47° 16.8' N ( 47.28000)
USGS Quad: FOX ISLAND Longitude: 122° 39.1' W (-122.65200)
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.