U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  4

                                                   PUBLICATION DATE:  04/20/1984
Station ID: 9446451                                SUPERCEDED DATE:   04/21/2003
Name:       HORSEHEAD BAY, CARR INLET                         
            WASHINGTON
NOAA Chart: 18448                                  Latitude:         47° 18.1' N
USGS Quad:  FOX ISLAND                             Longitude:       122° 40.9' W


To reach the tidal bench marks proceed 1.2 miles (1.9 km) north of Arletta to
the northeasternmost end of Horsehead Bay.  The bench marks are located in the
sea wall around a private residence and the tide gage and staff were located on
the wooden pier on private property.


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


                 PRIMARY BENCH MARK STAMPING:  6451 B 1978

MONUMENTATION:           Survey Disk                               VM#:     9138
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Concrete Sea Wall


The bench mark is set in the top of a concrete sea wall west of a private home
at the northeasternmost end of Horsehead Bay, 68 feet (21 m) north of the NE end
of the pier at a junction with a sidewalk leading to the residence, 13 feet (4
m) south of a brick firepit, and 4 feet (1 m) NW of a large fir tree.  The bench
mark is 1.5 feet (0.5 m) above the beach at the sea wall.



                         BENCH MARK STAMPING:  6451 A 1978

MONUMENTATION:           Survey Disk                               VM#:     9137
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Concrete Sea Wall


The bench mark is set in the top of a concrete sea wall winding north-
southeasterly for 300 feet (91 m), west of the private home at the
northeasternmost end of Horsehead Bay, on the north end of the sea wall, 164
feet (50 m) north of Bench Mark 6451 B 1978, 28 feet (9 m) NW of a 20 foot (6 m)
tree stump, and 3 feet (1 m) above the base of the sea wall.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  4

                                                   PUBLICATION DATE:  04/20/1984
Station ID: 9446451                                SUPERCEDED DATE:   04/21/2003
Name:       HORSEHEAD BAY, CARR INLET                         
            WASHINGTON
NOAA Chart: 18448                                  Latitude:         47° 18.1' N
USGS Quad:  FOX ISLAND                             Longitude:       122° 40.9' W


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


                         BENCH MARK STAMPING:  6451 C 1978

MONUMENTATION:           Survey Disk                               VM#:     9139
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Concrete Sea Wall


The bench mark is set in the top of a concrete sea wall west of a private home
at the northeasternmost end of Horsehead Bay, near the SE end of the sea wall,
164 feet (50 m) SE of Bench Mark 6451 B 1978, and 6 feet (2 m) west of the SE
end of the sea wall.



                         BENCH MARK STAMPING:  6451 D 1978

MONUMENTATION:           Survey Disk                               VM#:     9140
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Concrete Sea Wall


The bench mark is set in the top of a concrete sea wall, 400 feet (122 m) south
of the prominent 400 feet (122 m) long pier leading seaward from the
northeasternmost private home on Horsehead Bay, near the corner of the junction
of a sidewalk cutting through the wall to the beach, 230 feet (70 m) south of
Bench Mark 6451 C 1978, and 20 feet (6 m) SSW of a large fir tree.



                         BENCH MARK STAMPING:  6451 E 1978

MONUMENTATION:           Survey Disk                               VM#:     9141
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Concrete Sea Wall


The bench mark is set in top of a concrete sea wall, 650 feet (198 m) south of
the prominent 400 feet (122 m) pier leading seaward from the northeastern- most
home on Horsehead Bay, 230 feet (70 m) south of Bench Mark 6451 D 1978, and 65
feet (20 m) south of a sidewalk cut in the sea wall.  The bench mark is 7 feet
(2 m) above beach level at the sea wall.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  4

                                                   PUBLICATION DATE:  04/20/1984
Station ID: 9446451                                SUPERCEDED DATE:   04/21/2003
Name:       HORSEHEAD BAY, CARR INLET                         
            WASHINGTON
NOAA Chart: 18448                                  Latitude:         47° 18.1' N
USGS Quad:  FOX ISLAND                             Longitude:       122° 40.9' W


                            T I D A L   D A T U M S 


Tidal datums at HORSEHEAD BAY, CARR INLET based on:

     LENGTH OF SERIES:      1 MONTH
     TIME PERIOD:           MARCH 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 (03/08/1978)         =  14.79
     MEAN HIGHER HIGH WATER                     MHHW   =  13.48
     MEAN HIGH WATER                            MHW    =  12.55
     MEAN TIDE LEVEL                            MTL    =   7.76
     MEAN LOW WATER                             MLW    =   2.97
     MEAN LOWER LOW WATER                       MLLW   =   0.00
     LOWEST  OBSERVED WATER LEVEL (03/06/1978)         =  -0.39



Bench Mark Elevation Information                In FEET above:

     Stamping or Designation                    MLLW        MHW

     6451 B 1978                                17.55      5.00
     6451 A 1978                                17.82      5.27
     6451 C 1978                                17.68      5.13
     6451 D 1978                                17.71      5.16
     6451 E 1978                                17.77      5.22


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

                                                   PUBLICATION DATE:  04/20/1984
Station ID: 9446451                                SUPERCEDED DATE:   04/21/2003
Name:       HORSEHEAD BAY, CARR INLET                         
            WASHINGTON
NOAA Chart: 18448                                  Latitude:         47° 18.1' N
USGS Quad:  FOX ISLAND                             Longitude:       122° 40.9' 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.