U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  6

                                                                                
Station ID: 1630000                                PUBLICATION DATE:  06/27/2017
Name:       APRA HARBOR, GUAM, PACIFIC OCEAN                  
            UNITED STATES OF AMERICA
NOAA Chart: 81054                                  Latitude:         13° 26.3' N
USGS Quad:  APRA HARBOR                            Longitude:       144° 39.2' E


To reach the tidal bench marks, from the Guam airport, travel east on Chalan
Passajeros (Route 10A) for 2.9 km (1.8 mi) until you reach the main gate of the
Naval Station Guam.  Obtain a visitor's pass and continue on Marine Drive for
2.9 km (1.8 mi) until you reach San Luis Road, turn right (east) and follow the
boat channel on your right to its entrance.    The bench marks are located
between Small Boat Channel and Fleet Landing Channel.  The tide house is located
on the east corner of the entrance to the Sunny Cove Marina boat harbor.


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


                 PRIMARY BENCH MARK STAMPING:  NO 6 1949
                         DESIGNATION:          163 0000 TIDAL 6

MONUMENTATION:           Tidal Station disk                        VM#:     1686
AGENCY:                  US Coast and Geodetic Survey (USC&GS)     PID#:  TW0043
SETTING CLASSIFICATION:  Concrete culvert head wall


The primary bench mark is set in top of the S end of a concrete culvert headwall
on the S side of San Luis Road, 95.40 m (313.0 ft) S of bench mark NO 5 1949,
82.30 m (270.0 ft) E of the centerline of Marine Drive, 12.19 m (40.0 ft) S of
the centerline of San Luis Road, and 9.14 m (30.0 ft) N of telephone pole
2-H-22-6-19-2.



                         BENCH MARK STAMPING:  TIDAL BM 13 1975
                         DESIGNATION:          163 0000 TIDAL BM 13

MONUMENTATION:           Tidal Station disk                        VM#:     1690
AGENCY:                  National Ocean Survey (NOS)               PID:         
SETTING CLASSIFICATION:  Concrete apron slab


The bench mark is set in the concrete apron fronting the double door entrance to
the Communication Security Material Issuing office, 70 m (230 ft) NW of the
centerline of the intersection of San Luis Road and Marine Drive, 42 m (139 ft)
W of a fire hydrant, 7 m (24 ft) N of the S wall of the office, and 0.85 m (2.8
ft) E of the office.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  6

                                                                                
Station ID: 1630000                                PUBLICATION DATE:  06/27/2017
Name:       APRA HARBOR, GUAM, PACIFIC OCEAN                  
            UNITED STATES OF AMERICA
NOAA Chart: 81054                                  Latitude:         13° 26.3' N
USGS Quad:  APRA HARBOR                            Longitude:       144° 39.2' E


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


                         BENCH MARK STAMPING:   
                         DESIGNATION:          163 0000 TIDAL 7
                         ALIAS:                TIDAL 7 PIE

MONUMENTATION:           Bolt                                      VM#:     1693
AGENCY:                  Unknown                                   PID#:  TW0044
SETTING CLASSIFICATION:  Concrete culvert head wall


The bench mark is a bolt set flush in the N end of a concrete culvert headwall
at the SW corner of the intersection of Marine Drive and San Luis Road, 21.34 m
(70.0 ft) S of the centerline of San Luis Road, 10.97 m (36.0 ft) W of the
centerline of Marine Drive, and about 4 m (12 ft) N of a protruding concrete
post labeled "Buried Cable".



                         BENCH MARK STAMPING:  0000 P 2006
                         DESIGNATION:          163 0000 P

MONUMENTATION:           Tidal Station disk                        VM#:    17897
AGENCY:                  National Ocean Service (NOS)              PID:         
SETTING CLASSIFICATION:  Concrete steps


The bench mark is set flush in the NE corner of a 2 m x 1 m (6 ft x 4 ft)
landing of steps leading into the Sumay Cove Marina office located the W side of
the Sumay Cove building, 6.90 m (20.0 ft) E of the NE corner of the marina
building,  0.50 m (1.6 ft) NE of the NE end of the stair handrail, 0.20 m (0.5
ft) SE of the NW edge of the 2 m x 1 m (6 ft x 4 ft) concrete landing of the
stairs, and 0.10 m (0.4 ft) NE of the NE end of the SW cinder block retaining
wall.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  6

                                                                                
Station ID: 1630000                                PUBLICATION DATE:  06/27/2017
Name:       APRA HARBOR, GUAM, PACIFIC OCEAN                  
            UNITED STATES OF AMERICA
NOAA Chart: 81054                                  Latitude:         13° 26.3' N
USGS Quad:  APRA HARBOR                            Longitude:       144° 39.2' E


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


                         BENCH MARK STAMPING:  0000 R 2010
                         DESIGNATION:          163 0000 R

MONUMENTATION:           Tidal Station disk                        VM#:    19559
AGENCY:                  National Ocean Service (NOS)              PID:         
SETTING CLASSIFICATION:  Concrete seawall


The bench mark is set in the 1.2 m (4 ft) x 0.9 m (3 ft) concrete seawall on top
of the sheet pile along the Small Boat Channel, 10.40 m (34 ft) N of Slip 13
utility outlet, 10.40 m (34 ft) W of the centerline of the San Luis Road, 2.7 m
(9 ft) SSE of the telephone junction box marked "1C2 9 buried cable", and 6.40 m
(21 ft) W of a water valve cover.



                         BENCH MARK STAMPING:  0000 S 2013
                         DESIGNATION:          163 0000 S

MONUMENTATION:           Tidal Station disk                        VM#:    20669
AGENCY:                  National Ocean Service (NOS)              PID:         
SETTING CLASSIFICATION:  Large concrete sea wall.


The bench mark is a disk set flush in a concrete seawall cap located on the
eastern boundary of Sumay Cove Park, 139.50 m (457.7 ft) SW of the SE corner of
tide station pad, 0.70 m (2.3 ft) NW of the E edge of the concrete seawall cap,
and 0.30 m (1.0 ft) SE of the W edge of the concrete seawall cap.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  6

                                                                                
Station ID: 1630000                                PUBLICATION DATE:  06/27/2017
Name:       APRA HARBOR, GUAM, PACIFIC OCEAN                  
            UNITED STATES OF AMERICA
NOAA Chart: 81054                                  Latitude:         13° 26.3' N
USGS Quad:  APRA HARBOR                            Longitude:       144° 39.2' E


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


                         BENCH MARK STAMPING:  0000 T 2013
                         DESIGNATION:          163 0000 T

MONUMENTATION:           Tidal Station disk                        VM#:    20670
AGENCY:                  National Ocean Service (NOS)              PID:         
SETTING CLASSIFICATION:  Large concrete sea wall.


The bench mark is a disk set flush in a concrete seawall cap located on the
eastern boundary of Sumay Cove Park, 78.30 m (256.9 ft) SSW of the SE corner of
tide station pad, 0.70 m (2.3 ft) NW of the E edge of the concrete seawall cap,
and 0.30 m (1.0 ft) SE of the W edge of the concrete seawall cap.



                         BENCH MARK STAMPING:  0000 U 2013
                         DESIGNATION:          163 0000 U

MONUMENTATION:           Tidal Station disk                        VM#:    20671
AGENCY:                  National Ocean Service (NOS)              PID:         
SETTING CLASSIFICATION:  Large concrete sea wall.


The bench mark is a disk set flush in a concrete seawall cap located on the
eastern boundary of Sumay Cove Park, 22.80 m (74.8 ft) SE of the SE corner of
tide station pad, 0.70 m (2.3 ft) NW of the E edge of the concrete seawall cap,
and 0.30 m (1.0 ft) SE of the W edge of the concrete seawall cap.



                         BENCH MARK STAMPING:  0000 V 2013
                         DESIGNATION:          163 0000 V

MONUMENTATION:           Tidal Station disk                        VM#:    20672
AGENCY:                  National Ocean Service (NOS)              PID:         
SETTING CLASSIFICATION:  Large concrete sea wall.


The bench mark is a disk set flush in a concrete seawall cap located in the NE
corner of Sumay Cove Park, 42.90 m (140.8 ft) NE of the NE corner of tide
station pad, 0.75 m (2.5 ft) S of the N edge of the concrete seawall cap, and
0.25 m (0.8 ft) W of the E edge of the concrete seawall cap.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  5 of  6

                                                                                
Station ID: 1630000                                PUBLICATION DATE:  06/27/2017
Name:       APRA HARBOR, GUAM, PACIFIC OCEAN                  
            UNITED STATES OF AMERICA
NOAA Chart: 81054                                  Latitude:         13° 26.3' N
USGS Quad:  APRA HARBOR                            Longitude:       144° 39.2' E


                            T I D A L   D A T U M S 


Tidal datums at APRA HARBOR, GUAM, PACIFIC OCEAN 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 (08/28/1992)         =  1.309
     MEAN HIGHER HIGH WATER                     MHHW   =  0.715
     MEAN HIGH WATER                            MHW    =  0.678
     MEAN TIDE LEVEL                            MTL    =  0.432
     Guam Vertical Datum of 2004                GUVD04 =  0.423
     MEAN SEA LEVEL                             MSL    =  0.419
     MEAN LOW WATER                             MLW    =  0.185
     MEAN LOWER LOW WATER                       MLLW   =  0.000
     LOWEST  OBSERVED WATER LEVEL (10/24/1972)         = -0.712



Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     NO 6 1949                                   1.957    1.279
     TIDAL BM 13 1975                            3.265    2.587
     163 0000 TIDAL 7                            2.685    2.007
     0000 P 2006                                 2.028    1.350
     0000 R 2010                                 2.093    1.415
     0000 S 2013                                 2.221    1.543
     0000 T 2013                                 2.199    1.521
     0000 U 2013                                 2.182    1.504
     0000 V 2013                                 2.151    1.473


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

                                                                                
Station ID: 1630000                                PUBLICATION DATE:  06/27/2017
Name:       APRA HARBOR, GUAM, PACIFIC OCEAN                  
            UNITED STATES OF AMERICA
NOAA Chart: 81054                                  Latitude:         13° 26.3' N
USGS Quad:  APRA HARBOR                            Longitude:       144° 39.2' E


                             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 any other fixed island datum.

This tide station location has a defined island datum (GUVD04).  Island datums
are specific fixed geodetic datums whose elevation relationship to local MSL
and other tidal datums may not be consistent from one location to another.

Guam Vertical Datum of 2004 (GUVD04) is a fixed datum derived from a
simultaneous, least squares, minimum constraint adjustment of leveling
observations.  Local mean sea level relative to the 1983-2001 National Tidal
Datum Epoch observed at tide station 1630000 at Apra  Harbor, Guam, was held
fixed as the single initial constraint.  GUVD04 replaces all previous height
system as the national standard geodetic reference for heights on Guam.  Bench
mark elevations relative to GUVD04 are available from NGS through the
World Wide Web at National Geodetic Survey.

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 GUVD04 elevation is shown on the Elevations of Tidal Datums Table Referred
to MLLW only when two or more of the bench marks listed have GUVD04 elevations.
The GUVD04 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, GUVD04 bench mark elevations computed indirectly from the tidal
datums elevation table may differ slightly from GUVD04 elevations listed for
each bench mark in the NGS database.