U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 10
Station ID: 9414750 PUBLICATION DATE: 10/07/2011
Name: ALAMEDA, SAN FRANCISCO BAY
CA
NOAA Chart: 18649 Latitude: 37° 46.3' N ( 37.77167)
USGS Quad: OAKLAND WEST Longitude: 122° 17.9' W (-122.29833)
To reach the tidal bench marks, take Highway I-880 to Broadway exit, watch for
Freeway 61 to Alameda and go west on Freeway 61 through the Alameda Tube, take
the second right on Atlantic Road after the Tube. Atlantic dead ends into
Alameda Naval Air Station main gate, go straight through the main gate and turn
left onto Ferry Point Road and proceed along waterfront to Pier 3. The bench
marks were located in the vicinity of Piers 1, 2, and 3. The tide house is
located on the east end of Pier 3.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: NO 8 1939
DESIGNATION: 941 4750 TIDAL 8
MONUMENTATION: Tidal Station disk VM#: 983
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: HT0890
SETTING CLASSIFICATION: Concrete curb OPUS PID:
LATITUDE: 37° 46.5' N ( 37.77528) LONGITUDE: 122° 18.0' W (-122.29944)
The primary bench mark is a disk set in the top of the north concrete curb
located at the east end of Tender Pier Number 1, at the junction of Ferry Point
Road, 8.08 m (26.5 ft) SW of the SW corner of a corrugated metal building
(formerly No. 601), 4.72 m (15.5 ft) offshore from the steel bulkhead, 1.07 m
(3.5 ft) south of the north face of the pier, at the SE corner of the lagoon,
and 0.30 m (1.0 ft) above the deck.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 10
Station ID: 9414750 PUBLICATION DATE: 10/07/2011
Name: ALAMEDA, SAN FRANCISCO BAY
CA
NOAA Chart: 18649 Latitude: 37° 46.3' N ( 37.77167)
USGS Quad: OAKLAND WEST Longitude: 122° 17.9' W (-122.29833)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 7 1939
DESIGNATION: 941 4750 TIDAL 7
MONUMENTATION: Tidal Station disk VM#: 984
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: HT0882
SETTING CLASSIFICATION: Concrete sea wall OPUS PID#: HT0882
LATITUDE: 37° 46.8' N ( 37.78000) LONGITUDE: 122° 17.9' W (-122.29819)
The bench mark is a disk set in the top of a concrete bulkhead located at the NE
corner of the lagoon, 36.88 m (121.0 ft) west of the west corner of Building No.
66, 17.98 m (59.0 ft) west of the centerline of Ferry Point Road, 6.71 m (22.0
ft) north of the extended centerline of Atlantic Avenue, 3.96 m (13.0 ft) west
of the end of the sea wall, 0.76 m (2.5 ft) north of its south side, and at the
SE corner of the concrete airplane landing field.
BENCH MARK STAMPING: NO 11 1972
DESIGNATION: 941 4750 TIDAL 11
MONUMENTATION: Tidal Station disk VM#: 985
AGENCY: National Ocean Survey (NOS) IDB PID#: HT3550
SETTING CLASSIFICATION: Concrete pavement OPUS PID:
LATITUDE: 37° 46.5' N ( 37.77417) LONGITUDE: 122° 18.0' W (-122.30056)
The bench mark is a disk set in concrete pavement located near the eastern end
of Pier No. 2, 41.80 m (137.1 ft) NE of the north corner of a concrete building
at the end of Pier 2, 12.59 m (41.3 ft) east of the centerline of Ferry Point
Road, 9.25 m (30.3 ft) south of lightpole # 7400, and 0.61 m (2.0 ft) from the
SW corner of a corrugated metal building (formerly No. 340).
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 10
Station ID: 9414750 PUBLICATION DATE: 10/07/2011
Name: ALAMEDA, SAN FRANCISCO BAY
CA
NOAA Chart: 18649 Latitude: 37° 46.3' N ( 37.77167)
USGS Quad: OAKLAND WEST Longitude: 122° 17.9' W (-122.29833)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 12 1972
DESIGNATION: 941 4750 TIDAL 12
MONUMENTATION: Tidal Station disk VM#: 986
AGENCY: National Ocean Survey (NOS) IDB PID#: HT3551
SETTING CLASSIFICATION: Concrete pier OPUS PID:
LATITUDE: 37° 46.3' N ( 37.77194) LONGITUDE: 122° 17.9' W (-122.29861)
The bench mark is a disk set at ground level in the concrete pier located near
the eastern end of Pier No. 3, 7.32 m (24.0 ft) north of the southern edge of
Pier No. 3, 0.4 m (1.5 ft) west of the eastern edge of Pier No. 3, and 0.30 m
(1.0 ft) north of the northern face of the tide station.
BENCH MARK STAMPING: 4750 P 1976
DESIGNATION: 941 4750 P
MONUMENTATION: Tidal Station disk VM#: 987
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID:
LATITUDE: 37° 46.3' N ( 37.77200) LONGITUDE: 122° 18.0' W (-122.29933)
The bench mark is a disk set on a rod located 41.2 m (135.4 ft) west of the west
edge of a large steel ships bollard in the barbeque area, 27.0 m (88.6 ft) south
of the centerline of W Hornet Ave, 4.27 m (14.0 ft) north of the south edge of a
concrete walkway parallel to the shoreline, and 0.21 m (0.7 ft) east of the road
where the road begins to intersect a sidewalk. The bench mark is crimped to a
copper-clad steel rod driven 17.10 m (56.1 ft) to refusal, and encased in a
4-inch PVC pipe with screw cap.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 10
Station ID: 9414750 PUBLICATION DATE: 10/07/2011
Name: ALAMEDA, SAN FRANCISCO BAY
CA
NOAA Chart: 18649 Latitude: 37° 46.3' N ( 37.77167)
USGS Quad: OAKLAND WEST Longitude: 122° 17.9' W (-122.29833)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 4750 Q 1976
DESIGNATION: 941 4750 Q TIDAL
MONUMENTATION: Tidal Station disk VM#: 988
AGENCY: National Ocean Survey (NOS) IDB PID#: HT3554
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID:
LATITUDE: 37° 47.0' N ( 37.78361) LONGITUDE: 122° 17.8' W (-122.29722)
The bench mark is a disk set on a rod located 9.45 m (31.0 ft) west of the NW
corner of a concrete foundation supporting a pumping station, 3.00 m (9.8 ft)
south of the south edge of the sidewalk, and 0.61 m (2.0 ft) south of a witness
post with sign. The bench mark is set flush with the ground, crimped to the top
of a copper-clad steel rod driven 15.51 m (50.9 ft), and encased in a 4-inch PVC
pipe.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 10
Station ID: 9414750 PUBLICATION DATE: 10/07/2011
Name: ALAMEDA, SAN FRANCISCO BAY
CA
NOAA Chart: 18649 Latitude: 37° 46.3' N ( 37.77167)
USGS Quad: OAKLAND WEST Longitude: 122° 17.9' W (-122.29833)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING:
DESIGNATION: LAGOON
ALIAS: USN Lagoon Center
MONUMENTATION: Metal Rod VM#: 992
AGENCY: US Army Corps of Engineers (USE) IDB PID#: HT0888
SETTING CLASSIFICATION: Sea wall OPUS PID:
LATITUDE: 37° 46.7' N ( 37.77833) LONGITUDE: 122° 17.9' W (-122.29806)
The bench mark is a 1-inch brass plug, unstamped, set in the cap rock of the
seawall located on the east side of the lagoon, 155.45 m (510.0 ft) south of the
junction of Ferry Point Road and Atlantic Avenue, 34.44 m (113.0 ft) south of
the north end of the point where a 9-inch steel pipeline along Ferry Point Road
goes underground, 1.16 m (3.8 ft) west of the west curb of Ferry Point Road, and
0.15 m (0.5 ft) east of the center of 9-inch steel pipe, and directly beneath a
witness sign banded to the 9-inch steel pipe.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 10
Station ID: 9414750 PUBLICATION DATE: 10/07/2011
Name: ALAMEDA, SAN FRANCISCO BAY
CA
NOAA Chart: 18649 Latitude: 37° 46.3' N ( 37.77167)
USGS Quad: OAKLAND WEST Longitude: 122° 17.9' W (-122.29833)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING:
DESIGNATION: WATER TANK NORTH
ALIAS: USN Water Tank North
MONUMENTATION: Bolt VM#: 993
AGENCY: US Army Corps of Engineers (USE) IDB PID#: HT0884
SETTING CLASSIFICATION: Concrete foundation OPUS PID:
LATITUDE: 37° 47.1' N ( 37.78444) LONGITUDE: 122° 17.8' W (-122.29722)
The bench mark is a 1 inch brass plug , unstamped, set in a drill hole in top of
the west concrete foundation (western one of six) of the northern-most one of
two steel water tanks at Alameda Naval Air Station, 44.50 m (146.0 ft) east of
the east curb of Ferry Point Road, nearly on the extended south curb line of
Avenue D, 2.96 m (9.7 ft) north of a 1 m (3 ft) tall riser and valve of a
concrete vault, 0.2 m (0.5 ft) east of the west side of the footing, and 0.5 m
(1.5 ft) above the ground.
BENCH MARK STAMPING: 4750 S 1993
DESIGNATION: 941 4750 S
MONUMENTATION: Tidal Station disk VM#: 11067
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete vault OPUS PID:
LATITUDE: 37° 46.3' N ( 37.77172) LONGITUDE: 122° 17.9' W (-122.29814)
TThe bench mark is a disk cemented into a 2.40 m x 5.50 m (7.9 ft x 18.0 ft)
concrete vault, 15.3 m (50.2 ft) west of utility box # 592, 6.51 m (21.4 ft) NNW
of the NW end of the concrete bulkhead running east-west along the bay, 5.7 m
(18.7 ft) NNE of information sign "An Era of Dramatic Change", 0.21 m (0.7 ft)
south of the north edge of the vault, and 0.21 m (0.7 ft) east of the west edge
of the vault.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 7 of 10
Station ID: 9414750 PUBLICATION DATE: 10/07/2011
Name: ALAMEDA, SAN FRANCISCO BAY
CA
NOAA Chart: 18649 Latitude: 37° 46.3' N ( 37.77167)
USGS Quad: OAKLAND WEST Longitude: 122° 17.9' W (-122.29833)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 4750 T 1993
DESIGNATION: 941 4750 T
MONUMENTATION: Tidal Station disk VM#: 11531
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete foundation OPUS PID:
LATITUDE: 37° 46.6' N ( 37.77642) LONGITUDE: 122° 17.9' W (-122.29861)
The bench mark is a disk cemented flush in the NE corner of the concrete
foundation of the loading ramp leading to the SIMA dive locker (Bldg NO 64)
located at Alameda Naval Air Station, on the West side of Ferry Point Road at
the SE corner of the lagoon, 20.00 m (65.6 ft) SSW of a manhole cover on the
inside corner of Ferry Point Road where it curves from NE to north, 15.94 m
(52.3 ft) north of a water valve cover near the center of Ferry Point Road,
10.62 m (34.8 ft) SE of the NE corner of Building NO 64, 0.19 m (0.6 ft) west of
the east edge of a concrete foundation, and 0.15 m (0.5 ft) south of the north
edge.
BENCH MARK STAMPING: 4750 U 2003
DESIGNATION: 941 4750 U
MONUMENTATION: Tidal Station disk VM#: 17385
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete footing OPUS PID:
LATITUDE: 37° 46.6' N ( 37.77733) LONGITUDE: 122° 17.9' W (-122.29847)
The bench mark is a disk set flush in a 1.82 m x 2.12 m (6.0 ft x 7.0 ft) con
base for a bollard located on former Alameda Air Station property, 17.35 m (56.9
ft) west of Ferry Point Rd, 8.73 m (28.6 ft) south of the south corner of a
wooden dock, 0.65 m (2.1 ft) east of the west edge of the bollard, 0.13 m (0.4
ft) north of the south edge of the foundation.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 8 of 10
Station ID: 9414750 PUBLICATION DATE: 10/07/2011
Name: ALAMEDA, SAN FRANCISCO BAY
CA
NOAA Chart: 18649 Latitude: 37° 46.3' N ( 37.77167)
USGS Quad: OAKLAND WEST Longitude: 122° 17.9' W (-122.29833)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 4750 W 2007
DESIGNATION: 941 4750 W
MONUMENTATION: Tidal Station disk VM#: 18484
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID#: BBDZ57
LATITUDE: 37° 46.3' N ( 37.77208) LONGITUDE: 122° 17.9' W (-122.29792)
The bench mark is the datum point of a deep rod located 42.93 m (140.8 ft) NE of
benchmark 941 4750 S, 41.8 m (137.2 ft) north of utility box # 592 at the edge
of a sand field, 23.32 m (76.5 ft) south of electrical box # L1542 on the north
side of W. Hornet Ave, and 1.12 m (3.7 ft) east of the eastern curb of an
alleyway. The datum point is set 7.5 cm (0.3 ft) below ground, being the top of
a steel rod driven 14.63 m (48.0 ft) to refusal, in a sleeve extending to a
depth of 0.92 m (3.0 ft) and encased in a 6" PVC pipe with a 5-inch (NOS/NGS)
logo cap.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 9 of 10
Station ID: 9414750 PUBLICATION DATE: 10/07/2011
Name: ALAMEDA, SAN FRANCISCO BAY
CA
NOAA Chart: 18649 Latitude: 37° 46.3' N ( 37.77167)
USGS Quad: OAKLAND WEST Longitude: 122° 17.9' W (-122.29833)
T I D A L D A T U M S
Tidal datums at ALAMEDA, SAN FRANCISCO BAY based on:
LENGTH OF SERIES: 19 YEARS
TIME PERIOD: January 1983 - December 2001
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION:
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
HIGHEST OBSERVED WATER LEVEL (12/03/1983) = 2.940
MEAN HIGHER HIGH WATER MHHW = 2.010
MEAN HIGH WATER MHW = 1.821
MEAN TIDE LEVEL MTL = 1.083
MEAN SEA LEVEL MSL = 1.051
MEAN LOW WATER MLW = 0.345
North American Vertical Datum NAVD88 = 0.070
MEAN LOWER LOW WATER MLLW = 0.000
LOWEST OBSERVED WATER LEVEL (01/11/2009) = -0.784
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
NO 8 1939 3.779 1.957
NO 7 1939 2.849 1.028
NO 11 1972 4.136 2.315
NO 12 1972 4.557 2.736
4750 P 1976 3.622 1.800
4750 Q 1976 3.242 1.421
LAGOON 3.177 1.356
WATER TANK NORTH 4.463 2.642
4750 S 1993 3.507 1.686
4750 T 1993 3.548 1.727
4750 U 2003 3.344 1.523
4750 W 2007 4.038 2.217
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 10 of 10
Station ID: 9414750 PUBLICATION DATE: 10/07/2011
Name: ALAMEDA, SAN FRANCISCO BAY
CA
NOAA Chart: 18649 Latitude: 37° 46.3' N ( 37.77167)
USGS Quad: OAKLAND WEST Longitude: 122° 17.9' W (-122.29833)
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.