U.S. DEPARTMENT OF COMMERCE
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National Ocean Service
Datums Page Page 1 of 6
Station ID: 9414873 PUBLICATION DATE: 06/23/2003
Name: POINT SAN QUENTIN, SAN FRANCISCO BAY
CA
NOAA Chart: 18649 Latitude: 37° 56.7' N ( 37.94500)
USGS Quad: SAN QUENTIN Longitude: 122° 28.5' W (-122.47500)
To reach the tidal bench marks from San Rafael, proceed east on Interstate Route
580 towards the Richmond-San Rafael Bridge and exit at the last ramp before the
bridge, then turn left and proceed NE on Main Street, under the highway to the
end of the road, then turn left and proceed west on Francisco Boulevard East,
then bear right along the driveway into the Marin Rod and Gun Club. The bench
marks are located on the Marin Rod and Gun Club property and across the highway
from the Gun Club along the road leading to the San Quentin prison. The tide
gage and staff were located on the Marin Rod and Gun Fishing 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: 9414873 PUBLICATION DATE: 06/23/2003
Name: POINT SAN QUENTIN, SAN FRANCISCO BAY
CA
NOAA Chart: 18649 Latitude: 37° 56.7' N ( 37.94500)
USGS Quad: SAN QUENTIN Longitude: 122° 28.5' W (-122.47500)
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: N 551 1956
DESIGNATION: N 551
MONUMENTATION: Bench Mark disk VM#: 8473
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: HT1045
SETTING CLASSIFICATION: Concrete foundation OPUS PID:
LATITUDE: 37° 56.6' N ( 37.94330) LONGITUDE: 122° 28.8' W (-122.48000)
The primary bench mark is a disk set in top of the concrete foundation for the
western flagpole, midway between the NW corner of the flagpole and NW corner of
the foundation, at the Richmond-San Rafael toll bridge maintenance building,
3.44 m (11.3 ft) SE of a fence, 2.93 m (9.6 ft) north of the NW corner of the
building, 1.28 m (4.2 ft) east of the centerline Main Street, and 0.91 m (3.0
ft) above the street.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 6
Station ID: 9414873 PUBLICATION DATE: 06/23/2003
Name: POINT SAN QUENTIN, SAN FRANCISCO BAY
CA
NOAA Chart: 18649 Latitude: 37° 56.7' N ( 37.94500)
USGS Quad: SAN QUENTIN Longitude: 122° 28.5' W (-122.47500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 6 1936
DESIGNATION: TIDAL 6 STA III 81
MONUMENTATION: Bench Mark disk VM#: 8469
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: HT1047
SETTING CLASSIFICATION: Concrete foundation OPUS PID:
LATITUDE: 37° 56.5' N ( 37.94170) LONGITUDE: 122° 29.1' W (-122.48500)
The bench mark is a disk set in the top of the SE corner of the concrete
foundation for two massive concrete posts, at the concrete apron at the south
entrance to the San Quentin post office building, and 2.50 m (8.2 ft) south of
the SE corner.
BENCH MARK STAMPING: NO 13 1949
DESIGNATION: 941 4873 13 1949
MONUMENTATION: Tidal Station disk VM#: 8470
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: HT1046
SETTING CLASSIFICATION: Concrete junction box OPUS PID:
LATITUDE: 37° 56.6' N ( 37.94330) LONGITUDE: 122° 28.8' W (-122.48000)
The bench mark is a disk set in the SW corner of a 3 m x 4 m (11 ft x 14 ft)
concrete junction box for a cable crossing of the Pacific Telephone and
Telegraph Company on the east side of the highway leading to San Quentin prison,
15 m (48 ft) east of the centerline of the Main Street, 9.08 m (29.8 ft) south
of the south fence of San Rafael maintenance yard, 8.08 m (26.5 ft) west of the
top of the concrete rock retaining wall at the store, and level with the street.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 6
Station ID: 9414873 PUBLICATION DATE: 06/23/2003
Name: POINT SAN QUENTIN, SAN FRANCISCO BAY
CA
NOAA Chart: 18649 Latitude: 37° 56.7' N ( 37.94500)
USGS Quad: SAN QUENTIN Longitude: 122° 28.5' W (-122.47500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 4873 F 1977
DESIGNATION: 941 4873 F
MONUMENTATION: Tidal Station disk VM#: 8471
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID:
LATITUDE: 37° 56.7' N ( 37.94500) LONGITUDE: 122° 28.4' W (-122.47300)
The bench mark is a disk located in the parking lot of the Marin Rod and Gun
Club, 46 m (150 ft) NW of the north edge of Highway 17, 25.30 m (83.0 ft) SE of
the Marin Rod and Gun Club sign at the entrance to the club property, 20 m (64
ft) east of the electric gate opener, and 0.55 m (1.8 ft) east of an electric
pole. The bench mark is crimped to the top of a copper-clad steel rod driven
8.8 m (29 ft) to substantial resistance and encased in a PVC pipe extending 0.12
m (0.4 ft) above grade.
BENCH MARK STAMPING: 4873 G 1677
DESIGNATION: 941 4873 G
MONUMENTATION: Tidal Station disk VM#: 8472
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID:
LATITUDE: 37° 56.7' N ( 37.94500) LONGITUDE: 122° 28.4' W (-122.47300)
The bench mark is a disk located NE of the intersection of Main Street and
Francisco Boulevard East, 84 m (276 ft) SE from the SE top corner of the Marin
Rod and Gun Club boat launch ramp, 50 m (165 ft) ESE from the NE corner of a
brick wall at the east side of the Gun Club entrance, 14 m (45 ft) NNE from the
square concrete culvert along the north side of the freeway offramp at San
Quentin, 1.52 m (5.0 ft) NNW from a redwood witness post, and 0.91 m (3.0 ft)
above grade. The bench mark is crimped to the top of a copper-clad steel rod
driven to an unspecified depth.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 6
Station ID: 9414873 PUBLICATION DATE: 06/23/2003
Name: POINT SAN QUENTIN, SAN FRANCISCO BAY
CA
NOAA Chart: 18649 Latitude: 37° 56.7' N ( 37.94500)
USGS Quad: SAN QUENTIN Longitude: 122° 28.5' W (-122.47500)
T I D A L D A T U M S
Tidal datums at POINT SAN QUENTIN, SAN FRANCISCO BAY based on:
LENGTH OF SERIES: 3 MONTHS
TIME PERIOD: September 1978 - November 1978
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 9414290 SAN FRANCISCO, SAN FRANCISCO BAY
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 1.762
MEAN HIGH WATER MHW = 1.578
MEAN TIDE LEVEL MTL = 0.951
MEAN SEA LEVEL MSL = 0.937
MEAN LOW WATER MLW = 0.324
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum NAVD88 = -0.051
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
N 551 1956 4.957 3.379
6 1936 10.585 9.007
NO 13 1949 5.910 4.332
4873 F 1977 3.415 1.837
4873 G 1677 2.355 0.777
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 6
Station ID: 9414873 PUBLICATION DATE: 06/23/2003
Name: POINT SAN QUENTIN, SAN FRANCISCO BAY
CA
NOAA Chart: 18649 Latitude: 37° 56.7' N ( 37.94500)
USGS Quad: SAN QUENTIN Longitude: 122° 28.5' W (-122.47500)
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.