U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  7

                                                   PUBLICATION DATE:  06/11/1996
Station ID: 9447130                                SUPERCEDED DATE:   04/21/2003
Name:       SEATTLE, PUGET SOUND                              
            WASHINGTON
NOAA Chart: 18449                                  Latitude:         47° 36.3' N
USGS Quad:  SEATTLE SOUTH                          Longitude:       122° 20.3' W


To reach the tidal bench marks from Seattle Post Office at Third and Union
Streets, proceed west on Union Street for one block, then south on Second Avenue
for three blocks, then west on Madison Street for three blocks, then south on
Alaskan Way to just before the second traffic light (at the intersection of
Columbia Street and Alaskan Way), then turn west into the ferry terminal parking
lot.  The bench marks are near the ferry terminal.  The tide gauge and electric
tape gauge are 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

MONUMENTATION:           Tidal Station disk                        VM#:     1140
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Concrete Retaining Wall


The primary bench mark is 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, 33.5 m
(110 ft) north of the intersection of Western Avenue and Marion Street, and 0.21
m (0.7 ft) from the building's main wall.



                         BENCH MARK STAMPING:  NO 7

MONUMENTATION:           Tidal Station disk                        VM#:     1133
AGENCY:                                                            PID#:  SY0289
SETTING CLASSIFICATION:  Granite Foundation


The bench mark is set vertically in the SW granite cornerstone of the National
Building located on the NE corner of the intersection of Western Avenue and
Madison Street, and 0.91 m (3.0 ft) above the concrete sidewalk surface.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  7

                                                   PUBLICATION DATE:  06/11/1996
Station ID: 9447130                                SUPERCEDED DATE:   04/21/2003
Name:       SEATTLE, PUGET SOUND                              
            WASHINGTON
NOAA Chart: 18449                                  Latitude:         47° 36.3' N
USGS Quad:  SEATTLE SOUTH                          Longitude:       122° 20.3' W


                         T I D A L   B E N C H   M A R K S


                         BENCH MARK STAMPING:  NO 11 1917

MONUMENTATION:           Tidal Station disk                        VM#:     1135
AGENCY:                                                            PID#:  SY0290
SETTING CLASSIFICATION:  Sea Wall


The bench mark is 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.



                         BENCH MARK STAMPING:  14 1922

MONUMENTATION:           Tidal Station disk                        VM#:     1136
AGENCY:                                                            PID#:  SY0286
SETTING CLASSIFICATION:  Concrete Foundation


The bench mark is set vertically in the west face of the Polson Building at 71
Columbia Street near the SE corner of Alaskan Way and Columbia Street, 34.90 m
(114.5 ft) SE of the easternmost Alaskan 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.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  7

                                                   PUBLICATION DATE:  06/11/1996
Station ID: 9447130                                SUPERCEDED DATE:   04/21/2003
Name:       SEATTLE, PUGET SOUND                              
            WASHINGTON
NOAA Chart: 18449                                  Latitude:         47° 36.3' N
USGS Quad:  SEATTLE SOUTH                          Longitude:       122° 20.3' W


                         T I D A L   B E N C H   M A R K S


                         BENCH MARK STAMPING:  16 1922

MONUMENTATION:           Tidal Station disk                        VM#:     1137
AGENCY:                                                            PID#:  SY0284
SETTING CLASSIFICATION:  Sea Wall


The bench mark is set in the top of the sea wall on the west side of Alaskan Way
south of the foot of Yesler Way, 37.19 m (122.0 ft) south of the Yesler
Way/Alaskan Way street post on the west side of Alaskan Way, 12.34 m (40.5 ft)
west of the centerline of Alaskan Way, 7.19 m (23.6 ft) north of the NW corner
of a round water main cover, and 0.15 m (0.5 ft) seaward of a concrete railing.



                         BENCH MARK STAMPING:  17 1922

MONUMENTATION:           Tidal Station disk                        VM#:     1138
AGENCY:                                                            PID#:  SY0283
SETTING CLASSIFICATION:  Brick Foundation


The bench mark is 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.



                         BENCH MARK STAMPING:  7130 D 1989

MONUMENTATION:           Tidal Station disk                        VM#:     1148
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Concrete Footing


The bench mark is set in the concrete support for a metal walkway for the ferry
terminal building, 31.4 m (103 ft) east of the easternmost track of the
railroad, 6.04 m (19.8 ft) south of the centerline of Marion Street, 4.12 m
(13.5 ft) NW of the NW corner of Victors' Sport Bar at 75 Marion Street, and
0.18 m (0.6 ft) east of the west side of the support.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  7

                                                   PUBLICATION DATE:  06/11/1996
Station ID: 9447130                                SUPERCEDED DATE:   04/21/2003
Name:       SEATTLE, PUGET SOUND                              
            WASHINGTON
NOAA Chart: 18449                                  Latitude:         47° 36.3' N
USGS Quad:  SEATTLE SOUTH                          Longitude:       122° 20.3' W


                         T I D A L   B E N C H   M A R K S


                         BENCH MARK STAMPING:  7130 E 1990

MONUMENTATION:           Tidal Station disk                        VM#:     1149
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Concrete Footing


The bench mark is 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 G 1993

MONUMENTATION:           Tidal Station disk                        VM#:     6423
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Sea Wall


The bench mark is set in a sea wall on the west side of Alaskan Way, at the foot
of Columbia Street at the inshore end of the Washington State Ferries Slip on
the south side of the Coleman ferry terminal building between Piers #50 and #51,
7.89 m (25.9 ft) NW of the NW corner of a light post at the west end of Columbia
Street, 9.39 m (30.8 ft) SSW from a walk down walk sign at a pedestrian down
ramp at the ferry terminal, and 0.90 m (3.0 ft) east of a chain link fence.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  5 of  7

                                                   PUBLICATION DATE:  06/11/1996
Station ID: 9447130                                SUPERCEDED DATE:   04/21/2003
Name:       SEATTLE, PUGET SOUND                              
            WASHINGTON
NOAA Chart: 18449                                  Latitude:         47° 36.3' N
USGS Quad:  SEATTLE SOUTH                          Longitude:       122° 20.3' W


                         T I D A L   B E N C H   M A R K S


                         BENCH MARK STAMPING:  7130 H 1993

MONUMENTATION:           Tidal Station disk                        VM#:     6424
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Concrete Footing


The bench mark is 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 Alaskan Way South, 76.2 m (250 ft) SW of Bench Mark 17
1922, 7.93 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  6 of  7

                                                   PUBLICATION DATE:  06/11/1996
Station ID: 9447130                                SUPERCEDED DATE:   04/21/2003
Name:       SEATTLE, PUGET SOUND                              
            WASHINGTON
NOAA Chart: 18449                                  Latitude:         47° 36.3' N
USGS Quad:  SEATTLE SOUTH                          Longitude:       122° 20.3' W


                            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:           1960-1978
     TIDAL EPOCH:           1960-1978
     CONTROL TIDE STATION:   


Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:

     HIGHEST OBSERVED WATER LEVEL (01/27/1983)         =  4.465
     MEAN HIGHER HIGH WATER                     MHHW   =  3.459
     MEAN HIGH WATER                            MHW    =  3.197
     MEAN TIDE LEVEL                            MTL    =  2.030
     MEAN SEA LEVEL                             MSL    =  2.021
     MEAN LOW WATER                             MLW    =  0.863
   * North American Vertical Datum              NAVD88 =  0.765
     MEAN LOWER LOW WATER                       MLLW   =  0.000
     LOWEST  OBSERVED WATER LEVEL (06/20/1951)         = -1.484

   * NAVD is based on elevations published in 1995, and NOS leveling of 1994. 
North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     23 1954                                     6.483    3.286
     NO 7                                        6.636    3.438
     NO 11 1917                                  5.663    2.466
     14 1922                                     6.459    3.261
     16 1922                                     5.709    2.512
     17 1922                                     7.282    4.084
     7130 D 1989                                 6.325    3.127
     7130 E 1990                                 5.880    2.682
     7130 G 1993                                 5.703    2.506
     7130 H 1993                                 6.651    3.453


                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  7 of  7

                                                   PUBLICATION DATE:  06/11/1996
Station ID: 9447130                                SUPERCEDED DATE:   04/21/2003
Name:       SEATTLE, PUGET SOUND                              
            WASHINGTON
NOAA Chart: 18449                                  Latitude:         47° 36.3' N
USGS Quad:  SEATTLE SOUTH                          Longitude:       122° 20.3' 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.