U.S. DEPARTMENT OF COMMERCE
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National Ocean Service
Datums Page Page 1 of 5
Station ID: 8761108 PUBLICATION DATE: 05/07/2003
Name: BAY GARDENE
LA
NOAA Chart: 11364 Latitude: 29° 35.9' N ( 29.59830)
USGS Quad: BLACK BAY SOUTH Longitude: 89° 37.1' W ( -89.61830)
To reach the tidal bench marks from the Pointe A La Hache Boat Basin, proceed by
boat a short distance NE to Back Levee Canal, then SE on Back Levee Canal for 8
km (5 mi) to a spillway canal on the left, then east and NE along the spillway
canal and bayous, past Clam Bay and out into Bay Law, then ENE across American
Bay for 5.6 km (3.5 mi) to Triple Pass, and then NE across Bay Gardene for 3 km
(2 mi) to the Louisiana Wildlife and Fisheries Bay Gardene Camp. The bench
marks are located near the camp and in the marsh to the west. The tide gage and
staff were located at the NW corner of the camp's main dock and on the bulkhead,
respectively.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 1108 A 1980
DESIGNATION: 876 1108 A
MONUMENTATION: Tidal Station disk VM#: 7130
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 29° 35.9' N ( 29.59830) LONGITUDE: 89° 37.1' W ( -89.61830)
The primary bench mark is a disk located under the Louisiana Wildlife and
Fisheries Bay Gardene Camp building which is on piles, 28.35 m (93.0 ft) west of
the wood bulkhead along the east side of the camp, 11.58 m (38.0 ft) south of
the wood bulkhead along the north side of the camp, and 1.52 m (5.0 ft) SE of
the NW corner of the camp building. The bench mark is crimped to a stainless
steel rod driven 19.5 m (64 ft) to substantial resistance, and encased in a
4-inch PVC pipe and concrete kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 8761108 PUBLICATION DATE: 05/07/2003
Name: BAY GARDENE
LA
NOAA Chart: 11364 Latitude: 29° 35.9' N ( 29.59830)
USGS Quad: BLACK BAY SOUTH Longitude: 89° 37.1' W ( -89.61830)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1108 C 1980
DESIGNATION: 876 1108 C
MONUMENTATION: Tidal Station disk VM#: 7131
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 29° 35.9' N ( 29.59830) LONGITUDE: 89° 37.1' W ( -89.61830)
The bench mark is a disk located west of the camp building, 57.3 m (188 ft) NW
of the NW corner of the generator building, 57.3 m (188 ft) north of the south
shore of the island, 17 m (56 ft) east of the southernmost dolphin in the old
boat slip, 10.36 m (34.0 ft) south of the north shore of the island, 6.4 m (21
ft) north of the north shore of a small freshwater pond, and 2.13 m (7.0 ft)
west of a wood sluiceway. The bench mark is set 0.06 m (0.2 ft) below ground
level, crimped to a stainless steel rod driven 19.5 m (64 ft) to substantial
resistance, and encased in a 4-inch PVC pipe and concrete kickblock.
BENCH MARK STAMPING: 1108 D 1980
DESIGNATION: 876 1108 D
MONUMENTATION: Tidal Station disk VM#: 7132
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 29° 35.9' N ( 29.59830) LONGITUDE: 89° 37.1' W ( -89.61830)
The bench mark is a disk located 48.16 m (158.0 ft) south of the south shore of
Lost Bayou, 36 m (118 ft) west of the west shore of a small freshwater pond on
the west side of the camp, 14 m (46 ft) north of the south shore of the island,
and 6.4 m (21 ft) SW of the SW corner of the old boat slip. The bench mark is
set 0.21 m (0.7 ft) above ground level, crimped to a stainless steel rod driven
19.5 m (64 ft) to substantial resistance, and encased in a 4-inch PVC pipe, and
concrete kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 8761108 PUBLICATION DATE: 05/07/2003
Name: BAY GARDENE
LA
NOAA Chart: 11364 Latitude: 29° 35.9' N ( 29.59830)
USGS Quad: BLACK BAY SOUTH Longitude: 89° 37.1' W ( -89.61830)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1108 E 1981
DESIGNATION: 876 1108 E
MONUMENTATION: Tidal Station disk VM#: 7133
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 29° 35.9' N ( 29.59830) LONGITUDE: 89° 37.1' W ( -89.61830)
The bench mark is a disk located in the SE corner of the camp grounds, 54.86 m
(180.0 ft) SSW of the NE corner of the main dock, 23.77 m (78.0 ft) SE of the SE
corner of the camp house, 10.36 m (34.0 ft) NW of the SE corner of the wood
bulkhead around the camp, and 5.49 m (18.0 ft) north of the wood bulkhead on the
south side of the camp. The bench mark is crimped to a stainless steel rod
driven 19.5 m (64 ft) to substantial resistance, and encased in a 4-inch PVC
pipe and concrete kickblock.
BENCH MARK STAMPING: 1108 F 1983
DESIGNATION: 876 1108 F
MONUMENTATION: Tidal Station disk VM#: 7134
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 29° 35.9' N ( 29.59830) LONGITUDE: 89° 37.1' W ( -89.61830)
The bench mark is a disk located 82 m (270 ft) NNW of Bench Mark 1108 D 1980, 50
m (164 ft) NE of the west shoreline of the island, and 16.76 m (55.0 ft) SSW of
the west shoreline of Lost Bayou. The bench mark is set 0.12 m (0.4 ft) above
ground level, crimped to a stainless steel rod driven 23.2 m (76 ft) to
substantial resistance, and encased in a 4-inch PVC pipe.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 8761108 PUBLICATION DATE: 05/07/2003
Name: BAY GARDENE
LA
NOAA Chart: 11364 Latitude: 29° 35.9' N ( 29.59830)
USGS Quad: BLACK BAY SOUTH Longitude: 89° 37.1' W ( -89.61830)
T I D A L D A T U M S
Tidal datums at BAY GARDENE based on:
LENGTH OF SERIES: 7 YEARS
TIME PERIOD: January 1981 - December 1987
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8747437 BAY WAVELAND YC, BAY ST. LOUIS
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
HIGHEST OBSERVED WATER LEVEL (10/27/1985) = 2.183
MEAN HIGHER HIGH WATER MHHW = 0.439
MEAN HIGH WATER MHW = 0.424
MEAN SEA LEVEL MSL = 0.227
MEAN TIDE LEVEL MTL = 0.221
MEAN LOW WATER MLW = 0.017
MEAN LOWER LOW WATER MLLW = 0.000
LOWEST OBSERVED WATER LEVEL (02/28/1984) = -1.167
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
1108 A 1980 0.875 0.451
1108 C 1980 1.126 0.702
1108 D 1980 0.493 0.069
1108 E 1981 0.759 0.335
1108 F 1983 0.588 0.164
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 8761108 PUBLICATION DATE: 05/07/2003
Name: BAY GARDENE
LA
NOAA Chart: 11364 Latitude: 29° 35.9' N ( 29.59830)
USGS Quad: BLACK BAY SOUTH Longitude: 89° 37.1' W ( -89.61830)
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.