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Bench Mark Sheet for 8676329, MACKAY RIVER, ICWW, BUTTERMILK SOUND GA

Superseded Epoch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Small blue map location marker Unpublished bench mark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: 8676329                         PUBLICATION DATE:  03/09/2004
Name:       MACKAY RIVER, ICWW, BUTTERMILK SOUND              
            GA
NOAA Chart: 11508                           Latitude:   31° 17.1' N (  31.28500)
USGS Quad:  BRUNSWICK EAST                  Longitude:  81° 23.1' W ( -81.38500)


To reach the tidal bench marks, proceed by boat to the marshy area on the east
shore of Mackay River on Little St. Simons Island, 1.6 km (1.0 mi) north of the
intersection with Hampton River and Wilson Creek.  The bench marks are situated
between two small hammocks immediately adjacent to Day Mark 221, 32 m (105 ft)
south of northern hammock and 15.24 m (50.0 ft) north of southern hammock.  The
tide gage and staff were located on Day Mark 221 on the Intracoastal Waterway.


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


                 PRIMARY BENCH MARK STAMPING:  6329 A 1980
                         DESIGNATION:          867 6329 A TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         4904
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Unspecified deep rod                  OPUS PID:        
LATITUDE:   31° 17.6' N (  31.29330)          LONGITUDE:  81° 23.7' W ( -81.39500)


The primary bench mark is a disk located in a marshy area on the east shore of
Mackay River situated between two small hammocks immediately adjacent to Day
Mark 221, 21 m (69 ft) east of the shoreline.  The bench mark is crimped to the
top of a deep rod driven 18.3 m (60 ft) to refusal and encased in a 1.16 m (3.8
ft) piece of white 4-inch PVC pipe which protrudes 0.37 m (1.2 ft) above ground.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  5

                                                                                
Station ID: 8676329                         PUBLICATION DATE:  03/09/2004
Name:       MACKAY RIVER, ICWW, BUTTERMILK SOUND              
            GA
NOAA Chart: 11508                           Latitude:   31° 17.1' N (  31.28500)
USGS Quad:  BRUNSWICK EAST                  Longitude:  81° 23.1' W ( -81.38500)


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


                         BENCH MARK STAMPING:  6329 B 1980
                         DESIGNATION:          867 6329 B TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         4905
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Unspecified deep rod                  OPUS PID:        
LATITUDE:   31° 17.6' N (  31.29330)          LONGITUDE:  81° 23.7' W ( -81.39500)


The bench mark is a disk located in a marshy area on the east shore of Mackay
River situated between two hammocks, immediately adjacent to Day Mark 221, 45 m
(148 ft) east of the shoreline, 24 m (79 ft) NE of bench mark 6329 A 1980, 22.56
m (74.0 ft) south of northern hammock, and 12.50 m (41.0 ft) north of southern
hammock.  The bench mark is crimped to the top of a deep rod driven 18.3 m (60
ft) to refusal and encased in a 1.22 m (4.0 ft) piece of white 4-inch PVC pipe
in length which protrudes 0.40 m (1.3 ft) above ground.



                         BENCH MARK STAMPING:  6329 C 1980
                         DESIGNATION:          867 6329 C TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         4906
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Unspecified deep rod                  OPUS PID:        
LATITUDE:   31° 17.6' N (  31.29330)          LONGITUDE:  81° 23.7' W ( -81.39500)


The bench mark is a disk located in a marshy area on the east shore of Mackay
River situated between two small hammocks immediately adjacent to Day Mark 221,
77 m (252 ft) east of the shoreline, 31.70 m (104.0 ft) NE of bench mark 6329 B
1980, 15.24 m (50.0 ft) north of southern hammock and 15.24 m (50.0 ft) south of
northern hammock.  The bench mark is crimped to the top of a deep rod driven
18.3 m (60 ft) to refusal and encased in a 1.13 m (3.7 ft) piece of white 4-inch
PVC pipe which protrudes 0.40 m (1.3 ft) above ground.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  5

                                                                                
Station ID: 8676329                         PUBLICATION DATE:  03/09/2004
Name:       MACKAY RIVER, ICWW, BUTTERMILK SOUND              
            GA
NOAA Chart: 11508                           Latitude:   31° 17.1' N (  31.28500)
USGS Quad:  BRUNSWICK EAST                  Longitude:  81° 23.1' W ( -81.38500)


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


                         BENCH MARK STAMPING:  6329 D 1980
                         DESIGNATION:          867 6329 D TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         4907
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Unspecified deep rod                  OPUS PID:        
LATITUDE:   31° 17.6' N (  31.29330)          LONGITUDE:  81° 23.7' W ( -81.39500)


The bench mark is a disk located in a marshy area on the east shore of Mackay
River situated between two small hammocks immediately adjacent to Day Mark 221,
101.80 m (334.0 ft) east of the shoreline, 33.53 m (110.0 ft) south of northern
hammock and 21.34 m (70.0 ft) north of southern hammock.  The bench mark is set
atop a deep rod driven to refusal at 18.3 m (60 ft) and encased in a 1.16 m (3.8
ft) piece of 4-inch white PVC pipe which protrudes 0.37 m (1.2 ft) above ground.



                         BENCH MARK STAMPING:  6329 E 1980
                         DESIGNATION:          867 6329 E TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         4908
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Unspecified deep rod                  OPUS PID:        
LATITUDE:   31° 17.6' N (  31.29330)          LONGITUDE:  81° 23.7' W ( -81.39500)


The bench mark is a disk located in a marshy area on the east shore of Mackay
River situated between two small hammocks immediately adjacent to Day Mark 221,
142.65 m (468.0 ft) east of the shoreline, 39.62 m (130.0 ft) south of northern
hammock and 21.34 m (70.0 ft) north of southern hammock.  The bench mark is
crimped to the top of a deep rod driven 18.3 m (60 ft) to refusal and encased in
a 1.07 m (3.5 ft) piece of white 4-inch PVC pipe which protrudes 0.46 m (1.5 ft)
above ground.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  5

                                                                                
Station ID: 8676329                         PUBLICATION DATE:  03/09/2004
Name:       MACKAY RIVER, ICWW, BUTTERMILK SOUND              
            GA
NOAA Chart: 11508                           Latitude:   31° 17.1' N (  31.28500)
USGS Quad:  BRUNSWICK EAST                  Longitude:  81° 23.1' W ( -81.38500)


                            T I D A L   D A T U M S 


Tidal datums at MACKAY RIVER, ICWW, BUTTERMILK SOUND based on:

     LENGTH OF SERIES:      1 MONTH
     TIME PERIOD:           May 1980 - May 1980
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  8670870 FORT PULASKI, SAVANNAH RIVER


Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:

     MEAN HIGHER HIGH WATER                     MHHW   =  2.264
     MEAN HIGH WATER                            MHW    =  2.167
     MEAN SEA LEVEL                             MSL    =  1.199
     MEAN TIDE LEVEL                            MTL    =  1.120
     MEAN LOW WATER                             MLW    =  0.073
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     6329 A 1980                                 2.655    0.488
     6329 B 1980                                 2.746    0.579
     6329 C 1980                                 2.750    0.583
     6329 D 1980                                 2.675    0.508
     6329 E 1980                                 2.648    0.481


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

                                                                                
Station ID: 8676329                         PUBLICATION DATE:  03/09/2004
Name:       MACKAY RIVER, ICWW, BUTTERMILK SOUND              
            GA
NOAA Chart: 11508                           Latitude:   31° 17.1' N (  31.28500)
USGS Quad:  BRUNSWICK EAST                  Longitude:  81° 23.1' W ( -81.38500)


                             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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Products available at 8676329 MACKAY RIVER, ICWW, BUTTERMILK SOUND, GA

Revised: 08/08/2018
NOAA / National Ocean Service
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