U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 8
Station ID: 9410120 PUBLICATION DATE: 10/30/2003
Name: IMPERIAL BEACH, PACIFIC OCEAN
CA
NOAA Chart: 18772 Latitude: 32° 34.7' N ( 32.57830)
USGS Quad: IMPERIAL BEACH Longitude: 117° 8.1' W (-117.13500)
To reach the tidal bench marks from the intersection of Interstate Highway 5 and
Palm Avenue (State Highway 75), proceed west on Palm Avenue for about 4.0 km
(2.5 mi) to 1st Street, turn left on 1st Street and continue south for 0.5 km
(0.3 mi) to Imperial Beach Municipal Pier. The bench marks are located in the
vicinity of the pier, on Mar Vista High School grounds, on the elementary school
grounds, and along Palm Avenue. The tide gage and staff were located at the
west end of the pier.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: TIDAL 4 1972
DESIGNATION: 941 0120 TIDAL 4
MONUMENTATION: Tidal Station disk VM#: 7952
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: DC1339
SETTING CLASSIFICATION: Concrete curb OPUS PID:
LATITUDE: 32° 34.7' N ( 32.57830) LONGITUDE: 117° 7.9' W (-117.13200)
The primary bench mark is a disk set in the north curb of Elder Avenue, 31.70 m
(104.0 ft) WNW of the intersection of Elder Avenue and 1st Street, and 0.61 m
(2.0 ft) ESE of a "TWO HOUR PARKING" sign along the south side of a parking lot.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 8
Station ID: 9410120 PUBLICATION DATE: 10/30/2003
Name: IMPERIAL BEACH, PACIFIC OCEAN
CA
NOAA Chart: 18772 Latitude: 32° 34.7' N ( 32.57830)
USGS Quad: IMPERIAL BEACH Longitude: 117° 8.1' W (-117.13500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: TIDAL BM 6 1974
DESIGNATION: 941 0120 TIDAL 6
MONUMENTATION: Tidal Station disk VM#: 7953
AGENCY: National Ocean Survey (NOS) IDB PID#: DC1343
SETTING CLASSIFICATION: Concrete sidewalk OPUS PID:
LATITUDE: 32° 34.7' N ( 32.57830) LONGITUDE: 117° 8.1' W (-117.13500)
The bench mark is a disk set in the concrete sidewalk in the SW quadrant of the
intersection of 3rd Street and Evergreen Avenue, 3 m (10 ft) NNW of telephone
pole #5415324, 0.45 m (1.5 ft) SW of the curving edge of the curb, and 0.15 m
(0.5 ft) above the pavement level.
BENCH MARK STAMPING: TIDAL BM 7 1974
DESIGNATION: 941 0120 TIDAL 7
MONUMENTATION: Tidal Station disk VM#: 7954
AGENCY: National Ocean Survey (NOS) IDB PID#: DC1337
SETTING CLASSIFICATION: Concrete flagpole base OPUS PID:
LATITUDE: 32° 34.8' N ( 32.58000) LONGITUDE: 117° 7.3' W (-117.12200)
The bench mark is a disk set in the top of a concrete flagpole base in front of
Mar Vista High School, near the intersection of Encina Avenue and 5th Street, 52
m (170 ft) east of the extended centerline of 5th Street, 23.44 m (76.9 ft)
south of the centerline of Encina Avenue, 1.31 m (4.3 ft) north of a flagpole,
and 0.24 m (0.8 ft) above the walkway.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 8
Station ID: 9410120 PUBLICATION DATE: 10/30/2003
Name: IMPERIAL BEACH, PACIFIC OCEAN
CA
NOAA Chart: 18772 Latitude: 32° 34.7' N ( 32.57830)
USGS Quad: IMPERIAL BEACH Longitude: 117° 8.1' W (-117.13500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: TIDAL BM 8 1974
DESIGNATION: 941 0120 TIDAL 8
MONUMENTATION: Tidal Station disk VM#: 7955
AGENCY: National Ocean Survey (NOS) IDB PID#: DC1335
SETTING CLASSIFICATION: Concrete sidewalk OPUS PID:
LATITUDE: 32° 34.8' N ( 32.58000) LONGITUDE: 117° 6.9' W (-117.11500)
The bench mark is a disk set in the top of a concrete sidewalk at the T
intersection of Encina Avenue and 8th Street on the south side of Encina Avenue
along the extended centerline of 8th Street, 84 m (275 ft) north of the north
wall of the Boys Club building, 10 m (33 ft) ESE of pole #88689, and 6.40 m
(21.0 ft) south of the centerline of Encina Avenue.
BENCH MARK STAMPING: TIDAL BM 9 1974
DESIGNATION: 941 0120 TIDAL 9
MONUMENTATION: Tidal Station disk VM#: 7956
AGENCY: National Ocean Survey (NOS) IDB PID#: DC1334
SETTING CLASSIFICATION: Loading dock OPUS PID:
LATITUDE: 32° 35.0' N ( 32.58330) LONGITUDE: 117° 6.8' W (-117.11300)
The bench mark is a disk set in the top of the post office loading platform at
the intersection of Donax Avenue and Emory Street, 32 m (105 ft) north of the
north curb of Donax Avenue, 16.70 m (54.8 ft) west of the west curb of Emory
Street, 3.54 m (11.6 ft) north of the south end of the loading platform, 0.24 m
(0.8 ft) west of the east edge of the platform, and 0.24 m (0.8 ft) above the
pavement.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 8
Station ID: 9410120 PUBLICATION DATE: 10/30/2003
Name: IMPERIAL BEACH, PACIFIC OCEAN
CA
NOAA Chart: 18772 Latitude: 32° 34.7' N ( 32.57830)
USGS Quad: IMPERIAL BEACH Longitude: 117° 8.1' W (-117.13500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 0120 P 1977
DESIGNATION: 941 0120 P TIDAL
MONUMENTATION: Tidal Station disk VM#: 7958
AGENCY: National Ocean Survey (NOS) IDB PID#: DC1340
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID:
LATITUDE: 32° 34.8' N ( 32.58000) LONGITUDE: 117° 7.9' W (-117.13200)
The bench mark is a disk located in the vicinity of the Imperial Beach Municipal
Pier, 25.15 m (82.5 ft) NE of the shoreward end of the pier, 6.86 m (22.5 ft)
north of the centerline of Evergreen Street, 3.51 m (11.5 ft) SE of the SW
corner of the pier bathroom facilities building, and 1.89 m (6.2 ft) north of
the north curb of Evergreen Street. The bench mark is set level with the
ground, crimped to the top of a copper-clad rod driven 17.1 m (56 ft) to
refusal, and encased in a 4-inch PVC pipe.
BENCH MARK STAMPING: 0120 Q 1977
DESIGNATION: 941 0120 Q TIDAL
MONUMENTATION: Tidal Station disk VM#: 7959
AGENCY: National Ocean Survey (NOS) IDB PID#: DC1338
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID#: DC1338
LATITUDE: 32° 34.8' N ( 32.58000) LONGITUDE: 117° 7.5' W (-117.12500)
The bench mark is a disk located 0.8 km (0.5 mi) east of the beach in the NW
corner of Mar Vista High School grounds, 57 m (188 ft) east of the centerline of
4th Street, 20.57 m (67.5 ft) south of the chain link fence bordering the
school, and 14 m (46 ft) south of the centerline of Encina Avenue. The bench
mark is set level with the ground, crimped to the top of a copper-clad rod
driven 4.6 m (15 ft) to refusal, and encased in a 4-inch PVC pipe.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 8
Station ID: 9410120 PUBLICATION DATE: 10/30/2003
Name: IMPERIAL BEACH, PACIFIC OCEAN
CA
NOAA Chart: 18772 Latitude: 32° 34.7' N ( 32.57830)
USGS Quad: IMPERIAL BEACH Longitude: 117° 8.1' W (-117.13500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 0120 R 1977
DESIGNATION: 941 0120 R TIDAL
MONUMENTATION: Tidal Station disk VM#: 7960
AGENCY: National Ocean Survey (NOS) IDB PID#: DC1336
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID:
LATITUDE: 32° 34.8' N ( 32.58000) LONGITUDE: 117° 7.1' W (-117.11800)
The bench mark is a disk located 1.3 km (0.8 mi) east of the beach on Encina
Avenue, in the NE corner of the elementary school grounds, 18 m (60 ft) west of
the centerline of Connecticut Street, 15 m (49 ft) south of the centerline of
Encina Avenue, and 1.37 m (4.5 ft) north of the fence surrounding the school.
The bench mark is set level with the ground, crimped to the top of an
unspecified rod driven 16.5 m (54 ft) to refusal, and encased in a 4-inch PVC
pipe.
BENCH MARK STAMPING:
DESIGNATION: 941 0120 TIDAL 10
ALIAS: 10
MONUMENTATION: Survey disk VM#: 7961
AGENCY: California Department of Transportation
(CADT) IDB PID#:
SETTING CLASSIFICATION: Concrete pavement OPUS PID:
LATITUDE: 32° 35.0' N ( 32.58330) LONGITUDE: 117° 6.8' W (-117.11300)
The bench mark is a disk set under a 0.18 m (0.6 ft) metal cover flush with the
pavement in the median barrier at the intersection of Palm Avenue and Emory
Street, 16.76 m (55.0 ft) east of the centerline of Emory Street, exactly on the
centerline of the median barrier, and 0.06 m (0.2 ft) below the median barrier
pavement.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 8
Station ID: 9410120 PUBLICATION DATE: 10/30/2003
Name: IMPERIAL BEACH, PACIFIC OCEAN
CA
NOAA Chart: 18772 Latitude: 32° 34.7' N ( 32.57830)
USGS Quad: IMPERIAL BEACH Longitude: 117° 8.1' W (-117.13500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING:
DESIGNATION: 941 0120 TIDAL 12
ALIAS: 12
MONUMENTATION: Survey disk VM#: 7962
AGENCY: California Department of Transportation
(CADT) IDB PID#:
SETTING CLASSIFICATION: Concrete pavement OPUS PID:
LATITUDE: 32° 34.7' N ( 32.57830) LONGITUDE: 117° 8.1' W (-117.13500)
The bench mark is a disk set under a 0.15 m (0.5 ft) metal cover at the
intersection of Palm Avenue and Florida Street, on the north edge of the east
bound left turn only lane of Palm Avenue, 5.49 m (18.0 ft) west of the western
tip of the median barrier, and 0.06 m (0.2 ft) below the road pavement.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 7 of 8
Station ID: 9410120 PUBLICATION DATE: 10/30/2003
Name: IMPERIAL BEACH, PACIFIC OCEAN
CA
NOAA Chart: 18772 Latitude: 32° 34.7' N ( 32.57830)
USGS Quad: IMPERIAL BEACH Longitude: 117° 8.1' W (-117.13500)
T I D A L D A T U M S
Tidal datums at IMPERIAL BEACH, PACIFIC OCEAN based on:
LENGTH OF SERIES: 3 YEARS
TIME PERIOD: January 1976 - December 1978
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 9410170 SAN DIEGO, SAN DIEGO BAY
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
HIGHEST OBSERVED WATER LEVEL (12/20/1972) = 2.283
MEAN HIGHER HIGH WATER MHHW = 1.637
MEAN HIGH WATER MHW = 1.414
MEAN TIDE LEVEL MTL = 0.844
MEAN SEA LEVEL MSL = 0.839
MEAN LOW WATER MLW = 0.274
North American Vertical Datum NAVD88 = 0.074
MEAN LOWER LOW WATER MLLW = 0.000
LOWEST OBSERVED WATER LEVEL (01/26/1971) = -0.673
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
TIDAL 4 1972 4.402 2.988
TIDAL BM 6 1974 7.241 5.827
TIDAL BM 7 1974 5.762 4.348
TIDAL BM 8 1974 7.043 5.629
TIDAL BM 9 1974 7.097 5.683
0120 P 1977 4.405 2.991
0120 Q 1977 7.379 5.965
0120 R 1977 8.832 7.418
941 0120 TIDAL 10 6.615 5.201
941 0120 TIDAL 12 7.586 6.172
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 8 of 8
Station ID: 9410120 PUBLICATION DATE: 10/30/2003
Name: IMPERIAL BEACH, PACIFIC OCEAN
CA
NOAA Chart: 18772 Latitude: 32° 34.7' N ( 32.57830)
USGS Quad: IMPERIAL BEACH Longitude: 117° 8.1' W (-117.13500)
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.