Bench Mark Sheet for 8761819, TEXACO DOCK, HACKBERRY BAY LA

Superseded Epoch

Large map location marker Station Location
Small red map location marker Published bench mark
Small blue map location marker Unpublished bench mark

Bench mark positions only appear on the map if their coordinates in the CO-OPS database are at the precision of degrees/minutes/seconds/and tenths of seconds. If the coordinates are less precise, the mark will not appear.

Printable version

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  6

                                                                                
Station ID: 8761819                         PUBLICATION DATE:  04/27/2018
Name:       TEXACO DOCK, HACKBERRY BAY                        
            LA
NOAA Chart: 11358                           Latitude:   29° 24.1' N (  29.40170)
USGS Quad:  BAY DOSGRIS                     Longitude:  90°  2.3' W ( -90.03830)


To reach the tidal bench marks from Rigaud Marina at the east end of Grand Isle,
proceed by boat north on Barataria Bay Waterway to Channel Marker #34, then turn
left between islands and follow the channel NW for about 4.8 km (3.0 mi) to the
Texaco office at Bay De Chene Oil Field in Hackberry Bay.  The bench marks are
north of the living quarters.  The tide gage and staff were SW of the living
quarters at the end of the wharf on the east side of the slip.


                         T I D A L   B E N C H   M A R K S


                 PRIMARY BENCH MARK STAMPING:  1819 A 1986
                         DESIGNATION:          876 1819 A TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         7199
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Stainless steel rod                   OPUS PID#: BBBX73
LATITUDE:   29° 24.1' N (  29.40170)          LONGITUDE:  90°  2.2' W ( -90.03670)


The primary bench mark is a disk located between the living quarters and kitchen
buildings, 10.82 m (35.5 ft) SE of a utility pole along the walkway between the
kitchen and a small galvanized tank on piles, 10.67 m (35.0 ft) north of a
utility pole NW of a small white building on piles between the kitchen and
living quarters, 8.87 m (29.1 ft) east of the SE corner pile supporting a
galvanized tank SW of the kitchen facilities, 6.55 m (21.5 ft) east of the NE
pile supporting the wastewater treatment tank, and 0.37 m (1.2 ft) from a
witness post.  The bench mark is set 0.46 m (1.5 ft) above marsh level, crimped
to the top of a stainless steel rod driven 25.6 m (84 ft) to refusal, and
encased in a 5-inch PVC pipe driven 0.37 m (4.0 ft) into the marsh and extending
0.61 m (2.0 ft) above the marsh.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  6

                                                                                
Station ID: 8761819                         PUBLICATION DATE:  04/27/2018
Name:       TEXACO DOCK, HACKBERRY BAY                        
            LA
NOAA Chart: 11358                           Latitude:   29° 24.1' N (  29.40170)
USGS Quad:  BAY DOSGRIS                     Longitude:  90°  2.3' W ( -90.03830)


                         T I D A L   B E N C H   M A R K S


                         BENCH MARK STAMPING:  1819 B 1986
                         DESIGNATION:          876 1819 B TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         7200
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Stainless steel rod                   OPUS PID:        
LATITUDE:   29° 24.1' N (  29.40170)          LONGITUDE:  90°  2.2' W ( -90.03670)


The bench mark is a disk located 41 m (136 ft) NE of bench mark 1819 A 1986,
24.26 m (79.6 ft) SSE of a utility pole NE of the generator platform, 19.81 m
(65.0 ft) SE of the south corner pile supporting the generator platform, 7.38 m
(24.2 ft) NE of the second west support pile SE of the junction of the walkway
leading from the kitchen intersecting with the walkway leading to the amphibious
plane landing ramp, and 0.37 m (1.2 ft) south of a witness post.  The bench mark
is set 0.46 m (1.5 ft) above marsh level, crimped to the top of a stainless
steel rod driven 29.3 m (96 ft) to refusal, and encased in a 5-inch PVC pipe
driven 1.22 m (4.0 ft) into the marsh and extending 0.61 m (2.0 ft) above the
marsh.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  6

                                                                                
Station ID: 8761819                         PUBLICATION DATE:  04/27/2018
Name:       TEXACO DOCK, HACKBERRY BAY                        
            LA
NOAA Chart: 11358                           Latitude:   29° 24.1' N (  29.40170)
USGS Quad:  BAY DOSGRIS                     Longitude:  90°  2.3' W ( -90.03830)


                         T I D A L   B E N C H   M A R K S


                         BENCH MARK STAMPING:  1819 C 1986
                         DESIGNATION:          876 1819 C TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         7201
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Stainless steel rod                   OPUS PID:        
LATITUDE:   29° 24.1' N (  29.40170)          LONGITUDE:  90°  2.2' W ( -90.03670)


The bench mark is a disk located 73 m (240 ft) NE of bench mark 1819 B 1986,
17.31 m (56.8 ft) NW of the approximate SE shoreline, 11.89 m (39.0 ft) SE of
the approximate NW shoreline, and 0.40 m (1.3 ft) SE of a witness post.  The
bench mark is set 0.46 m (1.5 ft) above marsh level, crimped to the top of a
stainless steel rod driven 30.5 m (100 ft) to refusal, and encased in a 5-inch
PVC pipe driven 1.22 m (4.0 ft) into the marsh and extending 0.61 m (2.0 ft)
above the marsh.



                         BENCH MARK STAMPING:  1819 D 1986
                         DESIGNATION:          876 1819 D TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         7202
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Stainless steel rod                   OPUS PID:        
LATITUDE:   29° 24.1' N (  29.40170)          LONGITUDE:  90°  2.2' W ( -90.03670)


The bench mark is a disk located 30.48 m (100.0 ft) NE of bench mark 1819 C
1986, 25.15 m (82.5 ft) south of a small shell reef along the north shoreline,
12.07 m (39.6 ft) NW of the approximate SE shoreline in line with a small
platform in the bay, and 0.43 m (1.4 ft) SE of a witness post.  The bench mark
is set 0.46 m (1.5 ft) above marsh level, crimped to the top of a stainless
steel rod driven 24.4 m (80 ft) to substantial resistance, and encased in a
5-inch PVC pipe driven 1.22 m (4.0 ft) into the marsh and extending 0.61 m (2.0
ft) above the marsh.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  6

                                                                                
Station ID: 8761819                         PUBLICATION DATE:  04/27/2018
Name:       TEXACO DOCK, HACKBERRY BAY                        
            LA
NOAA Chart: 11358                           Latitude:   29° 24.1' N (  29.40170)
USGS Quad:  BAY DOSGRIS                     Longitude:  90°  2.3' W ( -90.03830)


                         T I D A L   B E N C H   M A R K S


                         BENCH MARK STAMPING:  1819 E 1986
                         DESIGNATION:          876 1819 E TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         7203
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Stainless steel rod                   OPUS PID:        
LATITUDE:   29° 24.1' N (  29.40170)          LONGITUDE:  90°  2.2' W ( -90.03670)


The bench mark is a disk located 30 m (100 ft) NE of bench mark 1819 D 1986,
24.08 m (79.0 ft) west of a pond at the islands east end, 12.65 m (41.5 ft) NW
of   the approximate SE shoreline, 10 m (33 ft) SE of the approximate NW
shoreline, and 0.37 m (1.2 ft) south of a witness post.  The bench mark is set
0.46 m (1.5 ft) above marsh level, crimped to the top of a stainless steel rod
driven 28.0 m (92 ft) to refusal, and encased in a 5-inch PVC pipe driven 1.22 m
(4.0 ft) into the marsh and extending 0.61 m (2.0 ft) above the marsh.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  5 of  6

                                                                                
Station ID: 8761819                         PUBLICATION DATE:  04/27/2018
Name:       TEXACO DOCK, HACKBERRY BAY                        
            LA
NOAA Chart: 11358                           Latitude:   29° 24.1' N (  29.40170)
USGS Quad:  BAY DOSGRIS                     Longitude:  90°  2.3' W ( -90.03830)


                            T I D A L   D A T U M S 


Tidal datums at TEXACO DOCK, HACKBERRY BAY based on:

     LENGTH OF SERIES:      11 MONTHS
     TIME PERIOD:           November 1986 - September 1987
     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   =  0.275
     MEAN HIGH WATER                            MHW    =  0.273
     MEAN SEA LEVEL                             MSL    =  0.141
     MEAN TIDE LEVEL                            MTL    =  0.138
     MEAN LOW WATER                             MLW    =  0.002
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     1819 A 1986                                 0.542    0.269
     1819 B 1986                                 0.507    0.234
     1819 C 1986                                 0.483    0.210
     1819 D 1986                                 0.455    0.182
     1819 E 1986                                 0.455    0.182


                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  6 of  6

                                                                                
Station ID: 8761819                         PUBLICATION DATE:  04/27/2018
Name:       TEXACO DOCK, HACKBERRY BAY                        
            LA
NOAA Chart: 11358                           Latitude:   29° 24.1' N (  29.40170)
USGS Quad:  BAY DOSGRIS                     Longitude:  90°  2.3' W ( -90.03830)


                             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.

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