U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
PUBLICATION DATE: 01/29/1988
Station ID: 9446545 SUPERCEDED DATE: 04/21/2003
Name: TACOMA, COMMENCEMENT BAY
WASHINGTON
NOAA Chart: 18453 Latitude: 47° 15.3' N
USGS Quad: TACOMA NORTH Longitude: 122° 25.9' W
To reach the tidal bench marks from the intersection of Pacific Avenue and East
11st Street in Tacoma, Washington proceed east along 11th Street for 0.5 miles
(0.8 km), cross over the 11th Street Bridge and city waterway to east E Street,
turn left (north), then another left (west) immediately onto 11th Street lower
level and travel 0.2 miles (0.3 km) to the Tacoma City Fire boat station and
slip adjacent to the north side of the 11th Street bridge. The bench marks are
located along the Railroad tracks around the station, and the tide gage and
staff were located on a piling clump 72 feet (22 m) west of the onshore fire
boat station.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: E 406 1965
MONUMENTATION: Survey Disk VM#: 9161
AGENCY: PID#: SY0534
SETTING CLASSIFICATION: Concrete Curb
The bench mark is set in the top of the east end of the south concrete curb of
the East 11th Street bridge over the city waterway, 6.0 feet (1.8 m) south of
the south curb of East 11th Street, 0.5 foot (0.2 m) north of the east end of a
guard rail, 0.5 foot (0.2 m) north of the NW corner of the top of five concrete
steps, and about the level with the street.
BENCH MARK STAMPING: F 11 1920 ELEV. 26.227 FT.
MONUMENTATION: Survey Disk VM#: 9158
AGENCY: PID#: SY0541
SETTING CLASSIFICATION: Wall
The bench mark is set in the east wall of a heating plant building, at the SE
corner of the main building of the Union Station, 4.0 feet (1.2 m) south of the
south stairway leading from the station platform to Pacific Avenue, 1.5 feet
(0.5 m) from the north wall of the building, and 3.5 feet (1.1 m) above the
platform.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
PUBLICATION DATE: 01/29/1988
Station ID: 9446545 SUPERCEDED DATE: 04/21/2003
Name: TACOMA, COMMENCEMENT BAY
WASHINGTON
NOAA Chart: 18453 Latitude: 47° 15.3' N
USGS Quad: TACOMA NORTH Longitude: 122° 25.9' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: G 11 1920 ELEV. 17.487 FT.
MONUMENTATION: Survey Disk VM#: 9159
AGENCY: PID#: SY0533
SETTING CLASSIFICATION: Concrete Abutment
The bench mark is set vertically in the east face of the west concrete abutment
of the South 15th Street bridge over the railroad yard, 22.5 feet (6.9 m) west
of the west rail of the west track, 1.5 feet (0.5 m) south of the north end of
the abutment 2 feet (0.6 m) higher than the track, and 1 foot (0.3 m) above the
ground.
BENCH MARK STAMPING: NO 23 1952
MONUMENTATION: Survey Disk VM#: 9160
AGENCY: PID#: SY0532
SETTING CLASSIFICATION: Concrete Foundation
The bench mark is set in the top of a 2 x 2 foot (1x1 m) concrete piling, a
former foundation for the dock, 100 feet (30 m) east of the centerline of Dock
Street, and 38 feet (12 m) north of the north end of the Municipal Dock
Building.
BENCH MARK STAMPING: F 406 1965
MONUMENTATION: Survey Disk VM#: 9162
AGENCY: PID#: SY0535
SETTING CLASSIFICATION: Concrete Retaining Wall
The bench mark is set in the top of the SW end of the SE concrete retaining wall
for the 11th Street bridge over the Puyallup River, 4.5 feet (1.4 m) SW of the
SE curb of East 11th Street, 4.5 feet (1.4 m) NE of the SW end of a guardrail,
0.5 foot (0.2 m) higher than the street, and level with the sidewalk.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
PUBLICATION DATE: 01/29/1988
Station ID: 9446545 SUPERCEDED DATE: 04/21/2003
Name: TACOMA, COMMENCEMENT BAY
WASHINGTON
NOAA Chart: 18453 Latitude: 47° 15.3' N
USGS Quad: TACOMA NORTH Longitude: 122° 25.9' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: TIDAL BM 24 1974
MONUMENTATION: Survey Disk VM#: 9163
AGENCY: PID:
SETTING CLASSIFICATION: Wall
The bench mark is located on the parking lot wall of the Pacific National Bank
of Washington, 135 feet (41 m) north of the corner of South 13th Street, 51.7
feet (15.8 m) east of the centerline of Pacific Avenue, and 3.5 feet (1.1 m)
above the sidewalk.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
PUBLICATION DATE: 01/29/1988
Station ID: 9446545 SUPERCEDED DATE: 04/21/2003
Name: TACOMA, COMMENCEMENT BAY
WASHINGTON
NOAA Chart: 18453 Latitude: 47° 15.3' N
USGS Quad: TACOMA NORTH Longitude: 122° 25.9' W
T I D A L D A T U M S
Tidal datums at TACOMA, COMMENCEMENT BAY based on:
LENGTH OF SERIES: 9 MONTHS
TIME PERIOD: APRIL 1977-FEBRUARY 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 (12/15/1977) = 14.98
MEAN HIGHER HIGH WATER MHHW = 11.84
MEAN HIGH WATER MHW = 10.96
MEAN TIDE LEVEL MTL = 6.91
* NATIONAL GEODETIC VERTICAL DATUM NGVD29 = 6.32
MEAN LOW WATER MLW = 2.86
MEAN LOWER LOW WATER MLLW = 0.00
LOWEST OBSERVED WATER LEVEL (06/02/1977) = -3.84
* NGVD reference based on adjustment of 1966 and NOS levels of 1977-78.
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In FEET above:
Stamping or Designation MLLW MHW
E 406 1965 23.63 12.67
F 11 1920 ELEV. 26.227 FT. 32.54 21.58
G 11 1920 ELEV. 17.487 FT. 23.78 12.82
NO 23 1952 21.52 10.56
F 406 1965 26.47 15.51
TIDAL BM 24 1974 85.28 74.32
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
PUBLICATION DATE: 01/29/1988
Station ID: 9446545 SUPERCEDED DATE: 04/21/2003
Name: TACOMA, COMMENCEMENT BAY
WASHINGTON
NOAA Chart: 18453 Latitude: 47° 15.3' N
USGS Quad: TACOMA NORTH Longitude: 122° 25.9' 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.