U.S. DEPARTMENT OF COMMERCE
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National Ocean Service
Datums Page Page 1 of 8
Station ID: 9447130 PUBLICATION DATE: 04/21/2003
Name: SEATTLE, PUGET SOUND
WA
NOAA Chart: 18449 Latitude: 47° 36.3' N ( 47.60500)
USGS Quad: SEATTLE SOUTH Longitude: 122° 20.3' W (-122.33800)
To reach the tidal bench marks from the Seattle Post Office at Third and Union
Streets, proceed west on Union Street for one block, then right (south) on
Second Avenue for three blocks, then right (west) on Madison Street for three
blocks, then left (south) on Alaskan Way to just before the second traffic light
(at the intersection of Columbia Street and Alaskan Way), then turn right (west)
into the ferry terminal parking lot. The tidal bench marks are near the ferry
terminal. The tide guage is located in the ferry terminal building in a storage
room adjacent to and north of the Bremerton Ferry loading ramp.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 23 1954
DESIGNATION: 944 7130 TIDAL 23
MONUMENTATION: Tidal Station disk VM#: 1140
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Concrete bulkhead OPUS PID:
LATITUDE: 47° 36.2' N ( 47.60381) LONGITUDE: 122° 20.2' W (-122.33667)
The primary bench mark is a disk set flush in the top of the concrete bulkhead
retaining wall projecting out from the foundation on the west side of the
Federal Office Building, on the north side of the auto-garage entrance, 34 m
(110 ft) north of the intersection of Western Avenue and Marion Street, and 0.21
m (0.7 ft) from the buildings main wall.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 8
Station ID: 9447130 PUBLICATION DATE: 04/21/2003
Name: SEATTLE, PUGET SOUND
WA
NOAA Chart: 18449 Latitude: 47° 36.3' N ( 47.60500)
USGS Quad: SEATTLE SOUTH Longitude: 122° 20.3' W (-122.33800)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 7
DESIGNATION: 944 7130 TIDAL 7
MONUMENTATION: Tidal Station disk VM#: 1133
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: SY0289
SETTING CLASSIFICATION: Granite wall OPUS PID:
LATITUDE: 47° 36.3' N ( 47.60442) LONGITUDE: 122° 20.2' W (-122.33731)
The bench mark is a disk set vertically in the SW granite cornerstone of the
National Building located on the NE corner of the intersection of the Western
Avenue and Madison Street, and is 0.91 m (3.0 ft) above the concrete sidewalk.
BENCH MARK STAMPING: NO 11 1917
DESIGNATION: 944 7130 TIDAL 11
ALIAS: 11
MONUMENTATION: Tidal Station disk VM#: 1135
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: SY0290
SETTING CLASSIFICATION: Concrete deck OPUS PID:
LATITUDE: 47° 36.2' N ( 47.60378) LONGITUDE: 122° 20.3' W (-122.33867)
The bench mark is a disk set in a concrete deck nearly opposite the foot of
Madison Avenue, between Pier 53 (Black Ball Line) on the south and Pier 54
(Ivars Fish Bar) on the north, 12.34 m (40.5 ft) NE of the Fire Station N0 5
office door, 7.93 m (26.0 ft) east of the NE corner of Fire Station N0 5, 3.66 m
(12.0 ft) south of the south end of the concrete railing, and 0.03 m (0.1 ft)
below grade in a NGS access cover.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 8
Station ID: 9447130 PUBLICATION DATE: 04/21/2003
Name: SEATTLE, PUGET SOUND
WA
NOAA Chart: 18449 Latitude: 47° 36.3' N ( 47.60500)
USGS Quad: SEATTLE SOUTH Longitude: 122° 20.3' W (-122.33800)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 14 1922
DESIGNATION: 944 7130 TIDAL 14
MONUMENTATION: Tidal Station disk VM#: 1136
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: SY0286
SETTING CLASSIFICATION: Building OPUS PID:
LATITUDE: 47° 36.1' N ( 47.60244) LONGITUDE: 122° 20.2' W (-122.33653)
The bench mark is a disk set vertically in the west face of the Polson Building
at 71 Columbia Street near the SE corner of the Alaskan Way and Columbia Street,
34.90 m (114.5 ft) SE of the easternmost Alaska Way/Columbia Street post, 23.17
m (76.0 ft) west of the centerline of the north entrance to the Polson Building,
0.34 m (1.1 feet) south of the NW corner of the Polson Building, and 0.73 m (2.4
ft) above the pavement.
BENCH MARK STAMPING: 17 1922
DESIGNATION: 944 7130 TIDAL 17
MONUMENTATION: Tidal Station disk VM#: 1138
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: SY0283
SETTING CLASSIFICATION: Building OPUS PID:
LATITUDE: 47° 36.1' N ( 47.60122) LONGITUDE: 122° 20.1' W (-122.33556)
The bench mark is a disk set vertically in the west face of the north end of the
Prudential Building at 112 South Alaskan Way, between Yesler Way and Washington
Street, squarely in the center of the brick face of the pillar formed by the
north wall of the building.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 8
Station ID: 9447130 PUBLICATION DATE: 04/21/2003
Name: SEATTLE, PUGET SOUND
WA
NOAA Chart: 18449 Latitude: 47° 36.3' N ( 47.60500)
USGS Quad: SEATTLE SOUTH Longitude: 122° 20.3' W (-122.33800)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 7130 E 1990
DESIGNATION: 944 7130 E
MONUMENTATION: Tidal Station disk VM#: 1149
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete footing OPUS PID:
LATITUDE: 47° 36.2' N ( 47.60258) LONGITUDE: 122° 20.4' W (-122.33925)
The bench mark is a disk set in the SE side of the base of the yellow and white
concrete pillar on the north side of the entrance to the Bremerton Ferry
Terminal, 17.53 m (57.5 ft) north of the south guard rail at the ferry entrance,
11.22 m (36.8 ft) east of the west guard rail, 2.32 m (7.6 ft) SSE of the SE
corner of the Ferry Terminal building, and 0.15 m (0.5 ft) above grade.
BENCH MARK STAMPING: 7130 H 1993
DESIGNATION: 944 7130 H
MONUMENTATION: Tidal Station disk VM#: 6424
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete footing OPUS PID:
LATITUDE: 47° 36.3' N ( 47.60500) LONGITUDE: 122° 20.3' W (-122.33800)
The bench mark is a disk set in the concrete base of the most NE (marked 100) of
four concrete supports (for Highway 99) that surround the intersection of South
Washington Street and Alaska Way South, 76.20 m (250.0 ft) SW of bench mark 17
1922, 8 m (26 ft) north of the centerline of South Washington Street, 0.37 m
(1.2 ft) west of the four metal pipes, and 1.10 m (3.6 ft) above ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 8
Station ID: 9447130 PUBLICATION DATE: 04/21/2003
Name: SEATTLE, PUGET SOUND
WA
NOAA Chart: 18449 Latitude: 47° 36.3' N ( 47.60500)
USGS Quad: SEATTLE SOUTH Longitude: 122° 20.3' W (-122.33800)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 7130 M 2002
DESIGNATION: 944 7130 M
MONUMENTATION: Tidal Station disk VM#: 16689
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Sea wall OPUS PID:
LATITUDE: 47° 36.1' N ( 47.60086) LONGITUDE: 122° 20.2' W (-122.33622)
The bench mark is a disk set in top of a seawall on Alaska Way South, just west
of second upright north of south end of concrete guard rail, 8 m (26 ft) south
of street lamp 105, 4.40 m (14.4 ft) west of the curb of south side of Alaska
Way South, 2.40 m (7.9 ft) north of south end of concrete guardrail, and 0.18 m
(0.6 ft) east of the face of the seawall.
BENCH MARK STAMPING: 7130 N 2002
DESIGNATION: 944 7130 N
MONUMENTATION: Tidal Station disk VM#: 16690
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Loading dock OPUS PID:
LATITUDE: 47° 36.2' N ( 47.60339) LONGITUDE: 122° 20.3' W (-122.33750)
The bench mark is a disk set in the SE corner of the elevated loading dock on
south side of Maritime Building, in 900 block of Alaska Way South, 4.36 m (14.3
ft) north of SW corner of the building, 2.62 m (8.6 ft) east of west edge of the
loading dock, 2.06 m (6.8 ft) south of south side of door to 902 Alaska Way
South, and 0.60 m (2.0 ft) above the parking lot grade.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 8
Station ID: 9447130 PUBLICATION DATE: 04/21/2003
Name: SEATTLE, PUGET SOUND
WA
NOAA Chart: 18449 Latitude: 47° 36.3' N ( 47.60500)
USGS Quad: SEATTLE SOUTH Longitude: 122° 20.3' W (-122.33800)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: DAVE 1998
DESIGNATION: 944 7130 DAVE
MONUMENTATION: Bench Mark disk VM#: 16691
AGENCY: Washington State Department of
Transportation IDB PID#:
SETTING CLASSIFICATION: Pier OPUS PID#: BBDL91
LATITUDE: 47° 36.1' N ( 47.60181) LONGITUDE: 122° 20.3' W (-122.33867)
The bench mark is a disk set in SW corner of pier, 12.70 m (41.7 ft) east of SE
corner of pier, 6.70 m (22.0 ft) SW of a 12" drain in the center of a car lane,
1.1 m (3.6 ft) north of south pier face, and 0.25 m (0.8 ft) below pier grade,
in a 4" PVC hand hole.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 7 of 8
Station ID: 9447130 PUBLICATION DATE: 04/21/2003
Name: SEATTLE, PUGET SOUND
WA
NOAA Chart: 18449 Latitude: 47° 36.3' N ( 47.60500)
USGS Quad: SEATTLE SOUTH Longitude: 122° 20.3' W (-122.33800)
T I D A L D A T U M S
Tidal datums at SEATTLE, PUGET SOUND based on:
LENGTH OF SERIES: 19 Years
TIME PERIOD: January 1983 - December 2001
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION:
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
HIGHEST OBSERVED WATER LEVEL (01/27/1983) = 4.415
MEAN HIGHER HIGH WATER MHHW = 3.462
MEAN HIGH WATER MHW = 3.198
MEAN TIDE LEVEL MTL = 2.031
MEAN SEA LEVEL MSL = 2.023
MEAN LOW WATER MLW = 0.864
North American Vertical Datum NAVD88 = 0.715
MEAN LOWER LOW WATER MLLW = 0.000
LOWEST OBSERVED WATER LEVEL (01/04/1916) = -1.535
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
23 1954 6.432 3.233
NO 7 6.582 3.383
NO 11 1917 5.610 2.411
14 1922 6.408 3.210
17 1922 7.231 4.033
7130 E 1990 5.828 2.630
7130 H 1993 6.601 3.402
7130 M 2002 5.645 2.447
7130 N 2002 6.014 2.816
DAVE 1998 5.465 2.267
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 8 of 8
Station ID: 9447130 PUBLICATION DATE: 04/21/2003
Name: SEATTLE, PUGET SOUND
WA
NOAA Chart: 18449 Latitude: 47° 36.3' N ( 47.60500)
USGS Quad: SEATTLE SOUTH Longitude: 122° 20.3' W (-122.33800)
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.