U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 9410155 PUBLICATION DATE: 12/10/2015
Name: BALLAST POINT
CA
NOAA Chart: 18773 Latitude: 32° 41.2' N ( 32.68670)
USGS Quad: Point Loma Longitude: 117° 14.0' W (-117.23300)
To reach the tidal bench marks from the entrance of the Ballast Point Coast
Guard Station at the U.S. Navy Submarine base facility on Point Loma, proceed NW
for 27 m (90 ft) to the foot of the Search and Rescue pier, and proceed across
the concrete access bridge to the wooden pier. The bench marks are located on
the U.S. Navy Submarine base facility around the Search and Rescue pier. The
tide gage and staff were located on the north end of the Search and Rescue pier.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 0155 A 1983
DESIGNATION: 941 0155 A
MONUMENTATION: TIDAL STATION DISK VM#: 7968
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete pad OPUS PID:
LATITUDE: 32° 41.2' N ( 32.68669) LONGITUDE: 117° 14.0' W (-117.23300)
The primary bench mark is a disk set in a rectangular concrete pad at the SE
corner of the Administration Building of the Ballast Point Coast Guard station,
53.80 m (176.5 ft) west of bench mark NO STAMPING 1, 16 m (52 ft) east of the
south corner of the foot of the auxillary small boat pier, 15 m (48 ft) NE of
bench mark NO STAMPING 2, 0.3 m (1 ft) NW of the SE edge of the concrete slab,
and 0.3 m (1 ft) SW of the SW wall of the Administrative Building.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 9410155 PUBLICATION DATE: 12/10/2015
Name: BALLAST POINT
CA
NOAA Chart: 18773 Latitude: 32° 41.2' N ( 32.68670)
USGS Quad: Point Loma Longitude: 117° 14.0' W (-117.23300)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 0155 B 1983
DESIGNATION: 941 0155 B
MONUMENTATION: TIDAL STATION DISK VM#: 7969
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete pad OPUS PID:
LATITUDE: 32° 41.2' N ( 32.68669) LONGITUDE: 117° 14.0' W (-117.23300)
The bench mark is a disk set in a hexagonal concrete slab that forms the base of
a flagpole in front of Building Number 1, 63 m (207 ft) north of the north
corner of the base garage, 43 m (142 ft) SW of the Ballast Point Light B, 35 m
(115 ft) north of fire hydrant #1128, 18 m (58 ft) NE of the U.S. Coast Guard
CPO housing building, 5 m (17 ft) SE of the south corner of building number 1,
and 0.24 m (0.8 ft) north of the south edge of the concrete pad.
BENCH MARK STAMPING: V 734 RESET 1962
DESIGNATION: 941 0155 V 734 RESET
MONUMENTATION: TIDAL STATION DISK VM#: 7970
AGENCY: National Ocean Survey (NOS) IDB PID#: DC0795
SETTING CLASSIFICATION: Concrete slab OPUS PID:
LATITUDE: 32° 41.2' N ( 32.68669) LONGITUDE: 117° 14.0' W (-117.23300)
The bench mark is a disk set in a raised square concrete slab, 38 m (125 ft)
west of fire hydrant #1128, 36 m (117 ft) north of fire hydrant #1127, 30 m (97
ft) east of the west side of the concrete perimeter surrounding the Ballast
Point Coast Guard station, 28 m (91 ft) SE of the SW corner of the CPO housing
building, 2.07 m (6.8 ft) NE of the NE corner of the pump station, and 0.15 m
(0.5 ft) NW of the SW edge of the concrete slab.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 9410155 PUBLICATION DATE: 12/10/2015
Name: BALLAST POINT
CA
NOAA Chart: 18773 Latitude: 32° 41.2' N ( 32.68670)
USGS Quad: Point Loma Longitude: 117° 14.0' W (-117.23300)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING:
DESIGNATION: 941 0155 NO STAMPING 1
MONUMENTATION: TIDAL STATION DISK VM#: 7971
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 32° 41.2' N ( 32.68669) LONGITUDE: 117° 14.0' W (-117.23300)
The bench mark is a disk set flush in a concrete monument located on the NE edge
of the ninety degree curve of the dirt road that accesses the ruins of the twin
gun battery turrets, 53.80 m (176.5 ft) SE of bench mark 94 0155 A, 52 m (170
ft) south of fire hydrant #1127, 37 m (120 ft) SE of the SE corner of the
Administrative Building, 21 m (69 ft) NE of the north entrance to a bunker
located between the twin gun battery ruins, and 10 m (30 ft) NE of the center of
the north gun battery turret.
BENCH MARK STAMPING:
DESIGNATION: 941 0155 NO STAMPING 2
MONUMENTATION: TIDAL STATION DISK VM#: 7972
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 32° 41.2' N ( 32.68669) LONGITUDE: 117° 14.0' W (-117.23300)
The bench mark is a disk set in a concrete monument located on the edge of the
rocks south of the Administrative Building, 54.99 m (180.4 ft) west of bench
mark NO STAMPING 1, 37 m (123 ft) south of the south corner of the foot of the
Search and Rescue pier, 38 m (110 ft) west of the centerline of an unnamed base
entrance road, 18 m (60 ft) NE of the south corner of the foot of the auxillary
boat pier, and 15 m (48 ft) SW of bench mark 941 0155 A.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 9410155 PUBLICATION DATE: 12/10/2015
Name: BALLAST POINT
CA
NOAA Chart: 18773 Latitude: 32° 41.2' N ( 32.68670)
USGS Quad: Point Loma Longitude: 117° 14.0' W (-117.23300)
T I D A L D A T U M S
Tidal datums at BALLAST POINT based on:
LENGTH OF SERIES: 30 Days
TIME PERIOD: Aug. 29, 1983 - Sep. 27, 1983
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 9410230 LA JOLLA, PACIFIC OCEAN
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METER:
MEAN HIGHER HIGH WATER MHHW = 1.672
MEAN HIGH WATER MHW = 1.451
MEAN TIDE LEVEL MTL = 0.860
MEAN SEA LEVEL MSL = 0.855
MEAN LOW WATER MLW = 0.269
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METER above:
Stamping or Designation MLLW MHW
0155 A 1983 2.741 1.289
0155 B 1983 2.664 1.212
V 734 RESET 1962 2.460 1.008
941 0155 NO STAMPING 1 4.306 2.854
941 0155 NO STAMPING 2 2.414 0.962
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 9410155 PUBLICATION DATE: 12/10/2015
Name: BALLAST POINT
CA
NOAA Chart: 18773 Latitude: 32° 41.2' N ( 32.68670)
USGS Quad: Point Loma Longitude: 117° 14.0' W (-117.23300)
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.