Superseded Bench Mark Sheet for 9414509, Dumbarton Bridge CA

Present Epoch

Printable version

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  5

                                                   PUBLICATION DATE:  11/08/2000
Station ID: 9414509                                SUPERCEDED DATE:   04/21/2003
Name:       DUMBARTON BRIDGE, SAN FRANCISCO BAY               
            CALIFORNIA
NOAA Chart: 18651                                  Latitude:         37° 30.4' N
USGS Quad:  NEWARK                                 Longitude:       122°  6.9' W


To reach the tidal bench marks from I-80, take the Dumbarton Bridge West exit,
then turn left on Thorton Avenue West, follow the signs to the wildlife refuge
which will lead to a frontage road and then to the bridge.  The bench marks are
along the roadway of the bridge.  Special use permit or authorization is
required to visit the bench marks or the station. The tide gage was located at
the SW end of the old State Road 84 bridge.


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


                 PRIMARY BENCH MARK STAMPING:  U 553 1956
                         DESIGNATION:          U 553

MONUMENTATION:           Tidal Station disk                        VM#:     8150
AGENCY:                  US Coast & Geodetic Survey (USC&GS)       PID#:  HT0308
SETTING CLASSIFICATION:  Concrete curb


The primary bench mark is a disk set in top of the concrete curb along the old
Dumbarton bridge, at the SW end, 9 m (30 ft) SW of the tide house, 3.51 m (11.5
ft) SE of the centerline of the road, 0.30 m (1 ft) NE of the stairs leading to
fishing pier, and 0.25 m (0.8 ft) above the road.



                         BENCH MARK STAMPING:  V 553 1956
                         DESIGNATION:          V 553

MONUMENTATION:           Tidal Station disk                        VM#:     8151
AGENCY:                  US Coast & Geodetic Survey (USC&GS)       PID#:  HT0309
SETTING CLASSIFICATION:  Concrete curb


The bench mark is a disk set in top of the concrete curb over BENT 117 on the SE
side of old Dumbarton Bridge, 54.10 m (177.5 ft) SW of the NE end of the bridge,
3.50 m (11.5 ft) SE of the centerline of the bridge, and 0.25 m (0.8 ft) above
the road.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  5

                                                   PUBLICATION DATE:  11/08/2000
Station ID: 9414509                                SUPERCEDED DATE:   04/21/2003
Name:       DUMBARTON BRIDGE, SAN FRANCISCO BAY               
            CALIFORNIA
NOAA Chart: 18651                                  Latitude:         37° 30.4' N
USGS Quad:  NEWARK                                 Longitude:       122°  6.9' W


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


                         BENCH MARK STAMPING:  4509 G 1983
                         DESIGNATION:          941 4509 G

MONUMENTATION:           Tidal Station disk                        VM#:     8153
AGENCY:                  National Ocean Survey (NOS)               PID:         
SETTING CLASSIFICATION:  Galvanized steel rod


The bench mark is a disk located on the eastern edge of a parking lot at the SE
corner of the old Dumbarton bridge, 15.54 m (51.0 ft) SE of the centerline of
road which leads to the old Dumbarton bridge. The bench mark is set 9 cm (0.3
ft) above ground, crimped to a galvanized rod driven to a depth of 14.6 m (48
ft), and encased in a 4 inch PVC pipe.



                         BENCH MARK STAMPING:  4509 H 1983
                         DESIGNATION:          941 4509 H 1983

MONUMENTATION:           Tidal Station disk                        VM#:     8154
AGENCY:                  National Ocean Survey/Service (NOS)       PID:         
SETTING CLASSIFICATION:  Galvanized steel rod


The bench mark is a disk located on the south side of the road that leads to the
pier, 274 m (900 ft) NE of the shore end of the pier, 10 m (34 ft) SE of the
centerline of the road, 4.27 m (14.0 ft) east of the guard rail, and 0.12 m (0.4
ft) north of an orange witness post. The bench mark is set 9 cm (0.3 ft) below
ground, crimped to a galvenized rod driven to a depth of 14.6 m (48 ft), and
encased in a 4-inch PVC pipe with black cover.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  5

                                                   PUBLICATION DATE:  11/08/2000
Station ID: 9414509                                SUPERCEDED DATE:   04/21/2003
Name:       DUMBARTON BRIDGE, SAN FRANCISCO BAY               
            CALIFORNIA
NOAA Chart: 18651                                  Latitude:         37° 30.4' N
USGS Quad:  NEWARK                                 Longitude:       122°  6.9' W


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


                         BENCH MARK STAMPING:  4509 K 1996
                         DESIGNATION:          941 4509 K 1996

MONUMENTATION:           Tidal Station disk                        VM#:    13327
AGENCY:                  National Ocean Service (NOS)              PID:         
SETTING CLASSIFICATION:  Concrete curb


The bench mark is a disk set in top of a concrete curb of the old Dumbarton
Bridge, on the NE side of the road, 274 m (900 ft) NE of the SW end of the
bridge, 6 m (20 ft) west of the seventh wood bench from the shore end of the
pier, 0.30 m (1 ft) SE of NW face of bridge, and 0.25 m (0.8 ft) above road.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  5

                                                   PUBLICATION DATE:  11/08/2000
Station ID: 9414509                                SUPERCEDED DATE:   04/21/2003
Name:       DUMBARTON BRIDGE, SAN FRANCISCO BAY               
            CALIFORNIA
NOAA Chart: 18651                                  Latitude:         37° 30.4' N
USGS Quad:  NEWARK                                 Longitude:       122°  6.9' W


                            T I D A L   D A T U M S 


Tidal datums at DUMBARTON BRIDGE, SAN FRANCISCO BAY based on:

     LENGTH OF SERIES:      16 MONTHS
     TIME PERIOD:           April 1996 - July 1997
     TIDAL EPOCH:           1960-1978
     CONTROL TIDE STATION:  9414750 ALAMEDA, SAN FRANCISCO BAY


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

     HIGHEST OBSERVED WATER LEVEL (12/10/1996)         =  3.115
     MEAN HIGHER HIGH WATER                     MHHW   =  2.550
     MEAN HIGH WATER                            MHW    =  2.364
     MEAN SEA LEVEL                             MSL    =  1.377
     MEAN TIDE LEVEL                            MTL    =  1.362
     MEAN LOW WATER                             MLW    =  0.361
     MEAN LOWER LOW WATER                       MLLW   =  0.000
     LOWEST  OBSERVED WATER LEVEL (12/02/1975)         = -0.653

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     U 553 1956                                  7.307    4.943
     V 553 1956                                  7.190    4.826
     4509 G 1983                                 3.073    0.709
     4509 H 1983                                 3.346    0.982
     4509 K 1996                                 7.135    4.771


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

                                                   PUBLICATION DATE:  11/08/2000
Station ID: 9414509                                SUPERCEDED DATE:   04/21/2003
Name:       DUMBARTON BRIDGE, SAN FRANCISCO BAY               
            CALIFORNIA
NOAA Chart: 18651                                  Latitude:         37° 30.4' N
USGS Quad:  NEWARK                                 Longitude:       122°  6.9' 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.

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