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

                                                                                
Station ID: 9414358                         PUBLICATION DATE:  04/30/2012
Name:       HUNTERS POINT, S.F. BAY                           
            CA
NOAA Chart: 18649                           Latitude:   37° 43.8' N (  37.73000)
USGS Quad:  HUNTERS POINT                   Longitude: 122° 21.4' W (-122.35700)


To reach the tidal bench marks from I-280 and U.S. Highway 101 interchange
proceed 2.2 km (1.4 mi) south to Bayshore Blvd., Third Street exit, left onto
Third Street, north 2.9 km (1.8 mi) to Evans Street, right turn on Evans Street,
1.1 km (0.7 mi) SE on Evans Street, one block south on Evans Street to Fairfax
Street, right on Hunters Point Boulevard, 0.3 km (0.2 mi) after left turn on
Innes Avenue and then 0.6 km (0.4 mi) to entrance to guard house with dry dock
area at bottom of hill.  The tide gage was located 15.24 m (50.0 ft) NW of NW
corner of drydock No. 2 and the staff was located on an adjacent pier.


                         T I D A L   B E N C H   M A R K S
                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  6

                                                                                
Station ID: 9414358                         PUBLICATION DATE:  04/30/2012
Name:       HUNTERS POINT, S.F. BAY                           
            CA
NOAA Chart: 18649                           Latitude:   37° 43.8' N (  37.73000)
USGS Quad:  HUNTERS POINT                   Longitude: 122° 21.4' W (-122.35700)


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


                 PRIMARY BENCH MARK STAMPING:  HUNTERS POINT BM 2 1917
                         DESIGNATION:          TIDAL 2

MONUMENTATION:           Bench Mark disk                       VM#:         8098
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  HT0619
SETTING CLASSIFICATION:  Set vertically in west wall           OPUS PID:        
LATITUDE:   37° 43.8' N (  37.73000)          LONGITUDE: 122° 21.5' W (-122.35800)


The primary bench mark is a disk set vertically in the west wall at the NW
corner of the small brick pump house (Building No. 204) between drydocks No. 2
and 3, 31 m (100 ft) east of center of capstan at SE corner of drydock No. 3, 20
m (64 ft) east of SE corner of south end of caisson of drydock No. 2, and 0.15 m
(0.5 ft) above the paved ground.

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

                                                                                
Station ID: 9414358                         PUBLICATION DATE:  04/30/2012
Name:       HUNTERS POINT, S.F. BAY                           
            CA
NOAA Chart: 18649                           Latitude:   37° 43.8' N (  37.73000)
USGS Quad:  HUNTERS POINT                   Longitude: 122° 21.4' W (-122.35700)


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


                         BENCH MARK STAMPING:  HUNTERS POINT BM 3 1917
                         DESIGNATION:          TIDAL 3

MONUMENTATION:           Bench Mark disk                       VM#:         8099
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  HT0618
SETTING CLASSIFICATION:  Set vertically on south wall          OPUS PID:        
LATITUDE:   37° 43.8' N (  37.73000)          LONGITUDE: 122° 21.5' W (-122.35800)


The bench mark is a disk set vertically in the south wall of brick boiler room C
of building No. 205, between drydocks No. 2 and 3, 30 m (100 ft) east of SW
corner of boiler room building, 11 m (35 ft) north of north edge of drydock No.
2 and 5 m (15 ft) east of the centerline of the door at center of the boiler
room wall.



                         BENCH MARK STAMPING:  4 1941
                         DESIGNATION:          4

MONUMENTATION:           Bench Mark disk                       VM#:         8100
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  HT0616
SETTING CLASSIFICATION:  Concrete platform                     OPUS PID:        
LATITUDE:   37° 43.8' N (  37.73000)          LONGITUDE: 122° 21.5' W (-122.35800)


The bench mark is a disk set in the top of the SE corner of the concrete loading
platform at the NE corner of a large concrete machine shop (Building No. 231),
29 m (96 ft) south of the south side of drydock No. 2, 0.15 m (0.5 ft) north of
the north wall of the building, and 1.04 m (3.4 ft) above the pavement.

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

                                                                                
Station ID: 9414358                         PUBLICATION DATE:  04/30/2012
Name:       HUNTERS POINT, S.F. BAY                           
            CA
NOAA Chart: 18649                           Latitude:   37° 43.8' N (  37.73000)
USGS Quad:  HUNTERS POINT                   Longitude: 122° 21.4' W (-122.35700)


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


                         BENCH MARK STAMPING:  5 1941
                         DESIGNATION:          5

MONUMENTATION:           Bench Mark disk                       VM#:         8101
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  HT0615
SETTING CLASSIFICATION:  Concrete platform                     OPUS PID:        
LATITUDE:   37° 43.8' N (  37.73000)          LONGITUDE: 122° 21.5' W (-122.35800)


The bench mark is a disk set in the top of the NW corner of the concrete loading
platform at the SW corner of the large concrete machine shop (Building No. 231),
79 m (260 ft) south of drydock No. 2, 0.15 m (0.5 ft) south of the south wall of
the building, and 0.9 m (3 ft) above the pavement.

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

                                                                                
Station ID: 9414358                         PUBLICATION DATE:  04/30/2012
Name:       HUNTERS POINT, S.F. BAY                           
            CA
NOAA Chart: 18649                           Latitude:   37° 43.8' N (  37.73000)
USGS Quad:  HUNTERS POINT                   Longitude: 122° 21.4' W (-122.35700)


                            T I D A L   D A T U M S 


Tidal datums at HUNTERS POINT, S.F. BAY based on:

     LENGTH OF SERIES:      2 MONTHS
     TIME PERIOD:           July 1979 - August 1979
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  9414750 ALAMEDA, SAN FRANCISCO BAY


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

     MEAN HIGHER HIGH WATER                     MHHW   =  2.072
     MEAN HIGH WATER                            MHW    =  1.883
     MEAN TIDE LEVEL                            MTL    =  1.116
     MEAN SEA LEVEL                             MSL    =  1.085
     MEAN LOW WATER                             MLW    =  0.348
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     HUNTERS POINT BM 2 1917                     3.745    1.862
     HUNTERS POINT BM 3 1917                     3.824    1.941
     4 1941                                      4.796    2.913
     5 1941                                      4.812    2.929


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

                                                                                
Station ID: 9414358                         PUBLICATION DATE:  04/30/2012
Name:       HUNTERS POINT, S.F. BAY                           
            CA
NOAA Chart: 18649                           Latitude:   37° 43.8' N (  37.73000)
USGS Quad:  HUNTERS POINT                   Longitude: 122° 21.4' W (-122.35700)


                             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.