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

                                                   PUBLICATION DATE:  09/10/2001
Station ID: 9459450                                SUPERCEDED DATE:   04/21/2003
Name:       SAND POINT, POPOF ISLAND                          
            ALASKA
NOAA Chart: 16553                                  Latitude:         55° 20.2' N
USGS Quad:  PORT MOLLER (B-2)                      Longitude:       160° 30.1' W


To reach the tidal bench marks from the Airport, proceed on the only road that
leads to town.  Make the first left as you proceed towards town, veer left at
the small boat harbor and follow down until you reach the causeway that leads to
the City Dock.  The gauge is located on the south side of the storage building
on the City Dock.  The bench marks were in the vicinity.


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


                 PRIMARY BENCH MARK STAMPING:  9450 R 1991
                         DESIGNATION:          945 9450 R

MONUMENTATION:           Tidal Station disk                        VM#:     4587
AGENCY:                  National Ocean Survey (NOS)               PID:         
SETTING CLASSIFICATION:  Concrete pier


The primary bench mark is a disk set in the most southerly corner of City Pier,
7.56 m (24.8 ft) NW of SE corner of transit shed, 1.83 m (6.0 ft) SE of SW
corner of transit shed, 1.01 m (3.3 ft) west of NGWLMS plastic protective box,
0.82 m (2.7  ft) NE of SW edge of concrete pier, and 0.61 m (2.0 ft) north of
pier cleat.



                         BENCH MARK STAMPING:  9450 S 1991
                         DESIGNATION:          945 9450 S

MONUMENTATION:           Tidal Station disk                        VM#:     4588
AGENCY:                  National Ocean Service (NOS)              PID:         
SETTING CLASSIFICATION:  Concrete pier


The bench mark is a disk set in the NE corner of the City Pier, 40.54 m (133.0
ft) NE of transit shed, 18.41 m (60.4 ft) SE of the NW edge of the pier, and
0.91 m (3.0 ft) SW of a pier cleat.

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

                                                   PUBLICATION DATE:  09/10/2001
Station ID: 9459450                                SUPERCEDED DATE:   04/21/2003
Name:       SAND POINT, POPOF ISLAND                          
            ALASKA
NOAA Chart: 16553                                  Latitude:         55° 20.2' N
USGS Quad:  PORT MOLLER (B-2)                      Longitude:       160° 30.1' W


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


                         BENCH MARK STAMPING:  9450 T 1991
                         DESIGNATION:          945 9450 T

MONUMENTATION:           Tidal Station disk                        VM#:     4589
AGENCY:                  National Ocean Service (NOS)              PID:         
SETTING CLASSIFICATION:  Boulder


The bench mark is a disk set in top of a large 4 m (12 ft) wide at the base and
1 m (2 ft) at the top, 2 m (8 ft) high irregular shaped boulder, 101 m (333 ft)
NE of the extended centerline of the causeway to the City Pier, 10 m (34 ft) NW
of the center of the dirt road, and 2 m (6 ft) SW of the apparent high water
line.



                         BENCH MARK STAMPING:  9450 U 1991
                         DESIGNATION:          945 9450 U

MONUMENTATION:           Tidal Station disk                        VM#:     4590
AGENCY:                  National Ocean Service (NOS)              PID:         
SETTING CLASSIFICATION:  Concrete ramp


The bench mark is a disk set in the SW corner of a 15 m (50 ft) x 24 m (80 ft)
concrete ramp for the marine travellift located at the NW section of the small
boat harbor, 31 m (102 ft) south of the SE corner of a building used for boat
repair, 0.30 m (1 ft) NE of NE end of steel 10-inch U channel guard rail, and
0.15 m (0.5 ft) NW of easterly edge of the concrete ramp.  

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

                                                   PUBLICATION DATE:  09/10/2001
Station ID: 9459450                                SUPERCEDED DATE:   04/21/2003
Name:       SAND POINT, POPOF ISLAND                          
            ALASKA
NOAA Chart: 16553                                  Latitude:         55° 20.2' N
USGS Quad:  PORT MOLLER (B-2)                      Longitude:       160° 30.1' W


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


                         BENCH MARK STAMPING:  1293 1984
                         DESIGNATION:          945 9450 TIDAL 1293

MONUMENTATION:           Bench Mark disk                           VM#:     4591
AGENCY:                  U.S. Department of Defense (DOD)          PID:         
SETTING CLASSIFICATION:  Steel Pipe


The bench mark is a disk set in top of a 3-inch diameter steel pipe, located at
the centerline of the inshore end of the breakwater for the small boat harbor,
65.14 m (213.7 ft) west of a steel light pole standard, 38.56 m (126.5 ft) SW of
a wooden foot bridge that spans the tidal channel, and 6.19 m (20.3 ft) SW of a
wooden utility pole.



                         BENCH MARK STAMPING:  9450 V 1992
                         DESIGNATION:          945 9450 V

MONUMENTATION:           Tidal Station disk                        VM#:    12593
AGENCY:                  National Ocean Service (NOS)              PID:         
SETTING CLASSIFICATION:  Concrete causeway


The bench mark is a disk set in the concrete causeway on the northeastern corner
of the causeway leading to the city pier, 1.37 m (4.5 ft) NE of the first 0.21 m
x 0.21 m x 1 m (0.7 ft x 0.7 ft x 3 ft) high wooden guard rail post on the north
side of the shore end of causeway, 1.37 m (4.5 ft) NE of NOS witness post, and
0.12 m (0.4 ft) east from the pad-eye where the guard rail cable is attached.

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

                                                   PUBLICATION DATE:  09/10/2001
Station ID: 9459450                                SUPERCEDED DATE:   04/21/2003
Name:       SAND POINT, POPOF ISLAND                          
            ALASKA
NOAA Chart: 16553                                  Latitude:         55° 20.2' N
USGS Quad:  PORT MOLLER (B-2)                      Longitude:       160° 30.1' W


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


                         BENCH MARK STAMPING:  9450 W 1992
                         DESIGNATION:          945 9450 W

MONUMENTATION:           Tidal Station disk                        VM#:    12594
AGENCY:                  National Ocean Service (NOS)              PID:         
SETTING CLASSIFICATION:  Concrete foundation


The bench mark is a disk set in the concrete footing of the D&B Service storage
area, 46 m (150 ft) north of the antenna tower at the harbormaster building,
2.90 m (9.5 ft) east of the SW corner of the D&B service building, 0.30 m (1.0
ft) east of the west side of the roll-up door, and 0.18 m (0.6 ft) north of the
southern edge of the concrete footing.



                         BENCH MARK STAMPING:  9450 X 1992
                         DESIGNATION:          945 9450 X

MONUMENTATION:           Tidal Station disk                        VM#:    12595
AGENCY:                  National Ocean Service (NOS)              PID:         
SETTING CLASSIFICATION:  Concrete vault


The bench mark is a disk set in the SE corner of a 1.22 m (4.0 ft) x 1.22 m (4.0
ft) concrete electric vault near the New Harbor Cafe building under a wooden
deck and stairwell area, 31.4 m (103.0 ft) south of the southern end of the foot
bridge, 10 m (33 ft) north of the apparent high water line, 5.19 m (17.0 ft) SE
of the western-most light pole in the harbor, 0.30 m (1.0 ft) from the western
end, and 0.09 m (0.3 ft) above ground.  

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

                                                   PUBLICATION DATE:  09/10/2001
Station ID: 9459450                                SUPERCEDED DATE:   04/21/2003
Name:       SAND POINT, POPOF ISLAND                          
            ALASKA
NOAA Chart: 16553                                  Latitude:         55° 20.2' N
USGS Quad:  PORT MOLLER (B-2)                      Longitude:       160° 30.1' W


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


                         BENCH MARK STAMPING:  9450 Y 1997
                         DESIGNATION:          945 9450 Y

MONUMENTATION:           Tidal Station disk                        VM#:    13743
AGENCY:                  National Ocean Survey/Service (NOS)       PID:         
SETTING CLASSIFICATION:  Concrete pier


The bench mark is a disk set flush in concrete City Pier on the NE side of the
City Dock Building, 17 m (56 ft) ENE of dock face, 8 m (26 ft) WNW of the east
corner of the building, 4.69 m (15.4 ft) NNE of the north corner of the
building, and 0.24 m (0.8 ft) WSW of ENE edge of the Dock.



                         BENCH MARK STAMPING:  1293-1 1984
                         DESIGNATION:          945 9450 TIDAL 1293-1

MONUMENTATION:           Bench Mark disk                           VM#:    13744
AGENCY:                  U.S. Army Corps of Engineers (USACOE)     PID:         
SETTING CLASSIFICATION:  Pavement


The bench mark is a disk set flush in concrete causeway on the north side,
leading to the city dock, adjacent to the 18th wooden post east of the west end
of a wire rope barrier, 4.54 m (14.9 ft) NNE of centerline of causeway, 0.91 m
(3.0 ft) SSW of a 1-inch stainless steel allthread projecting 0.15 m (0.5 ft)
above ground, 0.76 m (2.5 ft) NNE of the wire rope, 0.40 m (1.3 ft) NNW of the
18th post which has a metal witness sign post attached, and 0.76 m (2.5 ft)
below road level.   

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  6 of  7

                                                   PUBLICATION DATE:  09/10/2001
Station ID: 9459450                                SUPERCEDED DATE:   04/21/2003
Name:       SAND POINT, POPOF ISLAND                          
            ALASKA
NOAA Chart: 16553                                  Latitude:         55° 20.2' N
USGS Quad:  PORT MOLLER (B-2)                      Longitude:       160° 30.1' W


                            T I D A L   D A T U M S 


Tidal datums at SAND POINT, POPOF ISLAND based on:

     LENGTH OF SERIES:      10 YEARS
     TIME PERIOD:           January 1981 - December 1990
     TIDAL EPOCH:           1960-1978
     CONTROL TIDE STATION:  9451600 SITKA


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

     HIGHEST OBSERVED WATER LEVEL (12/31/1986)         =  3.478
     MEAN HIGHER HIGH WATER                     MHHW   =  2.198
     MEAN HIGH WATER                            MHW    =  1.984
     MEAN TIDE LEVEL                            MTL    =  1.192
     MEAN SEA LEVEL                             MSL    =  1.170
     MEAN LOW WATER                             MLW    =  0.399
     MEAN LOWER LOW WATER                       MLLW   =  0.000
     LOWEST  OBSERVED WATER LEVEL (11/15/1993)         = -1.173



Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     9450 R 1991                                 4.540    2.555
     9450 S 1991                                 4.529    2.545
     9450 T 1991                                 3.783    1.799
     9450 U 1991                                 4.344    2.360
     1293 1984                                   3.445    1.460
     9450 V 1992                                 4.127    2.143
     9450 W 1992                                 3.500    1.516
     9450 X 1992                                 3.679    1.695
     9450 Y 1997                                 4.506    2.522
     1293-1 1984                                 3.536    1.552


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

                                                   PUBLICATION DATE:  09/10/2001
Station ID: 9459450                                SUPERCEDED DATE:   04/21/2003
Name:       SAND POINT, POPOF ISLAND                          
            ALASKA
NOAA Chart: 16553                                  Latitude:         55° 20.2' N
USGS Quad:  PORT MOLLER (B-2)                      Longitude:       160° 30.1' 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.