U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 6
Station ID: 8761198 PUBLICATION DATE: 04/13/2018
Name: CHEVRON STATION 289, PELICAN ISLAND
LA
NOAA Chart: 11358 Latitude: 29° 16.0' N ( 29.26670)
USGS Quad: BURAS Longitude: 89° 35.9' W ( -89.59830)
To reach the tidal bench marks from the Buras Boat Harbor off State Highway 23
in Buras, proceed by boat NE on a dredged canal to Bayou Long, then south on
Bayou Long to Bayou Fontanelle, then proceed south on Bayou Fontanelle to the
dredged canal 0.8 km (0.5 mi) north of the jetties on the Gulf of Mexico, then
east on the dredged canal to Chevron Station 289. The bench marks are on the
levee around the storage tanks. The tide gage and staff were on the fuel dock
which is near the SW corner of the Chevron complex.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 1198 A 1985
DESIGNATION: 876 1198 A TIDAL
MONUMENTATION: Tidal Station disk VM#: 7135
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 29° 16.0' N ( 29.26670) LONGITUDE: 89° 35.9' W ( -89.59830)
The primary bench mark is a disk located near the SE corner of the levee, 22 m
(72 ft) NE of a flag pole, 12.62 m (41.4 ft) NW of a fire extinguisher at the
valve station near the SE corner of the complex, 4.21 m (13.8 ft) SE of a 1-inch
galvanized iron pipe driven in the ground at the base of the levee, and 0.30 m
(1.0 ft) ESE of a witness post. The bench mark is set 9 cm (0.3 ft) below
ground level, crimped to the top of a stainless steel rod driven 20.7 m (68 ft)
to refusal, and encased in a 5-inch PVC pipe and concrete kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 6
Station ID: 8761198 PUBLICATION DATE: 04/13/2018
Name: CHEVRON STATION 289, PELICAN ISLAND
LA
NOAA Chart: 11358 Latitude: 29° 16.0' N ( 29.26670)
USGS Quad: BURAS Longitude: 89° 35.9' W ( -89.59830)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1198 B 1985
DESIGNATION: 876 1198 B TIDAL
MONUMENTATION: Tidal Station disk VM#: 7136
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 29° 16.0' N ( 29.26670) LONGITUDE: 89° 35.9' W ( -89.59830)
The bench mark is a disk located on the east side of the levee about midway
between bench marks 1198 A 1985 and 1198 C 1985, 75.29 m (247.0 ft) north of
bench mark 1198 A 1985, 47 m (153 ft) NE of the edge of the walkway of tank
#32284, 37 m (120 ft) SE of the edge of the walkway of tank #30501, 2.29 m (7.5
ft) west of the centerline of the levee, and 0.30 m (1.0 ft) east of a witness
post. The bench mark is set 9 cm (0.3 ft) below ground level, crimped to the
top of a stainless steel rod driven 21.9 m (72 ft) to refusal, and encased in a
5-inch PVC pipe and concrete kickblock.
BENCH MARK STAMPING: 1198 C 1985
DESIGNATION: 876 1198 C TIDAL
MONUMENTATION: Tidal Station disk VM#: 7137
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 29° 16.0' N ( 29.26670) LONGITUDE: 89° 35.9' W ( -89.59830)
The bench mark is a disk located near the NE corner of the levee, 92 m (302 ft)
north of bench mark 1198 B 1985, 9.57 m (31.4 ft) NW of an existing piling at
the outside base of the levee, 6.58 m (21.6 ft) SE of a piling at the base of
the levee that supports an old abandoned walkway, 2.29 m (7.5 ft) SW of the
centerline of the levee, and 0.37 m (1.2 ft) east of a witness post. The bench
mark is set 9 cm (0.3 ft) below ground level, crimped to the top of a stainless
steel rod driven 19.5 m (64 ft) to refusal, and encased in a 5-inch PVC pipe and
kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 6
Station ID: 8761198 PUBLICATION DATE: 04/13/2018
Name: CHEVRON STATION 289, PELICAN ISLAND
LA
NOAA Chart: 11358 Latitude: 29° 16.0' N ( 29.26670)
USGS Quad: BURAS Longitude: 89° 35.9' W ( -89.59830)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1198 D 1985
DESIGNATION: 876 1198 D TIDAL
MONUMENTATION: Tidal Station disk VM#: 7138
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 29° 16.0' N ( 29.26670) LONGITUDE: 89° 35.9' W ( -89.59830)
The bench mark is a disk located near the NW corner of the levee, 80.47 m (264.0
ft) west of bench mark 1198 C 1985, 45.57 m (149.5 ft) SE of the southernmost
light pole on the levee that runs northwesterly to the pit, 23.84 m (78.2 ft) NW
of the electric pump near Tank #30502, 16.03 m (52.6 ft) north of the north edge
of a steel walkway at its intersection with the levee, and 0.40 m (1.3 ft) SW of
a witness post. The bench mark is set 9 cm (0.3 ft) below ground level, crimped
to the top of a stainless steel rod driven 19.5 m (64 ft) to refusal, and
encased in a 5-inch PVC pipe and concrete kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 6
Station ID: 8761198 PUBLICATION DATE: 04/13/2018
Name: CHEVRON STATION 289, PELICAN ISLAND
LA
NOAA Chart: 11358 Latitude: 29° 16.0' N ( 29.26670)
USGS Quad: BURAS Longitude: 89° 35.9' W ( -89.59830)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1198 E 1985
DESIGNATION: 876 1198 E TIDAL
MONUMENTATION: Tidal Station disk VM#: 7139
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 29° 16.0' N ( 29.26670) LONGITUDE: 89° 35.9' W ( -89.59830)
The bench mark is a disk located near the middle of the west side of the levee,
76.11 m (249.7 ft) south of bench mark 1198 D 1985, 46.21 m (151.6 ft) north of
the north edge of the walkway leading to the heliport, 19.42 m (63.7 ft) SSW of
the first light pole north of the light pole at the intersection of the walkways
to tank #30501, 18.99 m (62.3 ft) SW of the light pole at the intersection of
the walkways leading to tank #30501, and 0.61 m (2.0 ft) west of a witness post.
The bench mark is set 9 cm (0.3 ft) below ground level, crimped to the top of a
stainless steel rod driven 19.5 m (64 ft) to refusal, and encased in a 5-inch
PVC pipe and concrete kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 6
Station ID: 8761198 PUBLICATION DATE: 04/13/2018
Name: CHEVRON STATION 289, PELICAN ISLAND
LA
NOAA Chart: 11358 Latitude: 29° 16.0' N ( 29.26670)
USGS Quad: BURAS Longitude: 89° 35.9' W ( -89.59830)
T I D A L D A T U M S
Tidal datums at CHEVRON STATION 289, PELICAN ISLAND based on:
LENGTH OF SERIES: 8 MONTHS
TIME PERIOD: November 1985 - June 1986
TIDAL EPOCH: 2012-2016
CONTROL TIDE STATION: 8761724 GRAND ISLE, EAST POINT
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 0.340
MEAN HIGH WATER MHW = 0.338
MEAN SEA LEVEL MSL = 0.173
MEAN TIDE LEVEL MTL = 0.171
MEAN LOW WATER MLW = 0.004
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
1198 A 1985 0.955 0.617
1198 B 1985 -0.123 -0.461
1198 C 1985 -0.002 -0.340
1198 D 1985 0.442 0.104
1198 E 1985 0.951 0.613
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 6
Station ID: 8761198 PUBLICATION DATE: 04/13/2018
Name: CHEVRON STATION 289, PELICAN ISLAND
LA
NOAA Chart: 11358 Latitude: 29° 16.0' N ( 29.26670)
USGS Quad: BURAS Longitude: 89° 35.9' W ( -89.59830)
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.