U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 6
PUBLICATION DATE: 09/11/2000
Station ID: 9446484 SUPERCEDED DATE: 04/21/2003
Name: TACOMA, COMMENCEMENT BAY
WASHINGTON
NOAA Chart: 18453 Latitude: 47° 16.0' N
USGS Quad: Tacoma North Longitude: 122° 24.8' W
To reach the tidal bench marks proceed west about 5 km (3 mi) from the
intersection of exit 136 of Interstate I-5 and Port of Tacoma Road, turn left
onto 11th Street and proceed 0.5 km (0.3 mi), turn right, just before the
bridge, into the Port of Tacoma Administration Building. The bench marks are in
the vicinity of the Port of Tacoma Administration Building. The tide station is
located on the north side of the building at the eastern end of Pier 7.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 6484 A 1996
DESIGNATION: 944 6484 A
MONUMENTATION: Bench Mark disk VM#: 13310
AGENCY: National Ocean Service PID:
SETTING CLASSIFICATION: Stainless steel rod
The primary bench mark is a disk located in a dirt area between the east end of
the Port of Tacoma observation tower and the parking lot, 2.41 m (7.9 ft) east
of stairway leading to the top of the tower, 1.25 m (4.1 ft) south of the
southernmost of 2 lights, and 0.49 m (1.6 ft) north of a concrete wall
surrounding the tower. The bench mark is set 15 cm (0.5 ft) below grade, crimped
to a stainless steel rod driven 30.5 m (100 ft) to refusal, and is encased in a
PVC pipe with concrete kickblock.
BENCH MARK STAMPING: 6484 B 1996
DESIGNATION: 944 6484 B
MONUMENTATION: Bench Mark disk VM#: 13311
AGENCY: National Ocean Service PID:
SETTING CLASSIFICATION: Concrete Wall
The bench mark is a disk set in a concrete wall on the western edge of the
parking lot on the north side of the Port of Tacoma Administration Building,
28.90 m (94.8 ft) NW of the corner of the Port of Tacoma Administration
Building, 18 m (59 ft) SW of a lightpole, 5.49 m (18.0 ft) SE of a telephone
utility box on the eastern edge of Pier 7, 0.15 m (0.5 ft) north of a retaining
wall, and 0.09 m (0.3 ft) above the parking lot level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 6
PUBLICATION DATE: 09/11/2000
Station ID: 9446484 SUPERCEDED DATE: 04/21/2003
Name: TACOMA, COMMENCEMENT BAY
WASHINGTON
NOAA Chart: 18453 Latitude: 47° 16.0' N
USGS Quad: Tacoma North Longitude: 122° 24.8' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 6484 C 1996
DESIGNATION: 944 6484 C
MONUMENTATION: Bench Mark disk VM#: 13312
AGENCY: National Ocean Service PID:
SETTING CLASSIFICATION: Concrete Slab
The bench mark is a disk set in the concrete loading dock at the west end of
Pier 7 at 2205 Sitcom way, 6.25 m (20.5 ft) west of the east end of the dock,
6.25 m (20.5 ft) south of a large sliding door, 0.30 m (1.0 ft) north of south
end of loading dock, and 1 m (3 ft) above ground.
BENCH MARK STAMPING: E 406 1965
DESIGNATION: E 406
MONUMENTATION: Bench Mark disk VM#: 13313
AGENCY: USC&GS PID#: SY0534
SETTING CLASSIFICATION: Pavement
The bench mark is a disk set in the top at the east end of the south concrete
curb of the 11th street bridge over the city waterway, 1.80 m (5.9 ft) south of
the south curb of east 11th street, 0.18 m (0.6 ft) north of the east end of a
guard rail, 0.18 m (0.6 ft) north of the NW corner of the top of five concrete
steps, and level with the street.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 6
PUBLICATION DATE: 09/11/2000
Station ID: 9446484 SUPERCEDED DATE: 04/21/2003
Name: TACOMA, COMMENCEMENT BAY
WASHINGTON
NOAA Chart: 18453 Latitude: 47° 16.0' N
USGS Quad: Tacoma North Longitude: 122° 24.8' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: F 406 1965
DESIGNATION: F 406
MONUMENTATION: Bench Mark disk VM#: 13314
AGENCY: USC&GS PID#: SY0535
SETTING CLASSIFICATION: Concrete Retaining Wall
The bench mark is a disk set in the top at the SW end of the SE concrete
retaining wall for the 11th street bridge over the Puyallup River, 1.40 m (4.6
ft) SW of the SE curb of East 11th Street, 1.40 m (4.6 ft) NE of the SW end of a
guardrail, 0.18 m (0.6 ft) higher than the street, and level with the sidewalk.
BENCH MARK STAMPING: TIDE 22 1933
DESIGNATION: TIDAL 22
MONUMENTATION: Tidal Station disk VM#: 13315
AGENCY: USC&GS PID#: SY0536
SETTING CLASSIFICATION: Pavement
The bench mark is a disk set in a 1 x 1 m (3 x 3 ft) concrete slab of the NW
sidewalk at the NE end of East 11 Street bridge over Puyallup River, 2.80 m (9.2
ft) NW of the curb of the Street, 1.10 m (3.6 ft) NW of a lamp post, 0.61 m (2.0
ft) NE of the SW edge of the concrete slab, and 0.30 m (1.0 ft) above the street
level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 6
PUBLICATION DATE: 09/11/2000
Station ID: 9446484 SUPERCEDED DATE: 04/21/2003
Name: TACOMA, COMMENCEMENT BAY
WASHINGTON
NOAA Chart: 18453 Latitude: 47° 16.0' N
USGS Quad: Tacoma North Longitude: 122° 24.8' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING:
DESIGNATION: 944 6484 POT 101
ALIAS: POT 101
MONUMENTATION: Bench Mark disk VM#: 13316
AGENCY: WSDOT PID:
SETTING CLASSIFICATION: Pavement
The bench mark is a Washington State Department of Transportation disk set in
the pavement at the intersection of 11th Street and Port of Tacoma Road, 19.29 m
(63.3 ft) SE of the base of a large street light, 7.59 m (24.9 ft) east of the
railroad tracks going into the Port of Tacoma, and 0.18 m (0.6 ft) below the
street level under a manhole cover with WSDOT marking.
BENCH MARK STAMPING:
DESIGNATION: 944 6484 POT 925
ALIAS: POT 925
MONUMENTATION: Bench Mark disk VM#: 13317
AGENCY: WSDOT PID:
SETTING CLASSIFICATION: Pavement
The bench mark is a Washington State Department of Transportation disk set in
pavement at the intersection of 11th Street and Thorne Road, 11.22 m (36.8 ft)
NE of a railroad crossing light and signal, 7 m (23 ft) east of the western side
of the 11th Street, and 0.21 m (0.7 ft) below the street level under a manhole
cover with WSDOT marking.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 6
PUBLICATION DATE: 09/11/2000
Station ID: 9446484 SUPERCEDED DATE: 04/21/2003
Name: TACOMA, COMMENCEMENT BAY
WASHINGTON
NOAA Chart: 18453 Latitude: 47° 16.0' N
USGS Quad: Tacoma North Longitude: 122° 24.8' W
T I D A L D A T U M S
Tidal datums at TACOMA, COMMENCEMENT BAY based on:
LENGTH OF SERIES: 19 MONTHS
TIME PERIOD: August 1997 - February 1999
TIDAL EPOCH: 1960-1978
CONTROL TIDE STATION: 9447130 SEATTLE, PUGET SOUND
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
HIGHEST OBSERVED WATER LEVEL (01/04/1998) = 4.416
MEAN HIGHER HIGH WATER MHHW = 3.604
MEAN HIGH WATER MHW = 3.339
MEAN TIDE LEVEL MTL = 2.104
MEAN SEA LEVEL MSL = 2.093
MEAN LOW WATER MLW = 0.869
North American Vertical Datum NAVD88 = 0.815
MEAN LOWER LOW WATER MLLW = 0.000
LOWEST OBSERVED WATER LEVEL (01/03/1999) = -1.109
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
6484 A 1996 5.209 1.870
6484 B 1996 5.325 1.986
6484 C 1996 6.198 2.859
E 406 1965 7.176 3.837
F 406 1965 8.031 4.692
TIDE 22 1933 5.910 2.571
944 6484 POT 101 5.198 1.859
944 6484 POT 925 5.275 1.936
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 6
PUBLICATION DATE: 09/11/2000
Station ID: 9446484 SUPERCEDED DATE: 04/21/2003
Name: TACOMA, COMMENCEMENT BAY
WASHINGTON
NOAA Chart: 18453 Latitude: 47° 16.0' N
USGS Quad: Tacoma North Longitude: 122° 24.8' 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.