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Bench Mark Sheet for 9414688, San Leandro Marina CA

Superseded Epoch

Large map location marker Station Location
Small red map location marker Published bench mark
Small blue map location marker Unpublished bench mark

Bench mark positions only appear on the map if their coordinates in the CO-OPS database are at the precision of degrees/minutes/seconds/and tenths of seconds. If the coordinates are less precise, the mark will not appear.

Printable version

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

                                                                                
Station ID: 9414688                         PUBLICATION DATE:  08/03/2004
Name:       SAN LEANDRO MARINA, SAN FRANCISCO BAY             
            CA
NOAA Chart: 18651                           Latitude:   37° 41.7' N (  37.69500)
USGS Quad:  SAN LEANDRO                     Longitude: 122° 11.5' W (-122.19200)


To reach the tidal bench marks from San Leandro, proceed SW on Marina Boulevard
or Fairway Drive to Neptune Drive in San Leandro, then turn on Neptune Drive
towards North Dike Road (between Marina Boulevard and Fairway Drive), then turn
and proceed west on North Dike Road to the Blue Dolphin Restaurant, then south
to Mulford Point on the north side of the entrance to the San Leandro Channel
Harbor.  The bench marks are located around the boat docking facilities.  The
tide gage and staff were located on channel marker piling 23.


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


                 PRIMARY BENCH MARK STAMPING:  TIDAL BM 4 1974
                         DESIGNATION:          941 4688 TIDAL 4

MONUMENTATION:           Tidal Station disk                    VM#:         8382
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  HT2331
SETTING CLASSIFICATION:  Concrete curved wall                  OPUS PID:        
LATITUDE:   37° 41.7' N (  37.69500)          LONGITUDE: 122° 11.6' W (-122.19300)


The primary bench mark is a disk set vertically in the south face of a curved
concrete wall that bears a mosaic tile mural on its north face located at the
south end of the westernmost parking lot of San Leandro Marina, 6 m (19 ft)
south of the south end of the parking lot, 0.37 m (1.2 ft) east of the west end
of the wall, and 1.10 m (3.6 ft) above the ground.

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

                                                                                
Station ID: 9414688                         PUBLICATION DATE:  08/03/2004
Name:       SAN LEANDRO MARINA, SAN FRANCISCO BAY             
            CA
NOAA Chart: 18651                           Latitude:   37° 41.7' N (  37.69500)
USGS Quad:  SAN LEANDRO                     Longitude: 122° 11.5' W (-122.19200)


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


                         BENCH MARK STAMPING:  TIDAL BM 6 1974
                         DESIGNATION:          941 4688 TIDAL 6

MONUMENTATION:           Tidal Station disk                    VM#:         8384
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  HT2329
SETTING CLASSIFICATION:  Concrete foundation                   OPUS PID:        
LATITUDE:   37° 41.9' N (  37.69830)          LONGITUDE: 122° 11.6' W (-122.19300)


The bench mark is a disk set flush in the top of the concrete foundation that
supports the inshore end of the northernmost pier leading to Float A, 18 m (60
ft) south of the SW post supporting the roof over the main (west) entrance to
the Blue Dolphin Restaurant, 7.10 m (23.3 ft) east of the east curb of the
parking lot, 0.12 m (0.4 ft) south of the north edge of the foundation, and 0.43
m (1.4 ft) below the top of the pier.



                         BENCH MARK STAMPING:  4688 B 1976
                         DESIGNATION:          941 4688 B TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         8386
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  HT2327
SETTING CLASSIFICATION:  Copper clad steel rod                 OPUS PID#: HT2327
LATITUDE:   37° 42.1' N (  37.70170)          LONGITUDE: 122° 11.4' W (-122.19000)


The bench mark is a disk located at the entrance to the San Leandro Marina on
Marina Boulevard, 43 m (142 ft) SW of the centerline of the intersection of
Marina Boulevard and the west shoreline road, 16 m (51 ft) NW of the centerline
of Marina Boulevard, 15 m (50 ft) NNE of a pumping station building, 6.86 m
(22.5 ft) SE of the west shoreline within the marine grounds, and 0.91 m (3.0
ft) NNW from the NNW vertical pipe making up a metal sculpture (shape of a
sailboat).  The mark is crimped to the top of a copper-clad steel rod driven
21.5 m (70.5 ft) to substantial refusal.

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

                                                                                
Station ID: 9414688                         PUBLICATION DATE:  08/03/2004
Name:       SAN LEANDRO MARINA, SAN FRANCISCO BAY             
            CA
NOAA Chart: 18651                           Latitude:   37° 41.7' N (  37.69500)
USGS Quad:  SAN LEANDRO                     Longitude: 122° 11.5' W (-122.19200)


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


                         BENCH MARK STAMPING:  PARCOURSE NW 1982
                         DESIGNATION:          PARCOURSE NW

MONUMENTATION:           Survey disk                           VM#:         8387
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  HT3757
SETTING CLASSIFICATION:  Irregular mass of concrete            OPUS PID:        
LATITUDE:   37° 41.6' N (  37.69330)          LONGITUDE: 122° 11.5' W (-122.19200)


The bench mark is a disk set in a 15-inch diameter concrete monument, 36 m (118
ft) west of a metal framed wooden bench,  34 m (110 ft) from the nearest edge of
the Par Course Vault Bar No. 10 sign, 33 m (108 ft) west of the west compass
range marker, and 0.15 m (0.5 ft) below the monument surface.

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

                                                                                
Station ID: 9414688                         PUBLICATION DATE:  08/03/2004
Name:       SAN LEANDRO MARINA, SAN FRANCISCO BAY             
            CA
NOAA Chart: 18651                           Latitude:   37° 41.7' N (  37.69500)
USGS Quad:  SAN LEANDRO                     Longitude: 122° 11.5' W (-122.19200)


                            T I D A L   D A T U M S 


Tidal datums at SAN LEANDRO MARINA, SAN FRANCISCO BAY based on:

     LENGTH OF SERIES:      8 MONTHS
     TIME PERIOD:           May 1975 - December 1975
     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   =  2.264
     MEAN HIGH WATER                            MHW    =  2.069
     MEAN TIDE LEVEL                            MTL    =  1.212
     MEAN SEA LEVEL                             MSL    =  1.194
     MEAN LOW WATER                             MLW    =  0.355
     North American Vertical Datum              NAVD88 =  0.187
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     TIDAL BM 4 1974                             5.345    3.276
     TIDAL BM 6 1974                             2.549    0.480
     4688 B 1976                                 2.809    0.740
     PARCOURSE NW 1982                           4.970    2.901


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

                                                                                
Station ID: 9414688                         PUBLICATION DATE:  08/03/2004
Name:       SAN LEANDRO MARINA, SAN FRANCISCO BAY             
            CA
NOAA Chart: 18651                           Latitude:   37° 41.7' N (  37.69500)
USGS Quad:  SAN LEANDRO                     Longitude: 122° 11.5' W (-122.19200)


                             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.

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Products available at 9414688 San Leandro Marina, CA

Revised: 08/08/2018
NOAA / National Ocean Service
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