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Bench Mark Sheet for 9414519, MOWRY SLOUGH, SAN FRANCISCO BAY 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Superseded Epoch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Small blue map location marker Unpublished bench mark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: 9414519                         PUBLICATION DATE:  02/07/2005
Name:       MOWRY SLOUGH, SAN FRANCISCO BAY                   
            CA
NOAA Chart: 18651                           Latitude:   37° 29.6' N (  37.49330)
USGS Quad:  MOUNTAINVIEW                    Longitude: 122°  2.5' W (-122.04200)


To reach the tidal bench marks from the State Highway 17 exit at Thornton Avenue
West, go SW for two blocks to Cedar Boulevard, then turn left and go two blocks
on Cedar Boulevard to Central Avenue, then turn right and proceed on Central
Avenue to Leslie Salt Co., then turn left into the main gate of Leslie Salt Co.
and proceed for 0.18 km (0.11 mi) to a chainlink fence, then turn right and
continue 0.64 km (0.40 mi) to a T-junction, then turn left and proceed 0.18 km
(0.11 mi) to a Y-junction, then turn right and proceed 0.64 km (0.40 mi) to a
T-junction, then turn right and proceed 1.05 km (0.65 mi) to a wooden building,
then turn right at the Y-junction after the wooden building and proceed 9 m (30
ft) to a Y-junction, then turn left and proceed 1.69 km (1.05 mi) to a
T-junction.  The tide gage and staff were located on a freestanding piling in
the slough, and the bench marks are along the Salt Levee Road.


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


                 PRIMARY BENCH MARK STAMPING:  4519 A 1976
                         DESIGNATION:          941 4519 A TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         8314
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  HT2392
SETTING CLASSIFICATION:  Unspecified deep rod                  OPUS PID#: HT2392
LATITUDE:   37° 29.6' N (  37.49330)          LONGITUDE: 122°  2.5' W (-122.04200)


The primary bench mark is a disk, 134 m (440 ft) WSW of bench mark 4519 B 1976,
107 m (350 ft) north of the north bank of the slough, 4 m (13 ft) SSE of the
centerline of Leslie Salt Company levee road parallel to the slough and 0.76 m
(2.5 ft) east of a witness post.  The bench mark is crimped to the top of an
unspecified deep rod driven 14.6 m (48 ft) to substantial resistance, and
encased in a PVC pipe that extends 15 cm (0.5 ft) above grade.

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

                                                                                
Station ID: 9414519                         PUBLICATION DATE:  02/07/2005
Name:       MOWRY SLOUGH, SAN FRANCISCO BAY                   
            CA
NOAA Chart: 18651                           Latitude:   37° 29.6' N (  37.49330)
USGS Quad:  MOUNTAINVIEW                    Longitude: 122°  2.5' W (-122.04200)


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


                         BENCH MARK STAMPING:  4519 B 1976
                         DESIGNATION:          941 4519 B TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         8315
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  HT2394
SETTING CLASSIFICATION:  Unspecified deep rod                  OPUS PID:        
LATITUDE:   37° 29.6' N (  37.49330)          LONGITUDE: 122°  2.5' W (-122.04200)


The bench mark is a disk, 152 m (500 ft) north of north bank of the slough, 155
m (445 ft) west of bench mark 4519 C 1976, 134 m (440 ft) ENE of bench mark 4519
A 1976, 21 m (68 ft) SSE of bench mark STA 16 1975 L8 3936, 7 m (22 ft) south of
the centerline of the levee road, 0.76 m (2.5 ft) ESE of a witness post, and on
south side of Leslie Salt Company levee road parallel to the slough.  The bench
mark is crimped to the top of an unspecified deep rod driven 17.1 m (56 ft) to
substantial resistance, and encased in a PVC pipe that extends 18 cm (0.6 ft)
above grade.



                         BENCH MARK STAMPING:  4519 C 1976
                         DESIGNATION:          941 4519 C TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         8316
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  HT2395
SETTING CLASSIFICATION:  Unspecified deep rod                  OPUS PID:        
LATITUDE:   37° 29.6' N (  37.49330)          LONGITUDE: 122°  2.5' W (-122.04200)


The bench mark is a disk, 152 m (500 ft) north of north bank of the slough, 152
m (500 ft) NNW of beached house boat on the north bank of the slough, 137 m (450
ft) WNW of bench mark 4519 D 1976, 5 m (16 ft) south of the centerline of Leslie
Salt Company levee road parallel to the slough, and 1 m (2 ft) WNW of a witness
post.  The bench mark is set 1 m (3 ft) below road level, crimped to the top of
an unspecified deep rod driven 19.5 m (64 ft) to substantial resistance, and
encased in a PVC pipe that extends 12 cm (0.4 ft) above the grade.

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

                                                                                
Station ID: 9414519                         PUBLICATION DATE:  02/07/2005
Name:       MOWRY SLOUGH, SAN FRANCISCO BAY                   
            CA
NOAA Chart: 18651                           Latitude:   37° 29.6' N (  37.49330)
USGS Quad:  MOUNTAINVIEW                    Longitude: 122°  2.5' W (-122.04200)


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


                         BENCH MARK STAMPING:  4519 D 1976
                         DESIGNATION:          941 4519 D TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         8317
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  HT2396
SETTING CLASSIFICATION:  Unspecified deep rod                  OPUS PID:        
LATITUDE:   37° 29.6' N (  37.49330)          LONGITUDE: 122°  2.5' W (-122.04200)


The bench mark is a disk, 140 m (459 ft) west of bench mark 4519 E 1976, 137 m
(450 ft) ESE of bench mark 4519 C 1976, 137 m (450 ft) north of north bank of
the slough, 5 m (17 ft) south of the centerline of Leslie Salt Company levee
road parallel to the slough, and 1 m (3 ft) NW of a witness post. The bench mark
is set 1 m (3 ft) below the road level, crimped to the top of an unspecified
deep rod driven 19.8 m (65 ft) to substantial resistance, and encased in a PVC
pipe that extends 15 cm (0.5 ft) above the grade.



                         BENCH MARK STAMPING:  4519 E 1976
                         DESIGNATION:          941 4519 E TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         8318
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  HT2397
SETTING CLASSIFICATION:  Unspecified deep rod                  OPUS PID:        
LATITUDE:   37° 29.6' N (  37.49330)          LONGITUDE: 122°  2.5' W (-122.04200)


The bench mark is a disk located 1.1 km (0.7 mi) west of the junction of the
road leading to the duck club, 168 m (550 ft) north of the north bank of the
slough, 140 m (459 ft) east of bench mark 4519 D 1976, 2 m (8 ft) SSE of the
centerline of Leslie Salt Company levee and parallel to the slough, and 2 m (5
ft) north of a witness post.  The bench mark is crimped to the top of an
unspecified deep rod driven 15.2 m (50 ft) to substantial resistance, and
protected by a PVC pipe.

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

                                                                                
Station ID: 9414519                         PUBLICATION DATE:  02/07/2005
Name:       MOWRY SLOUGH, SAN FRANCISCO BAY                   
            CA
NOAA Chart: 18651                           Latitude:   37° 29.6' N (  37.49330)
USGS Quad:  MOUNTAINVIEW                    Longitude: 122°  2.5' W (-122.04200)


                            T I D A L   D A T U M S 


Tidal datums at MOWRY SLOUGH, SAN FRANCISCO BAY based on:

     LENGTH OF SERIES:      1 MONTH
     TIME PERIOD:           December 1984 - December 1984
     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   =  2.633
     MEAN HIGH WATER                            MHW    =  2.444
     MEAN SEA LEVEL                             MSL    =  1.420
     MEAN TIDE LEVEL                            MTL    =  1.397
     MEAN LOW WATER                             MLW    =  0.351
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     4519 A 1976                                 3.273    0.829
     4519 B 1976                                 3.295    0.851
     4519 C 1976                                 3.196    0.752
     4519 D 1976                                 3.384    0.940
     4519 E 1976                                 3.569    1.125


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

                                                                                
Station ID: 9414519                         PUBLICATION DATE:  02/07/2005
Name:       MOWRY SLOUGH, SAN FRANCISCO BAY                   
            CA
NOAA Chart: 18651                           Latitude:   37° 29.6' N (  37.49330)
USGS Quad:  MOUNTAINVIEW                    Longitude: 122°  2.5' W (-122.04200)


                             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 9414519 MOWRY SLOUGH, SAN FRANCISCO BAY, CA

Revised: 10/15/2013
NOAA / National Ocean Service
Web site owner: Center for Operational Oceanographic Products and Services