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Datums Page Page 1 of 7
Station ID: 9412110 PUBLICATION DATE: 04/21/2003
Name: PORT SAN LUIS, PACIFIC OCEAN
CA
NOAA Chart: 18704 Latitude: 35° 10.6' N ( 35.17670)
USGS Quad: PORT SAN LUIS Longitude: 120° 45.6' W (-120.76000)
To reach the tidal bench marks, from north bound U.S. Highway 101 and Avila Road
(marked Avila Beach and Port San Luis Marina) proceed SW on Avila Road for about
7.2 km (4.5 mi) to Port San Luis Harbor District area and the pier just beyond
the Pacific Gas & Electric (PG&E) Nuclear Power Plant entrance. The tidal bench
marks are located on the Harbor District grounds, at the entrance to the power
plant, and along Avila Road. The tide gage is located in the ice house at the
end of the pier.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 6 1936
DESIGNATION: 941 2110 TIDAL 6
MONUMENTATION: Bench Mark disk VM#: 945
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: FV0898
SETTING CLASSIFICATION: Rock outcrop OPUS PID#: FV0898
LATITUDE: 35° 10.3' N ( 35.17097) LONGITUDE: 120° 45.4' W (-120.75603)
The primary bench mark is a disk set in the top of a rock outcrop at the inshore
end of the pier, 53 m (175 ft) SW of a flagpole, 17 m (55 ft) NE of the east guy
pole of the most eastern of two crabbing docks, 7.92 m (26.0 ft) ESE of a brass
fire hydrant surrounded by four metal posts at the SW corner of the pier, 2.38 m
(7.8 ft) SW of the SW edge of the pier, and 1 m (2 ft) below the pier floor, and
0.34 m (1.1 ft) SW of SW end of a 0.3 m (1 ft) square timber supporting the
inshore end of the wharf.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 7
Station ID: 9412110 PUBLICATION DATE: 04/21/2003
Name: PORT SAN LUIS, PACIFIC OCEAN
CA
NOAA Chart: 18704 Latitude: 35° 10.6' N ( 35.17670)
USGS Quad: PORT SAN LUIS Longitude: 120° 45.6' W (-120.76000)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 16 1973
DESIGNATION: 941 2110 TIDAL 16
MONUMENTATION: Tidal Station disk VM#: 948
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: FV1078
SETTING CLASSIFICATION: Concrete sea wall OPUS PID:
LATITUDE: 35° 10.3' N ( 35.17247) LONGITUDE: 120° 45.3' W (-120.75575)
The bench mark is a disk set flush in the top of a concrete sea wall at the NE
end of the Port San Luis wharf area, 7.96 m (26.1 ft) north of the NW corner of
a gasoline service station building, 2.83 m (9.3 ft) SE of the NW end of the
sea-wall, and 0.15 m (0.5 ft) SW of the NE face of the sea wall.
BENCH MARK STAMPING: TIDAL BM 18 1975
DESIGNATION: 941 2110 TIDAL 18
MONUMENTATION: Tidal Station disk VM#: 949
AGENCY: National Ocean Survey (NOS) IDB PID#: FV1077
SETTING CLASSIFICATION: Concrete pier OPUS PID:
LATITUDE: 35° 10.3' N ( 35.17169) LONGITUDE: 120° 45.3' W (-120.75572)
The bench mark is a disk set flush in the SW corner of a concrete base for a
marine hoist, 72 m (237 ft) north of the inshore end of the Port San Luis wharf,
12.13 m (39.8 ft) NE from southern gate post, and 0.15 m (0.5 ft) NE of the SW
edge of pier.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 7
Station ID: 9412110 PUBLICATION DATE: 04/21/2003
Name: PORT SAN LUIS, PACIFIC OCEAN
CA
NOAA Chart: 18704 Latitude: 35° 10.6' N ( 35.17670)
USGS Quad: PORT SAN LUIS Longitude: 120° 45.6' W (-120.76000)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: TIDAL BM 20 1975
DESIGNATION: 941 2110 TIDAL 20
MONUMENTATION: Tidal Station disk VM#: 950
AGENCY: National Ocean Survey (NOS) IDB PID#: FV1079
SETTING CLASSIFICATION: Concrete culvert OPUS PID:
LATITUDE: 35° 10.5' N ( 35.17500) LONGITUDE: 120° 45.3' W (-120.75558)
The bench mark is a disk set flush in a concrete culvert south of the entrance
to the Pacific Gas & Electric (PG&E) Nuclear Power Plant, 40 m (132 ft) WSW of a
movable guard house, 20 m (65 ft) west of the centerline of Port San Luis Road,
8 m (27 ft) south of the centerline of the PG&E entrance road, and 1 m (2 ft)
north of a lightpole.
BENCH MARK STAMPING: 2110 A 1982
DESIGNATION: 941 2110 A TIDAL
MONUMENTATION: Tidal Station disk VM#: 951
AGENCY: National Ocean Survey (NOS) IDB PID#: FV1991
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 35° 10.4' N ( 35.17275) LONGITUDE: 120° 45.4' W (-120.75617)
The bench mark is a disk, located at the north end of the traffic island at the
Y junction entrance to Port San Luis Harbor District Area, 8 m (27 ft) west of
the centerline of the road leading to the fuel dock, 6 m (19 ft) east of the
centerline of the main entrance road, and 2.99 m (9.8 ft) NW of the center of a
large 1.01 m (3.3 ft) diameter manhole cover. The bench mark is set 15 cm (0.5
ft) above ground, crimped to a stainless steel rod driven 4.3 m (14 ft) to
refusal, and surrounded by a 4-inch PVC pipe.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 7
Station ID: 9412110 PUBLICATION DATE: 04/21/2003
Name: PORT SAN LUIS, PACIFIC OCEAN
CA
NOAA Chart: 18704 Latitude: 35° 10.6' N ( 35.17670)
USGS Quad: PORT SAN LUIS Longitude: 120° 45.6' W (-120.76000)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 2110 D 1982
DESIGNATION: 941 2110 D TIDAL
MONUMENTATION: Tidal Station disk VM#: 953
AGENCY: National Ocean Survey (NOS) IDB PID#: FV1994
SETTING CLASSIFICATION: Concrete foundation OPUS PID:
LATITUDE: 35° 10.2' N ( 35.17069) LONGITUDE: 120° 45.4' W (-120.75628)
The bench mark is a disk set flush in the NE end of the southwesterly of two
identical fishing ramps facing the waterfront, 38.25 m (125.5 ft) SW of bench
mark 6 1936, 12.34 m (40.5 ft) NE of the SE corner of the fenced lot of Port San
Luis Harbor District maintenance Division, and 4.69 m (15.4 ft) SE of eastern
most pole of three metal poles blocking NE edge of boat ramp.
BENCH MARK STAMPING: NO 15 1971 RESET 1983
DESIGNATION: 941 2110 TIDAL 15 RESET
MONUMENTATION: Tidal Station disk VM#: 954
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: FV1993
SETTING CLASSIFICATION: Concrete walkway OPUS PID:
LATITUDE: 35° 10.3' N ( 35.17133) LONGITUDE: 120° 45.4' W (-120.75617)
The bench mark is a disk set flush in the concrete walkway surrounding the Port
San Luis Harbor Office building, 11.03 m (36.2 ft) SW of the NE corner of the
building, 1.10 m (3.6 ft) east of the street curbing, and 0.27 m (0.9 ft) south
of the NE corner of a 1 m (3 ft) wall across the entrance way to the Harbor
Office.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 7
Station ID: 9412110 PUBLICATION DATE: 04/21/2003
Name: PORT SAN LUIS, PACIFIC OCEAN
CA
NOAA Chart: 18704 Latitude: 35° 10.6' N ( 35.17670)
USGS Quad: PORT SAN LUIS Longitude: 120° 45.6' W (-120.76000)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: MAR 3 LS 3354
DESIGNATION: MAR 3
MONUMENTATION: Survey disk VM#: 955
AGENCY: Private firm IDB PID#: FV1992
SETTING CLASSIFICATION: Concrete walkway OPUS PID:
LATITUDE: 35° 10.3' N ( 35.17142) LONGITUDE: 120° 45.4' W (-120.75636)
The bench mark is a disk set flush in the concrete walkway surrounding the Port
San Luis Harbor Office building, 7.32 m (24.0 ft) ESE of the flag pole, 2.41 m
(7.9 ft) east of the NE corner of the building, and 0.49 m (1.6 ft) west of the
east corner of the red curbing of the walkway.
BENCH MARK STAMPING: 2110 E 2000
DESIGNATION: 941 2110 E
MONUMENTATION: Tidal Station disk VM#: 16190
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete vault OPUS PID:
LATITUDE: 35° 10.5' N ( 35.17553) LONGITUDE: 120° 45.2' W (-120.75411)
The bench mark is a disk set flush in the SW corner of a concrete utility vault
on north side of a road to Port San Luis Pier, east of the entrance to the
nuclear power plant, 6.71 m (22.0 ft) west of a No Parking sign, 4.27 m (14.0
ft) north of a centerline of the road, 0.24 m (0.8 ft) north of south edge of
the vault, and 0.24 m (0.8 ft) east of west edge of the vault.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 7
Station ID: 9412110 PUBLICATION DATE: 04/21/2003
Name: PORT SAN LUIS, PACIFIC OCEAN
CA
NOAA Chart: 18704 Latitude: 35° 10.6' N ( 35.17670)
USGS Quad: PORT SAN LUIS Longitude: 120° 45.6' W (-120.76000)
T I D A L D A T U M S
Tidal datums at PORT SAN LUIS, PACIFIC OCEAN 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 (01/18/1973) = 2.331
MEAN HIGHER HIGH WATER MHHW = 1.623
MEAN HIGH WATER MHW = 1.408
MEAN TIDE LEVEL MTL = 0.863
MEAN SEA LEVEL MSL = 0.853
MEAN LOW WATER MLW = 0.317
North American Vertical Datum NAVD88 = 0.024
MEAN LOWER LOW WATER MLLW = 0.000
LOWEST OBSERVED WATER LEVEL (01/07/1951) = -0.732
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
6 1936 4.395 2.987
NO 16 1973 2.839 1.431
TIDAL BM 18 1975 3.555 2.147
TIDAL BM 20 1975 10.146 8.738
2110 A 1982 4.628 3.220
2110 D 1982 3.416 2.008
NO 15 1971 RESET 1983 4.825 3.417
MAR 3 LS 3354 4.814 3.406
2110 E 2000 9.786 8.378
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 7 of 7
Station ID: 9412110 PUBLICATION DATE: 04/21/2003
Name: PORT SAN LUIS, PACIFIC OCEAN
CA
NOAA Chart: 18704 Latitude: 35° 10.6' N ( 35.17670)
USGS Quad: PORT SAN LUIS Longitude: 120° 45.6' W (-120.76000)
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.