U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 7
Station ID: 8761679 PUBLICATION DATE: 04/16/2018
Name: ST. MARYS POINT, BARATARIA BAY
LA
NOAA Chart: 11358 Latitude: 29° 25.9' N ( 29.43170)
USGS Quad: WILKINSON BAY Longitude: 89° 56.3' W ( -89.93830)
To reach the tidal bench marks from Rigaud Marina at the east end of Grand Isle,
proceed by boat north along Barataria Bay Waterway for 18 km (11 mi) to Channel
Marker #34, then turn right between the islands and proceed east for 4.8 km (3.0
mi) to a camp at the north end of St. Marys Point Island. The bench marks are
in the vicinity of the camp and south along the island. The tide gage and staff
were located at the west end of the pier west of the camp at the north end of
the island.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 1679 A 1985
DESIGNATION: 876 1679 A TIDAL
MONUMENTATION: Tidal Station disk VM#: 7184
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 29° 25.9' N ( 29.43170) LONGITUDE: 89° 56.3' W ( -89.93830)
The primary bench mark is a disk located immediately south of the camp, 24.84 m
(81.5 ft) NNW of the southernmost pile having a spotlight on the west pier,
10.73 m (35.2 ft) south of the SW corner pile supporting the walkway around the
SW corner of the camp, 8 m (26 ft) west of the SW corner pile supporting a small
generator shed, 7.19 m (23.6 ft) SW of the face of the water tank on the south
side of the camp, and 0.37 m (1.2 ft) west of an NOS witness post. The bench
mark is set 0.55 m (1.8 ft) above 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 extending 0.70 m (2.3 ft) above ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 7
Station ID: 8761679 PUBLICATION DATE: 04/16/2018
Name: ST. MARYS POINT, BARATARIA BAY
LA
NOAA Chart: 11358 Latitude: 29° 25.9' N ( 29.43170)
USGS Quad: WILKINSON BAY Longitude: 89° 56.3' W ( -89.93830)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1679 B 1985
DESIGNATION: 876 1679 B TIDAL
MONUMENTATION: Tidal Station disk VM#: 7185
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 29° 25.9' N ( 29.43170) LONGITUDE: 89° 56.3' W ( -89.93830)
The bench mark is a disk located 76.29 m (250.3 ft) SSE of bench mark 1679 A
1985, 21 m (70 ft) NNE of a patch of dense reeds (PHRAGMITES COMMUNIS), 5 m (17
ft) WNW of the east shore of the island, 5 m (17 ft) ESE of the west shore of
the island, 4.57 m (15.0 ft) east of a 2-inch square wood post standing 2 m (7
ft) above the marsh, 4.33 m (14.2 ft) north of a 2-inch square wood post
standing 2 m (7 ft) above the marsh, and 0.3 (1.0 ft) west of an NOS witness
post. The bench mark is set 0.43 m (1.4 ft) above ground level, crimped to the
top of a stainless steel rod driven 20.7 m (68 ft) to substantial resistance,
and encased in a 5-inch PVC pipe extending 0.61 m (2.0 ft) above ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 7
Station ID: 8761679 PUBLICATION DATE: 04/16/2018
Name: ST. MARYS POINT, BARATARIA BAY
LA
NOAA Chart: 11358 Latitude: 29° 25.9' N ( 29.43170)
USGS Quad: WILKINSON BAY Longitude: 89° 56.3' W ( -89.93830)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1679 C 1985
DESIGNATION: 876 1679 C TIDAL
MONUMENTATION: Tidal Station disk VM#: 7186
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 29° 25.9' N ( 29.43170) LONGITUDE: 89° 56.3' W ( -89.93830)
The bench mark is a disk located 75.96 m (249.2 ft) south of bench mark 1679 B
1985, 15 m (48 ft) west of the east shore of the island, 13 m (42 ft) east of
the west shore of the island, 22.0 feet (6.7 m) east of a 2-inch square wood
post standing 2 m (7 ft) above the marsh, 5.27 m (17.3 ft) south of a 2-inch
square wood post standing 2 m (7 ft) above the marsh, and 0.3 (1.0 ft) west of
an NOS witness post. The bench mark is set 0.49 m (1.6 ft) above ground level,
crimped to the top of a stainless steel rod driven 20.7 m (68 ft) to substantial
resistance, and encased in a 5-inch PVC pipe extending 0.70 m (2.3 ft) above
ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 7
Station ID: 8761679 PUBLICATION DATE: 04/16/2018
Name: ST. MARYS POINT, BARATARIA BAY
LA
NOAA Chart: 11358 Latitude: 29° 25.9' N ( 29.43170)
USGS Quad: WILKINSON BAY Longitude: 89° 56.3' W ( -89.93830)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1679 D 1985
DESIGNATION: 876 1679 D TIDAL
MONUMENTATION: Tidal Station disk VM#: 7187
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 29° 25.9' N ( 29.43170) LONGITUDE: 89° 56.3' W ( -89.93830)
The bench mark is a disk located 75.71 m (248.4 ft) south of bench mark 1679 C
1985, 16 m (53 ft) west of the east shore of the island, 9 m (28 ft) ESE of the
west shore of the island, 3.54 m (11.6 ft) south of a 2-inch square wood post
standing 2 m (7 ft) above the marsh, 3.47 m (11.4 ft) ESE of a 2-inch square
wood post standing 2 m (7 ft) above the marsh, and 0.34 m (1.1 ft) west of an
NOS witness post. The bench mark is set 0.43 m (1.4 ft) above ground level
crimped to the top of a stainless steel rod driven 23.2 m (76 ft) to substantial
resistance, encased in a 5-inch PVC pipe extending 0.55 m (1.8 ft) above ground
level, and surrounded by a concrete kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 7
Station ID: 8761679 PUBLICATION DATE: 04/16/2018
Name: ST. MARYS POINT, BARATARIA BAY
LA
NOAA Chart: 11358 Latitude: 29° 25.9' N ( 29.43170)
USGS Quad: WILKINSON BAY Longitude: 89° 56.3' W ( -89.93830)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1679 E 1985
DESIGNATION: 876 1679 E TIDAL
MONUMENTATION: Tidal Station disk VM#: 7188
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 29° 25.9' N ( 29.43170) LONGITUDE: 89° 56.3' W ( -89.93830)
The bench mark is a disk located 75.65 m (248.2 ft) SSE of bench mark 1679 D
1985, 32 m (106 ft) east of the west shore of the island, 9 m (30 ft) west of
the east shore of the island, 4.18 m (13.7 ft) ENE of a 1-inch square wood stake
standing 2 m (7 ft) above the marsh, 4 m (13 ft) south of a cane pole standing 2
m (7 ft) above the marsh, and 0.46 m (1.5 ft) east of an NOS witness post. The
bench mark is set 0.34 m (1.1 ft) above ground level, crimped to the top of a
stainless steel rod driven 24.4 m (80 ft) to substantial resistance, encased in
a 5-inch PVC pipe extending 0.49 m (1.6 ft) above ground level, and surrounded
by a concrete kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 7
Station ID: 8761679 PUBLICATION DATE: 04/16/2018
Name: ST. MARYS POINT, BARATARIA BAY
LA
NOAA Chart: 11358 Latitude: 29° 25.9' N ( 29.43170)
USGS Quad: WILKINSON BAY Longitude: 89° 56.3' W ( -89.93830)
T I D A L D A T U M S
Tidal datums at ST. MARYS POINT, BARATARIA BAY based on:
LENGTH OF SERIES: 1 YEAR
TIME PERIOD: January 1986 - December 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:
HIGHEST OBSERVED WATER LEVEL (10/24/1986) = 0.449
MEAN HIGHER HIGH WATER MHHW = 0.305
MEAN HIGH WATER MHW = 0.305
MEAN SEA LEVEL MSL = 0.158
MEAN TIDE LEVEL MTL = 0.157
MEAN LOW WATER MLW = 0.009
MEAN LOWER LOW WATER MLLW = 0.000
LOWEST OBSERVED WATER LEVEL (01/27/1986) = -0.706
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
1679 A 1985 0.504 0.199
1679 B 1985 0.315 0.010
1679 C 1985 0.521 0.216
1679 D 1985 0.592 0.287
1679 E 1985 0.568 0.263
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 7 of 7
Station ID: 8761679 PUBLICATION DATE: 04/16/2018
Name: ST. MARYS POINT, BARATARIA BAY
LA
NOAA Chart: 11358 Latitude: 29° 25.9' N ( 29.43170)
USGS Quad: WILKINSON BAY Longitude: 89° 56.3' W ( -89.93830)
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.