U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of 10

                                                                                
Station ID: 9414290                         PUBLICATION DATE:  04/21/2003
Name:       SAN FRANCISCO                                     
            CA
NOAA Chart: 18649                           Latitude:   37° 48.4' N (  37.80670)
USGS Quad:  SAN FRANCISCO NORTH             Longitude: 122° 27.9' W (-122.46500)


To reach the tidal bench marks, proceed west along U.S. Highway 101 in the
direction of the Golden Gate Bridge, then NW along Crissey Field Avenue (before
the bridge) to the Golden Gate National Park (Presidio).  The bench marks are
located mostly along the coast in the vicinity.  The tide gauge is located on
the NE side of the National Parks Service wharf.


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


                 PRIMARY BENCH MARK STAMPING:  180 1936
                         DESIGNATION:          941 4290  TIDAL 180

MONUMENTATION:           Tidal Station disk                    VM#:          967
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  HT0702
SETTING CLASSIFICATION:  Concrete sea wall                     OPUS PID:        
LATITUDE:   37° 48.3' N (  37.80536)          LONGITUDE: 122° 28.0' W (-122.46675)


The primary bench mark is a disk set in the top of a 1 m (3 ft) high concrete
seawall in Golden Gate National Park at the Gulf of Farallons National Marine
Sanctuary headquarters, 15 m (50 ft) east of the NE corner of the Sanctuaries
building, 6.10 m (20.0 ft) south of the south side of the garage building, and
1.07 m (3.5 ft) north of an angle in wall.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of 10

                                                                                
Station ID: 9414290                         PUBLICATION DATE:  04/21/2003
Name:       SAN FRANCISCO                                     
            CA
NOAA Chart: 18649                           Latitude:   37° 48.4' N (  37.80670)
USGS Quad:  SAN FRANCISCO NORTH             Longitude: 122° 27.9' W (-122.46500)


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


                         BENCH MARK STAMPING:  BM 174 1925
                         DESIGNATION:          941 4290 TIDAL 174
                         ALIAS:                TIDAL 174

MONUMENTATION:           Tidal Station disk                    VM#:          971
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  HT0697
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   37° 48.5' N (  37.80836)          LONGITUDE: 122° 28.3' W (-122.47131)


The bench mark is a disk set in a concrete post flush with the ground inside a
circle of bricks in the pavement, 38.10 m (125.0 ft) west of the extended west
edge of Engineer's Dock where it crosses Marine Drive, at the center of "Y"
between Marine Drive and the road leading SE to Fort Winfield Scott, 12.95 m
(42.5 ft) SW of the fire hydrant, and 8.69 m (28.5 ft) south of the south edge
of an iron manhole cover.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of 10

                                                                                
Station ID: 9414290                         PUBLICATION DATE:  04/21/2003
Name:       SAN FRANCISCO                                     
            CA
NOAA Chart: 18649                           Latitude:   37° 48.4' N (  37.80670)
USGS Quad:  SAN FRANCISCO NORTH             Longitude: 122° 27.9' W (-122.46500)


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


                         BENCH MARK STAMPING:  BM 176 1925
                         DESIGNATION:          941 4290 TIDAL 176
                         ALIAS:                TIDAL 176

MONUMENTATION:           Tidal Station disk                    VM#:          972
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  HT0705
SETTING CLASSIFICATION:  Concrete step                         OPUS PID:        
LATITUDE:   37° 48.2' N (  37.80350)          LONGITUDE: 122° 28.0' W (-122.46725)


The bench mark is a disk set in the west end of the lowest concrete step at the
main entrance to the porch of the building at No. 651 Mason Street, 29.87 m
(98.0 ft) SE of the intersection of Crissey Field Avenue and Mason Street, 15.24
m (50.0 ft) south of the centerline of Mason Street, and 0.21 m (0.7 ft) above
sidewalk.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of 10

                                                                                
Station ID: 9414290                         PUBLICATION DATE:  04/21/2003
Name:       SAN FRANCISCO                                     
            CA
NOAA Chart: 18649                           Latitude:   37° 48.4' N (  37.80670)
USGS Quad:  SAN FRANCISCO NORTH             Longitude: 122° 27.9' W (-122.46500)


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


                         BENCH MARK STAMPING:  181 1945
                         DESIGNATION:          941 4290 TIDAL 181
                         ALIAS:                TIDAL 181

MONUMENTATION:           Tidal Station disk                    VM#:          973
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  HT0701
SETTING CLASSIFICATION:  Sea wall                              OPUS PID:        
LATITUDE:   37° 48.4' N (  37.80597)          LONGITUDE: 122° 28.1' W (-122.46750)


The bench mark is a disk set in NW corner of a sea wall at the Golden Gate
National Park at the Gulf of Farallons National Marine Sanctuary headquarters,
62 m (204 ft) west of the inshore end of the pier, 45.87 m (150.5 ft) NW of a
flag pole, 21.64 m (71.0 ft) NE of the north corner of Building S.F. 19.4 (paint
shop and storage building), and 1.22 m (4.0 ft) above ground. 

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  5 of 10

                                                                                
Station ID: 9414290                         PUBLICATION DATE:  04/21/2003
Name:       SAN FRANCISCO                                     
            CA
NOAA Chart: 18649                           Latitude:   37° 48.4' N (  37.80670)
USGS Quad:  SAN FRANCISCO NORTH             Longitude: 122° 27.9' W (-122.46500)


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


                         BENCH MARK STAMPING:  NO 2 1948
                         DESIGNATION:          CLARK RM 2
                         ALIAS:                941 4290 TIDAL 183

MONUMENTATION:           Triangulation Station disk            VM#:          975
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  HT0700
SETTING CLASSIFICATION:  Sea wall                              OPUS PID:        
LATITUDE:   37° 48.5' N (  37.80856)          LONGITUDE: 122° 28.2' W (-122.47078)


The bench mark is a disk set flush in the top of a sea wall west of the public
fishing pier, 11.43 m (37.5 ft) west of the west edge of the pier, 8.08 m (26.5
ft) NE of the NE corner of corrugated iron building No. 985, and about 0.91 m
(3.0 ft) above ground.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  6 of 10

                                                                                
Station ID: 9414290                         PUBLICATION DATE:  04/21/2003
Name:       SAN FRANCISCO                                     
            CA
NOAA Chart: 18649                           Latitude:   37° 48.4' N (  37.80670)
USGS Quad:  SAN FRANCISCO NORTH             Longitude: 122° 27.9' W (-122.46500)


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


                         BENCH MARK STAMPING:  CLARK 1948
                         DESIGNATION:          CLARK
                         ALIAS:                941 4290 TIDAL 185

MONUMENTATION:           Triangulation Station disk            VM#:          976
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  HT0698
SETTING CLASSIFICATION:  Concrete sea wall                     OPUS PID:        
LATITUDE:   37° 48.5' N (  37.80861)          LONGITUDE: 122° 28.3' W (-122.47094)


The bench mark is a disk set in the top of a concrete sea wall west of the
public fishing pier, about 549 m (1800 ft) NW of the Gulf of Farallons National
Marine Sanctuary headquarters in Golden Gate National Park, 24.23 m (79.5 ft)
west of the west edge of the pier, 6.86 m (22.5 ft) NE of the NW corner of
corrugated iron building No. 985, 3.05 m (10.0 ft) west of the NW corner of a
stucco paint locker building, and 1.07 m (3.5 ft) above ground.



                         BENCH MARK STAMPING:  4290 K 1976
                         DESIGNATION:          941 4290 K TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:          978
AGENCY:                  National Ocean Service (NOS)          IDB PID#:  HT2255
SETTING CLASSIFICATION:  Bedrock                               OPUS PID:        
LATITUDE:   37° 48.5' N (  37.80842)          LONGITUDE: 122° 28.3' W (-122.47147)


The bench mark is a disk set vertically in bedrock on the south side of Marine
Drive, 24 m (79 ft) SSW of the SE corner of the National Park Service building #
T989, 14.69 m (48.2 ft) NW of bench mark BM 174 1925, and 2.44 m (8.0 ft) south
of the road curb.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  7 of 10

                                                                                
Station ID: 9414290                         PUBLICATION DATE:  04/21/2003
Name:       SAN FRANCISCO                                     
            CA
NOAA Chart: 18649                           Latitude:   37° 48.4' N (  37.80670)
USGS Quad:  SAN FRANCISCO NORTH             Longitude: 122° 27.9' W (-122.46500)


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


                         BENCH MARK STAMPING:  4290 L 1976
                         DESIGNATION:          941 4290 L TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:          979
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  HT2253
SETTING CLASSIFICATION:  Bedrock                               OPUS PID:        
LATITUDE:   37° 48.5' N (  37.80883)          LONGITUDE: 122° 28.4' W (-122.47283)


The bench mark is a disk set in bedrock on the south side of Marine Drive, 114 m
(375 ft) west of the National Park Service building # T989, 15.70 m (51.5 ft) SE
of the eastern-most concrete and steel safety chain stanchion on the seawall,
7.77 m (25.5 ft) from the centerline of Marine Drive, and 1.22 m (4 ft) above
street level.



                         BENCH MARK STAMPING:  4290 M 1982
                         DESIGNATION:          941 4290 M TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:          980
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  HT3538
SETTING CLASSIFICATION:  Concrete foundation                   OPUS PID:        
LATITUDE:   37° 48.2' N (  37.80328)          LONGITUDE: 122° 28.0' W (-122.46667)


The bench mark is a disk set flush in concrete foundation in front of Stilwell
Hall (buiding # 650) on Mason Street, 27.34 m (89.7 ft) south of the centerline
of Mason street, 10.30 m (33.8 ft) east of the NE corner of the west wing of the
Stilwell Hall, 6.07 m (19.9 ft) west of the west edge of the sidewalk leading to
the entrance of Stilwell Hall, 0.30 m (1.0 ft) SE of the NW corner of the
foundation, and 0.12 m (0.4 ft) above ground level.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  8 of 10

                                                                                
Station ID: 9414290                         PUBLICATION DATE:  04/21/2003
Name:       SAN FRANCISCO                                     
            CA
NOAA Chart: 18649                           Latitude:   37° 48.4' N (  37.80670)
USGS Quad:  SAN FRANCISCO NORTH             Longitude: 122° 27.9' W (-122.46500)


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


                         BENCH MARK STAMPING:  BM 175 1925
                         DESIGNATION:          941 4290  TIDAL 175
                         ALIAS:                TIDAL 175

MONUMENTATION:           Tidal Station disk                    VM#:         1829
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  HT0696
SETTING CLASSIFICATION:  Sea wall                              OPUS PID:        
LATITUDE:   37° 48.5' N (  37.80886)          LONGITUDE: 122° 28.3' W (-122.47206)


The bench mark is a disk set in top surface of the sea wall, near the National
Park Service building at the intersection of the pavement and the seawall, 65.23
m (214.0 ft) NE of bench mark 4290 L 1976, 58.67 m (192.5 ft) west from the NW
corner of the National Park Service building, 28.90 m (94.8 ft) WNW of the
northern-most post of pedestrian gate, 6.86 m (22.5 ft) north of the centerline
of  Marine Drive, and 0.73 m (2.4 ft) south from the north edge of the sea wall.



                         BENCH MARK STAMPING:  4290 N 1995
                         DESIGNATION:          941 4290 N

MONUMENTATION:           Tidal Station disk                    VM#:        15436
AGENCY:                  National Ocean Service (NOS)          IDB PID#:  AE5209
SETTING CLASSIFICATION:  Concrete sea wall                     OPUS PID:        
LATITUDE:   37° 48.3' N (  37.80561)          LONGITUDE: 122° 28.0' W (-122.46692)


The bench mark is a disk set in a concrete seawall in Golden Gate National Park
at the Gulf of Farallons National Marine Sanctuary headquarters, near an inshore
end of a walkway leading to a pier, 13.70 m  (44.9 ft) north of bottom of stairs
leading to the Sanctuary building, 3.96 m (13.0 ft) east of a step in seawall,
and 3.20 m (10.5 ft) west of the center of the walkway.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  9 of 10

                                                                                
Station ID: 9414290                         PUBLICATION DATE:  04/21/2003
Name:       SAN FRANCISCO                                     
            CA
NOAA Chart: 18649                           Latitude:   37° 48.4' N (  37.80670)
USGS Quad:  SAN FRANCISCO NORTH             Longitude: 122° 27.9' W (-122.46500)


                            T I D A L   D A T U M S 


Tidal datums at SAN FRANCISCO 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 (01/27/1983)         =  2.640
     MEAN HIGHER HIGH WATER                     MHHW   =  1.780
     MEAN HIGH WATER                            MHW    =  1.595
     MEAN TIDE LEVEL                            MTL    =  0.970
     MEAN SEA LEVEL                             MSL    =  0.951
     MEAN LOW WATER                             MLW    =  0.346
     MEAN LOWER LOW WATER                       MLLW   =  0.000
     North American Vertical Datum              NAVD88 = -0.018
     LOWEST  OBSERVED WATER LEVEL (12/17/1933)         = -0.877

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     180 1936                                    3.972    2.378
     BM 174 1925                                 5.013    3.418
     BM 176 1925                                 4.814    3.219
     181 1945                                    3.987    2.392
     NO 2 1948                                   4.221    2.626
     CLARK 1948                                  4.233    2.639
     4290 K 1976                                 5.828    4.234
     4290 L 1976                                 6.620    5.025
     4290 M 1982                                 3.705    2.111
     BM 175 1925                                 4.160    2.566
     4290 N 1995                                 3.646    2.051


                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page 10 of 10

                                                                                
Station ID: 9414290                         PUBLICATION DATE:  04/21/2003
Name:       SAN FRANCISCO                                     
            CA
NOAA Chart: 18649                           Latitude:   37° 48.4' N (  37.80670)
USGS Quad:  SAN FRANCISCO NORTH             Longitude: 122° 27.9' W (-122.46500)


                             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.