U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 4
PUBLICATION DATE: 07/31/1989
Station ID: 9446714 SUPERCEDED DATE: 04/21/2003
Name: STEILACOOM, NISQUALLY REACH, PUGET SOUND
WASHINGTON
NOAA Chart: 18448 Latitude: 47° 10.4' N
USGS Quad: STEILACOOM Longitude: 122° 36.2' W
To reach the tidal bench marks from the intersection of Commercial Street and
Union Avenue in Steilacoom, proceed 0.1 mile (0.2 km) NW on Union Avenue to the
foot of the McNeil Island Federal Penitentiary/Steilacoom Ferry pier. The tidal
bench marks are along the railroad tracks. The tide gage and staff were on the
pier, near the SW corner of the penitentiary check-in building.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 1917 NO 3
MONUMENTATION: Survey Disk VM#: 9178
AGENCY: PID#: SY0756
SETTING CLASSIFICATION: Concrete Monument
The bench mark is set in a concrete monument in an ivy covered area, 100 feet
(30 m) east of the centerline of Union Avenue, 47.3 feet (14.4 m) south of the
south corner of the residence at 105 Frederick Street, 44.2 feet (13.5 m) NE of
the SE pole supporting a WASHINGTON STATE HISTORICAL ROAD NO 1 sign, 35.2 feet
(10.7 m) NW of the centerline of Lafayette Street, 14.4 feet (4.4 m) NE of the
centerline of Frederick Street, 3.3 feet (1.0 m) NE of the NE edge of a sidewalk
along Frederick Street, and 2.5 feet (0.8 m) south of a witness post.
BENCH MARK STAMPING: 1917 NO 1
MONUMENTATION: Survey Disk VM#: 9176
AGENCY: PID#: SY0754
SETTING CLASSIFICATION: Concrete Pad
The bench mark is set in the west corner of the concrete pad for a carport
attached to the SW end of the Burlington-Northern Railroad Station building,
31.8 feet (9.7 m) SSW of the west corner of the station, 28.1 feet (8.6 m) SE of
the SE rail of the SE main track, 0.9 foot (0.3 m) SE of the SE face of the west
brick and concrete carport pier, and 0.7 foot (0.2 m) NE of the SW edge of the
pad.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 4
PUBLICATION DATE: 07/31/1989
Station ID: 9446714 SUPERCEDED DATE: 04/21/2003
Name: STEILACOOM, NISQUALLY REACH, PUGET SOUND
WASHINGTON
NOAA Chart: 18448 Latitude: 47° 10.4' N
USGS Quad: STEILACOOM Longitude: 122° 36.2' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1917 NO 2
MONUMENTATION: Survey Disk VM#: 9177
AGENCY: PID#: SY0755
SETTING CLASSIFICATION: Rock Outcrop
The bench mark is set in a rock outcrop in a grassy park overlook area, 75.8
feet (23.1 m) NW of a fire hydrant, 57 feet (17 m) SW of the extended centerline
of Wilkes Street, 50 feet (15 m) NW of the centerline of Commercial Street, 34.2
feet (10.4 m) west of a power pole with two guy wires, 4.0 feet (1.2 m) south of
a witness post, 1.0 foot (0.3 m) lower than street level, and 0.5 foot (0.2 m)
above ground level.
BENCH MARK STAMPING: TIDAL 8 1971
MONUMENTATION: Survey Disk VM#: 9179
AGENCY: PID#: SY0757
SETTING CLASSIFICATION: Concrete Wingwall
The bench mark is set in the center of the east concrete wingwall of the SW
abutment of the ferry pier, 18.8 feet (5.7 m) NW of the NW rail of the NW main
railroad track, 11 feet (3 m) NE of the centerline of the pier, 2.5 feet (0.8
m) lower than the railroad tracks and pier deck, and 1.8 feet (0.5 m) east of
the NE end of the abutment.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 4
PUBLICATION DATE: 07/31/1989
Station ID: 9446714 SUPERCEDED DATE: 04/21/2003
Name: STEILACOOM, NISQUALLY REACH, PUGET SOUND
WASHINGTON
NOAA Chart: 18448 Latitude: 47° 10.4' N
USGS Quad: STEILACOOM Longitude: 122° 36.2' W
T I D A L D A T U M S
Tidal datums at STEILACOOM, NISQUALLY REACH, PUGET SOUND based on:
LENGTH OF SERIES: 33 HW & 32 LW
TIME PERIOD: MARCH 9-25, 1978
TIDAL EPOCH: 1960-1978
CONTROL TIDE STATION: 9447130 SEATTLE
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET:
HIGHEST OBSERVED WATER LEVEL (03/09/1978) = 14.71
MEAN HIGHER HIGH WATER MHHW = 13.48
MEAN HIGH WATER MHW = 12.57
MEAN TIDE LEVEL MTL = 7.77
* NATIONAL GEODETIC VERTICAL DATUM NGVD29 = 7.11
MEAN LOW WATER MLW = 2.98
MEAN LOWER LOW WATER MLLW = 0.00
* NGVD reference based on elevations published in Quad N471223, 1985, and NOS
leveling of 1978.
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In FEET above:
Stamping or Designation MLLW MHW
1917 NO 3 58.05 45.48
1917 NO 1 22.08 9.51
1917 NO 2 72.21 59.64
TIDAL 8 1971 19.14 6.57
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 4
PUBLICATION DATE: 07/31/1989
Station ID: 9446714 SUPERCEDED DATE: 04/21/2003
Name: STEILACOOM, NISQUALLY REACH, PUGET SOUND
WASHINGTON
NOAA Chart: 18448 Latitude: 47° 10.4' N
USGS Quad: STEILACOOM Longitude: 122° 36.2' 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.