Bench Mark Sheet for 8760668, GRAND PASS 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Superseded Epoch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Small blue map location marker Unpublished bench mark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  5

                                                                                
Station ID: 8760668                         PUBLICATION DATE:  05/16/2003
Name:       GRAND PASS                                        
            LA
NOAA Chart: 11371                           Latitude:   30°  7.6' N (  30.12670)
USGS Quad:  AU PITRE                        Longitude:  89° 13.3' W ( -89.22170)


To reach the tidal bench marks from the Pass Christian Marina, proceed by boat
SSE across Mississippi Sound for 20 km (11 nm) to Little Bayou Pierre, just east
of Grand Pass, continue south on Little Bayou Pierre to the Louisiana Wildlife
and Fisheries Camp.  The bench marks are located in the vicinity of the camp and
on the east side of a slough that surrounds the camp on the east and north
sides.  The tide gage and staff were located under the elevated walkway north of
the stairs leading up to the camp.


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


                 PRIMARY BENCH MARK STAMPING:  0668 A 1980
                         DESIGNATION:          876 0668 A

MONUMENTATION:           Tidal Station disk                    VM#:         7095
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Stainless steel rod                   OPUS PID:        
LATITUDE:   30°  7.6' N (  30.12670)          LONGITUDE:  89° 13.3' W ( -89.22170)


The primary bench mark is a disk located on the east shore of the slough around
the wildlife camp, SE of the SE corner of the camp building, 66 m (218 ft) east
of the SW point of land at the southern mouth of the slough around the camp,
21.34 m (70.0 ft) NE of the NW corner of a dead-end slough, 10.36 m (34.0 ft) NE
of the NE corner of a dead-end slough, and 9.14 m (30.0 ft) south of the south
shoreline of the slough around the camp.  The bench mark is set 0.12 m (0.4 ft)
below ground level, crimped to the top of a stainless steel rod driven 18.3 m
(60 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: 8760668                         PUBLICATION DATE:  05/16/2003
Name:       GRAND PASS                                        
            LA
NOAA Chart: 11371                           Latitude:   30°  7.6' N (  30.12670)
USGS Quad:  AU PITRE                        Longitude:  89° 13.3' W ( -89.22170)


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


                         BENCH MARK STAMPING:  0668 B 1980
                         DESIGNATION:          876 0668 B

MONUMENTATION:           Tidal Station disk                    VM#:         7096
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Stainless steel rod                   OPUS PID:        
LATITUDE:   30°  7.6' N (  30.12670)          LONGITUDE:  89° 13.3' W ( -89.22170)


The bench mark is a disk located on the east shore of the slough around the
wildlife camp, due east of the north point of the island on which the camp is
located, 143 m (468 ft) NNE of bench mark 0668 A 1980, 8 m (26 ft) east of the
east shoreline of the slough, 5.49 m (18.0 ft) WNW of the SW end of a dead-end
slough, and 0.27 m (0.9 ft) west of a witness post.  The bench mark is set 0.15
m (0.5 ft) below ground level, crimped to the top of a stainless steel rod
driven 16.8 m (55 ft) to substantial resistance, and encased in a 4-inch PVC
pipe and concrete kickblock.



                         BENCH MARK STAMPING:  0668 C 1980
                         DESIGNATION:          876 0668 C

MONUMENTATION:           Tidal Station disk                    VM#:         7097
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Stainless steel rod                   OPUS PID:        
LATITUDE:   30°  7.6' N (  30.12670)          LONGITUDE:  89° 13.3' W ( -89.22170)


The bench mark is a disk located on the east shore of Little Bayou Pierre, 69 m
(225 ft) NNW of bench mark 0668 B 1980, 14.63 m (48.0 ft) SSE of a 0.15 m (0.5
ft) creosote piling, 8.84 m (29.0 ft) east of the east shoreline of Little Bayou
Pierre, and 0.24 m (0.8 ft) west of a witness post.  The bench mark is set 0.09
m (0.3 ft) below ground level, crimped to the top of a stainless steel rod
driven 19.8 m (65 ft) to refusal, 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: 8760668                         PUBLICATION DATE:  05/16/2003
Name:       GRAND PASS                                        
            LA
NOAA Chart: 11371                           Latitude:   30°  7.6' N (  30.12670)
USGS Quad:  AU PITRE                        Longitude:  89° 13.3' W ( -89.22170)


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


                         BENCH MARK STAMPING:  0668 D 1983
                         DESIGNATION:          876 0668 D

MONUMENTATION:           Tidal Station disk                    VM#:         7098
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Stainless steel rod                   OPUS PID:        
LATITUDE:   30°  7.6' N (  30.12670)          LONGITUDE:  89° 13.3' W ( -89.22170)


The bench mark is a disk located 70 m (230 ft) SSE of bench mark 0668 B 1980, 25
m (82 ft) west of the west shore of a small saltwater pond, 7.32 m (24.0 ft)
east of the east shore of an unnamed bayou west of the wildlife camp, and 0.34 m
(1.1 ft) SW of a witness post.  The bench mark is set 0.09 m (0.3 ft) above
ground level, crimped to the top of a stainless steel rod driven 18.3 m (60 ft)
to substantial resistance, and encased in a 4-inch PVC pipe and concrete
kickblock.



                         BENCH MARK STAMPING:  0668 E 1983
                         DESIGNATION:          876 0668 E

MONUMENTATION:           Tidal Station disk                    VM#:         7099
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Stainless steel rod                   OPUS PID:        
LATITUDE:   30°  7.6' N (  30.12670)          LONGITUDE:  89° 13.3' W ( -89.22170)


The bench mark is a disk located near the front entrance to the wildlife camp,
8.53 m (28.0 ft) north of a wooden bulkhead south of the camp, 8.23 m (27.0 ft)
east of a wooden bulkhead west of the camp, 5.49 m (18.0 ft) SW of the SW corner
of the camp building, 1.52 m (5.0 ft) NNW of a 30.48 m (100.0 ft) radio tower,
and 0.37 m (1.2 ft) north of a witness post.  The bench mark is set 0.06 m (0.2
ft) below ground level, crimped to the top of a stainless steel rod driven 23.2
m (76 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  4 of  5

                                                                                
Station ID: 8760668                         PUBLICATION DATE:  05/16/2003
Name:       GRAND PASS                                        
            LA
NOAA Chart: 11371                           Latitude:   30°  7.6' N (  30.12670)
USGS Quad:  AU PITRE                        Longitude:  89° 13.3' W ( -89.22170)


                            T I D A L   D A T U M S 


Tidal datums at GRAND PASS based on:

     LENGTH OF SERIES:      84 MONTHS
     TIME PERIOD:           October 1981 - September 1988
     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 (01/20/1983)         =  1.697
     MEAN HIGHER HIGH WATER                     MHHW   =  0.447
     MEAN HIGH WATER                            MHW    =  0.430
     MEAN TIDE LEVEL                            MTL    =  0.223
     MEAN SEA LEVEL                             MSL    =  0.221
     MEAN LOW WATER                             MLW    =  0.017
     MEAN LOWER LOW WATER                       MLLW   =  0.000
     LOWEST  OBSERVED WATER LEVEL (04/12/1988)         = -0.680

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     0668 A 1980                                 0.767    0.337
     0668 B 1980                                 0.619    0.189
     0668 C 1980                                 0.661    0.231
     0668 D 1983                                 0.873    0.443
     0668 E 1983                                 0.801    0.371


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

                                                                                
Station ID: 8760668                         PUBLICATION DATE:  05/16/2003
Name:       GRAND PASS                                        
            LA
NOAA Chart: 11371                           Latitude:   30°  7.6' N (  30.12670)
USGS Quad:  AU PITRE                        Longitude:  89° 13.3' W ( -89.22170)


                             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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