U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
PUBLICATION DATE: 09/19/1983
Station ID: 9414688 SUPERCEDED DATE: 04/21/2003
Name: SAN LEANDRO MARINA, SAN FRANCISCO BAY
CALIFORNIA
NOAA Chart: 18651 Latitude: 37° 41.7' N
USGS Quad: SAN LEANDRO Longitude: 122° 11.5' W
To reach the tidal bench marks proceed to the San Leandro Marina by way of
Marina Boulevard or Fairway Drive to Neptune Drive in San Leandro, east along
North Dike Road (off Neptune Drive North) to the Blue Dolphin Restaurant and
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
MONUMENTATION: Survey Disk VM#: 8382
AGENCY: PID#: HT2331
SETTING CLASSIFICATION: Concrete Wall
The bench mark is set vertically in the south face of a curved concrete wall
that bears a mosaic tile mural on its north face, at the south end of the
westernmost parking lot of San Leandro Marina, 19 feet (5.8 m) south of the
south end of the parking lot, 1.2 feet (0.4 m) east of the west end of the wall,
and 3.6 feet (1.1 m) above the ground.
BENCH MARK STAMPING: TIDAL BM 5 1974
MONUMENTATION: Survey Disk VM#: 8383
AGENCY: PID#: HT2330
SETTING CLASSIFICATION: Concrete Slab
The bench mark is set flush in the top of a concrete slab foundation of the
restroom building in the west parking lot of San Leandro Marina, 250 feet (76.2
m) north of the pier leading to the harbormasters office, 25 feet (7.6 m) west
of the west bank of the marina, 9.2 feet (2.8 m) west of the east wall of the
building, and 3.5 feet (1.1 m) south of the south wooden wall of the building.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
PUBLICATION DATE: 09/19/1983
Station ID: 9414688 SUPERCEDED DATE: 04/21/2003
Name: SAN LEANDRO MARINA, SAN FRANCISCO BAY
CALIFORNIA
NOAA Chart: 18651 Latitude: 37° 41.7' N
USGS Quad: SAN LEANDRO Longitude: 122° 11.5' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: TIDAL BM 6 1974
MONUMENTATION: Survey Disk VM#: 8384
AGENCY: PID#: HT2329
SETTING CLASSIFICATION: Concrete Foundation
The bench mark is set flush in the top of the concrete foundation that supports
the inshore end of the northernmost pier leading to Float A, 60.0 feet (18.3 m)
south of the SW post supporting the roof over the main (west) entrance to the
Blue Dolphin Restaurant, 23.3 feet (7.1 m) east of the east curb of the parking
lot, 0.4 foot (0.1 m) south of the north edge of the foundation, and 1.4 feet
(0.4 m) below the top of the pier.
BENCH MARK STAMPING: 4688 A 1976
MONUMENTATION: Survey Disk VM#: 8385
AGENCY: PID#: HT2328
SETTING CLASSIFICATION: Concrete
The bench mark is set flush in concrete on the NW corner of the restroom
building between the Dolphin Restasurant and the Tia Maria Restuarant, 0.1 mile
(0.2 km) west of the intersection of North Dike Road and Neptune Street, 400
feet (122 m) west of the San Leandro Yacht Club building, 400 feet (122 m) south
of the boat ramp, 55 feet (16.8 m) NE of the entrance to Pier D at the marina,
and 31 feet (9.4 m) south of the centerline of North Dike Road.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
PUBLICATION DATE: 09/19/1983
Station ID: 9414688 SUPERCEDED DATE: 04/21/2003
Name: SAN LEANDRO MARINA, SAN FRANCISCO BAY
CALIFORNIA
NOAA Chart: 18651 Latitude: 37° 41.7' N
USGS Quad: SAN LEANDRO Longitude: 122° 11.5' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 4688 B 1976
MONUMENTATION: Survey Disk VM#: 8386
AGENCY: PID#: HT2327
SETTING CLASSIFICATION: Rod
The bench mark is located at the entrance to the San Leandro Marina on Marina
Boulevard, 142 feet (43.3 m) SW of the centerline of the intersection of Marina
Boulevard and the west shoreline road, 51 feet (15.5 m) NW of the centerline of
Marina Boulevard, 50 feet (15.2 m) NNW of a pumping station building, 22.5 feet
(6.9 m) SE of the west shoreline within the marine grounds, 3.0 feet (0.9 m) NNW
from the NNW vertical pipe making up a metal sculphure (shape of a sailboat),
and flush with the ground.
BENCH MARK STAMPING: PARCOURSE 1982
MONUMENTATION: Survey Disk VM#: 8387
AGENCY: PID#: HT3757
SETTING CLASSIFICATION: Unknown
The bench mark is on top of a spit of land, south of the entrance to San Leandro
Marina, that encloses a lagoon in a community park, 120 feet (36.6 m) west of a
vault bar 0.3 foot (0.1 m) below the ground, 108 feet (33 m) from the west
banner of a compass range, and 10 feet (3.0 m) south of the upper edge of the
riprap bank.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
PUBLICATION DATE: 09/19/1983
Station ID: 9414688 SUPERCEDED DATE: 04/21/2003
Name: SAN LEANDRO MARINA, SAN FRANCISCO BAY
CALIFORNIA
NOAA Chart: 18651 Latitude: 37° 41.7' N
USGS Quad: SAN LEANDRO Longitude: 122° 11.5' W
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: 19 MONTHS
TIME PERIOD: NOVEMBER 1974 - AUGUST 1976
TIDAL EPOCH: 1960-1978
CONTROL TIDE STATION: 9424750 ALAMEDA, CA
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET:
HIGHEST OBSERVED WATER LEVEL (12/27/1974) = 8.62
MEAN HIGHER HIGH WATER MHHW = 7.31
MEAN HIGH WATER MHW = 6.69
MEAN TIDE LEVEL MTL = 3.92
MEAN LOW WATER MLW = 1.14
MEAN LOWER LOW WATER MLLW = 0.00
LOWEST OBSERVED WATER LEVEL (04/17/1976) = -2.00
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In FEET above:
Stamping or Designation MLLW MHW
TIDAL BM 4 1974 17.60 10.91
TIDAL BM 5 1974 12.51 5.82
TIDAL BM 6 1974 8.41 1.72
4688 A 1976 12.35 5.66
4688 B 1976 9.27 2.58
PARCOURSE 1982 16.37 9.68
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
PUBLICATION DATE: 09/19/1983
Station ID: 9414688 SUPERCEDED DATE: 04/21/2003
Name: SAN LEANDRO MARINA, SAN FRANCISCO BAY
CALIFORNIA
NOAA Chart: 18651 Latitude: 37° 41.7' N
USGS Quad: SAN LEANDRO Longitude: 122° 11.5' 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.