U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
PUBLICATION DATE: 08/15/1983
Station ID: 9414513 SUPERCEDED DATE: 04/21/2003
Name: GRANITE ROCK, REDWOOD CREEK, SAN FRANCISCO BAY
CALIFORNIA
NOAA Chart: 18651 Latitude: 37° 29.7' N
USGS Quad: PALO ALTO Longitude: 122° 12.8' W
To reach the tidal bench marks from U.S. Highway 101 exit Harbor Boulevard
toward Redwood City taking first left after going under the freeway, then 0.10
mile (0.16 km) to Granite Rock Company property. The tide gage and staff were
located on the northeasternmost corner of the dock, and the bench marks are on
the Granite Rock Plant property and near Harbor Boulevard.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 4513 A 1976
MONUMENTATION: Survey Disk VM#: 8163
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Slab
The bench mark is set in the NE corner of the concrete slab base of an asphalt
plant (Granite Rock Plant on Blomquist Street off Harbor Boulevard), 241 feet
(73.5 m) south of the seawall along Smith Slough, 62.0 feet (18.9 m) south of
the south rail of a single line railroad track, 14 feet (4.3 m) WSW of the SW
corner of the batch room and 1.5 feet (0.5 m) north of the northernmost leg of
the baghouse.
BENCH MARK STAMPING: 4513 B 1976
MONUMENTATION: Survey Disk VM#: 8164
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Slab
The bench mark is set flush in the NE corner of a concrete slab base of a spray
rack at the Granite Rock plant on Blomquist Street off Harbor Boulevard, 138
feet (42 m) north of the shop building in center of the Granite Rock plantyard,
65 feet (19.8 m) east of the easternmost leg of the asphalt storage tanks, 62
feet (18.9 m) south of the south rail of a single railroad line, and 36 feet (11
m) NW of the NW corner of a corrugated steel shack.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
PUBLICATION DATE: 08/15/1983
Station ID: 9414513 SUPERCEDED DATE: 04/21/2003
Name: GRANITE ROCK, REDWOOD CREEK, SAN FRANCISCO BAY
CALIFORNIA
NOAA Chart: 18651 Latitude: 37° 29.7' N
USGS Quad: PALO ALTO Longitude: 122° 12.8' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 4513 C 1976
MONUMENTATION: Survey Disk VM#: 8165
AGENCY: PID:
SETTING CLASSIFICATION: Copper-Clad Steel Rod
The bench mark is located at the Granite Rock Company property on Harbor
Boulevard in Redwood City, 525 feet (160 m) west of the entrance road to Granite
Rock Company, 128 feet (39 m) SE of the SE corner of the Granite Rock office
building, 100 feet (30.5 m) west of the westernmost rail of a spur line that
ends at the entrance road, 3 feet (0.9 m) ENE of a fire hydrant on the north
side of a road along the front edge of the company property and level with the
ground. The bench mark is on a rod driven to 55 feet (16.8 m) and encased in a
PVC pipe.
BENCH MARK STAMPING: 4513 D 1976
MONUMENTATION: Survey Disk VM#: 8166
AGENCY: PID#: HT2321
SETTING CLASSIFICATION: Cooper-Clad Steel Rod
The bench mark is 280 feet (85.3 m) NNW of the center of the intersection of
East Bayshore Road and Harbor Boulevard and Granite Rock Company entrance road,
42 feet (12.8 m) south of the center of Harbor Boulevard, 27.5 feet (8.4 m) east
of the eaternmost rail of railroad tracks parallel to Harbor Boulevard, and 18.5
feet (5.6 m) east of a one lane road and level with the ground.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
PUBLICATION DATE: 08/15/1983
Station ID: 9414513 SUPERCEDED DATE: 04/21/2003
Name: GRANITE ROCK, REDWOOD CREEK, SAN FRANCISCO BAY
CALIFORNIA
NOAA Chart: 18651 Latitude: 37° 29.7' N
USGS Quad: PALO ALTO Longitude: 122° 12.8' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: T 984 1964
MONUMENTATION: Survey Disk VM#: 8167
AGENCY: PID#: HT1309
SETTING CLASSIFICATION: Concrete Foundation
The bench mark is in top of the NE corner of the concrete foundation for the NE
steel leg of the east one of two steel powerline towers, 153 feet (46.6 m) east
of the centerline of an asphalt road leading south to a Pacific Gas and Electric
sub station, 53 feet (16.2 m) west of the centerline of the west lanes of Harbor
Road, 53 feet (16.2 m) south of the centerline of a short east-west road, and 1
foot (0.3 m) below the roads.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
PUBLICATION DATE: 08/15/1983
Station ID: 9414513 SUPERCEDED DATE: 04/21/2003
Name: GRANITE ROCK, REDWOOD CREEK, SAN FRANCISCO BAY
CALIFORNIA
NOAA Chart: 18651 Latitude: 37° 29.7' N
USGS Quad: PALO ALTO Longitude: 122° 12.8' W
T I D A L D A T U M S
Tidal datums at GRANITE ROCK, REDWOOD CREEK, SAN FRANCISCO BAY based on:
LENGTH OF SERIES: 8 MONTHS
TIME PERIOD: JULY 1976 - FEBRUARY1977
TIDAL EPOCH: 1960-1978
CONTROL TIDE STATION: 9414523 REDWOOD CITY, CA
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET:
HIGHEST OBSERVED WATER LEVEL (11/22/1976) = 9.57
MEAN HIGHER HIGH WATER MHHW = 8.08
MEAN HIGH WATER MHW = 7.46
MEAN TIDE LEVEL MTL = 4.32
* NATIONAL GEODETIC VERTICAL DATUM NGVD29 = 3.96
MEAN LOW WATER MLW = 1.18
MEAN LOWER LOW WATER MLLW = 0.00
LOWEST OBSERVED WATER LEVEL (12/22/1976) = -1.60
* NGVD reference based on adjustment of 1976 and NOS levels of1976-1977.
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In FEET above:
Stamping or Designation MLLW MHW
4513 A 1976 12.22 4.76
4513 B 1976 12.61 5.15
4513 C 1976 10.02 2.56
4513 D 1976 10.26 2.80
T 984 1964 8.21 0.75
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
PUBLICATION DATE: 08/15/1983
Station ID: 9414513 SUPERCEDED DATE: 04/21/2003
Name: GRANITE ROCK, REDWOOD CREEK, SAN FRANCISCO BAY
CALIFORNIA
NOAA Chart: 18651 Latitude: 37° 29.7' N
USGS Quad: PALO ALTO Longitude: 122° 12.8' 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.