U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 4
PUBLICATION DATE: 09/03/1983
Station ID: 9414637 SUPERCEDED DATE: 04/21/2003
Name: SAN MATEO BRIDGE, EAST END, SAN FRANCISCO BAY
CALIFORNIA
NOAA Chart: 18651 Latitude: 37° 36.5' N
USGS Quad: REDWOOD POINT Longitude: 122° 10.9' W
To reach the tidal bench marks from U.S. Highway 101 proceed east on State Route
92 over San Mateo Bridge to bench marks on the east end of the bridge. The tide
gage and staff were located on the south side of bridget at SE corner of
substation No. 7.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 4637 A 1976
MONUMENTATION: Survey Disk VM#: 8377
AGENCY: PID#: HT2346
SETTING CLASSIFICATION: Concrete Ledge
The bench mark is set flush in the concrete ledge on the south side of San
Mateo-Hayward Bridge, at mileage marker 665, 28 feet (8.5 m) SSE of the
centerline of the bridge, 27 feet (8.2 m) ENE of the NE corner of substation No.
5, 0.8 foot (0.2 m) NNW of the concrete guardrail, and 0.4 foot (0.1 m) SSE of
the north end of the concrete ledge.
BENCH MARK STAMPING: 4637 B 1976
MONUMENTATION: Survey Disk VM#: 8378
AGENCY: PID#: HT2345
SETTING CLASSIFICATION: Concrete Ledge
The bench mark is set horizontally in concrete ledge/walkway on the south side
of the San Mateo-Hayward Bridge near mileage marker 695, 770 feet (235 m) ENE of
Bench Mark 4637 A 1976, 28 feet (8.5 m) SSE of the centerline of the bridge, 0.8
foot (0.2 m) NNW of the concrete guardrail, and 0.9 foot (0.3 m) above the
roadway.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 4
PUBLICATION DATE: 09/03/1983
Station ID: 9414637 SUPERCEDED DATE: 04/21/2003
Name: SAN MATEO BRIDGE, EAST END, SAN FRANCISCO BAY
CALIFORNIA
NOAA Chart: 18651 Latitude: 37° 36.5' N
USGS Quad: REDWOOD POINT Longitude: 122° 10.9' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 4637 C 1976
MONUMENTATION: Survey Disk VM#: 8379
AGENCY: PID#: HT2344
SETTING CLASSIFICATION: Concrete Ledge
The bench mark is set horizontally in the concrete ledge/walkway on the south
side of the bridge near mileage marker No. 720, 785 feet (239 m) ENE of Bench
Mark 4637 B 1976, 28 feet (8.5 m) SSE of the centerline of the bridge, 12 feet
(3.7 m) ENE of the San Mateo/Alameda county line sign, 0.8 foot (0.2 m) NNW of
the concrete guardrail, and 0.9 foot (0.3 m) above the roadway.
BENCH MARK STAMPING: 4637 D 1977
MONUMENTATION: Survey Disk VM#: 8380
AGENCY: PID#: HT2343
SETTING CLASSIFICATION: Curb
The bench mark is set in the curb on the southside of the San Mateo-Hayward
Bridge, 450 feet (137 m) NE of Bench Mark 4637 C 1976, 30 feet (9.1 m) NE of
service box No. 92 and 0.5 foot (0.2 m) NE of painted number 735.
BENCH MARK STAMPING: 4637 E 1977
MONUMENTATION: Survey Disk VM#: 8381
AGENCY: PID#: HT2342
SETTING CLASSIFICATION: Curb
The bench mark is set flush in the curb on the south side of the San
Mateo-Hayward Bridge, 472 feet (144 m) NE of Bench Mark 4637 D 1977, 29 feet
(8.8 m) NE of a service box, and 1 foot (0.3 m) NE of the edge of section 753 of
the bridge.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 4
PUBLICATION DATE: 09/03/1983
Station ID: 9414637 SUPERCEDED DATE: 04/21/2003
Name: SAN MATEO BRIDGE, EAST END, SAN FRANCISCO BAY
CALIFORNIA
NOAA Chart: 18651 Latitude: 37° 36.5' N
USGS Quad: REDWOOD POINT Longitude: 122° 10.9' W
T I D A L D A T U M S
Tidal datums at SAN MATEO BRIDGE, EAST END, SAN FRANCISCO BAY based on:
LENGTH OF SERIES: 3 MONTHS
TIME PERIOD: JANUARY-MARCH 1977
TIDAL EPOCH: 1960-1978
CONTROL TIDE STATION: 9414458 SAN MATEO BRIDGE, CA
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET:
HIGHEST OBSERVED WATER LEVEL (12/20/1976) = 9.15
MEAN HIGHER HIGH WATER MHHW = 7.68
MEAN HIGH WATER MHW = 7.07
MEAN TIDE LEVEL MTL = 4.12
MEAN LOW WATER MLW = 1.18
MEAN LOWER LOW WATER MLLW = 0.00
LOWEST OBSERVED WATER LEVEL (12/21/1976) = -1.83
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In FEET above:
Stamping or Designation MLLW MHW
4637 A 1976 18.99 11.92
4637 B 1976 19.00 11.93
4637 C 1976 19.00 11.93
4637 D 1977 18.99 11.92
4637 E 1977 19.01 11.94
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 4
PUBLICATION DATE: 09/03/1983
Station ID: 9414637 SUPERCEDED DATE: 04/21/2003
Name: SAN MATEO BRIDGE, EAST END, SAN FRANCISCO BAY
CALIFORNIA
NOAA Chart: 18651 Latitude: 37° 36.5' N
USGS Quad: REDWOOD POINT Longitude: 122° 10.9' 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.