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Bench Mark Sheet for 8720186, FORT GEORGE ISLAND FL

Superseded Epoch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Small blue map location marker Unpublished bench mark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  7

                                                                                
Station ID: 8720186                         PUBLICATION DATE:  11/20/2009
Name:       FORT GEORGE ISLAND                                
            FL
NOAA Chart: 11490                           Latitude:   30° 26.4' N (  30.44000)
USGS Quad:  MAYPORT                         Longitude:  81° 26.3' W ( -81.43830)


To reach the tidal bench marks from the intersection of State Highway A1A and
the Mayport Ferry proceed NE on State Highway A1A for 1.0 km (0.6 mi) to Fort
George Road, then north on Fort George Road for 0.8 km (0.5 mi) to Palmetto
Avenue, then north on Palmetto Avenue for 3.0 km (2.0 mi) to the Kingsley
Plantation, follow the western leading drive to the NW corner of the plantation
property.  The bench marks are located in the area around the Park Ranger
residence.  The tide gage and staff were located on a free-standing structure,
61.0 m (200.0 ft) NW of the NW corner of the largest white house on the
plantation, and 15.0 m (50.0 ft) north of the shoreline.  


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


                 PRIMARY BENCH MARK STAMPING:  0186 A 1978
                         DESIGNATION:          872 0186 A TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         5062
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  BC1395
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   30° 26.4' N (  30.44028)          LONGITUDE:  81° 26.3' W ( -81.43889)


The primary bench mark is a disk set in a round concrete monument, flush with
the ground, 40.0 m (130.0 ft) NW of the 2-story building referred to as the
Army-Navy Club, 14.9 m (49.0 ft) SSW of the NW corner and inline with the west
side of a wood bulkhead along the Fort George River, 14.3 m (47.0 ft) SSW of the
NW corner of a wooden sea wall, 7.9 m (26.0 ft) NE of a 91.4 cm (36.0 in) oak
tree, 5.0 m (16.5 ft) east of a 81.3 cm (32.0 in) oak tree, 0.3 m (1.0 ft) south
of the south edge of a walking path, 0.3 m (1.0 ft) south of the south edge of a
walking path and 0.2 m (0.5 ft) north of a carsonite witness post.  NOTE:  A
magnet was buried at the south side of the monument.  

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  7

                                                                                
Station ID: 8720186                         PUBLICATION DATE:  11/20/2009
Name:       FORT GEORGE ISLAND                                
            FL
NOAA Chart: 11490                           Latitude:   30° 26.4' N (  30.44000)
USGS Quad:  MAYPORT                         Longitude:  81° 26.3' W ( -81.43830)


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


                         BENCH MARK STAMPING:  FT GEORGE NO 1 RESET 1977
                         DESIGNATION:          FT GEORGE 1 RESET

MONUMENTATION:           Vertical Control disk                 VM#:         5059
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  BC1394
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   30° 26.4' N (  30.43972)          LONGITUDE:  81° 26.2' W ( -81.43722)


The bench mark is a disk set in the top of a round concrete monument flush with
the ground, 59.9 m (196.5 ft) NE of the center of a brick and concrete cistern,
56.1 m (184.0 ft) east of the center of the easternmost wall of the Kingsley
house, 23.9 m (78.5 ft) NNE of bench mark FT. GEORGE NO 2 RESET 1977, 7.0 m
(23.0 ft) south of the top of the bank of the Ft. George River, and 6.1 m (20.0
ft) SE of a 61.0 cm (24.0 in) cypress tree.  NOTE:  A magnet was buried at the
south side of the monument.  

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  7

                                                                                
Station ID: 8720186                         PUBLICATION DATE:  11/20/2009
Name:       FORT GEORGE ISLAND                                
            FL
NOAA Chart: 11490                           Latitude:   30° 26.4' N (  30.44000)
USGS Quad:  MAYPORT                         Longitude:  81° 26.3' W ( -81.43830)


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


                         BENCH MARK STAMPING:  FT GEORGE NO 2 RESET 1977
                         DESIGNATION:          FT GEORGE 2 RESET

MONUMENTATION:           Vertical Control disk                 VM#:         5060
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  BC1393
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   30° 26.4' N (  30.43944)          LONGITUDE:  81° 26.2' W ( -81.43722)


The bench mark is a disk set in the top of a round concrete monument flush with
the ground, 57.6 m (188.9 ft) ESE of the center of the easternmost wall of the
Kingsley house, 46.4 m (152.3 ft) ENE of the center of a brick and concrete
cistern, 23.9 m (78.5 ft) SSW of bench mark FT GEORGE NO 1 RESET 1977, and 16.5
m (54.2 ft) NNE of bench mark FT GEORGE NO 3 RESET 1977, and 9.9 m (32.5 ft)
east of the east side of a 91.4 cm (36.0 in) hickory tree.  NOTES:  The mark can
be located with a metal detector.   A magnet was buried at the south side of the
monument.  

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  7

                                                                                
Station ID: 8720186                         PUBLICATION DATE:  11/20/2009
Name:       FORT GEORGE ISLAND                                
            FL
NOAA Chart: 11490                           Latitude:   30° 26.4' N (  30.44000)
USGS Quad:  MAYPORT                         Longitude:  81° 26.3' W ( -81.43830)


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


                         BENCH MARK STAMPING:  FT GEORGE NO 3 RESET 1977
                         DESIGNATION:          FT GEORGE 3 RESET

MONUMENTATION:           Vertical Control disk                 VM#:         5061
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  BC1392
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   30° 26.4' N (  30.43944)          LONGITUDE:  81° 26.2' W ( -81.43722)


The bench mark is a disk set in the top of a round concrete monument and flush
with the ground, 45.0 m (147.0 ft) east of the center of a brick and concrete
cistern, 37.3 m (122.4 ft) NE of the NE corner of the stable and carriage house,
63.3 m (214.4 ft) SE of the easternmost wall of the Kingsley house, 16.5 m (54.2
ft) south of bench mark FT GEORGE NO 2 RESET 1977, and 1.3 m (4.1 ft) west of a
carsonite witness post.  NOTE:  A magnet was buried on the south side of the
monument.  



                         BENCH MARK STAMPING:  0186 E 1978
                         DESIGNATION:          872 0186 E TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         5063
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  BC1391
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   30° 26.2' N (  30.43667)          LONGITUDE:  81° 26.3' W ( -81.43889)


The bench mark is a disk set in a concrete monument, level with the ground, 88.0
m (290.0 ft) west of the centerline of the gravel drive to Kingsley Plantation,
5.0 m (18.0 ft) SW of the SW corner of the seventh (last) slave quarter west of
Palmetto Road, 9.8 m (32.2 ft) WNW of the SE corner of the slave quarter, 1.5 m
(5.0 ft) SW of a 38.1 cm (15.0 in) oak tree marked with an "X", 1.8 m (6.0 ft)
above ground level, 1.8 m (6.0 ft) north of a carsonite witness post and 1.6 m
(5.1 ft) north of a 35.6 cm (14.0 in) palmetto palm.  NOTE:  A magnet was buried
at the south side of the monument.  

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  5 of  7

                                                                                
Station ID: 8720186                         PUBLICATION DATE:  11/20/2009
Name:       FORT GEORGE ISLAND                                
            FL
NOAA Chart: 11490                           Latitude:   30° 26.4' N (  30.44000)
USGS Quad:  MAYPORT                         Longitude:  81° 26.3' W ( -81.43830)


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


                         BENCH MARK STAMPING:  Q 324 1970
                         DESIGNATION:          Q 324

MONUMENTATION:           Bench Mark disk                       VM#:        19266
AGENCY:                  US Coast and Geodetic Survey (USC &
                         GS)                                       IDB PID#:  BC0442
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   30° 25.5' N (  30.42417)          LONGITUDE:  81° 26.0' W ( -81.43353)


The bench mark is a disk set in the top of a concrete post projecting 5.1 cm
(2.0 in) above the level of the ground on the grounds of Kingsley Plantation on
Fort George Island, about 1.8 km (1.1 mi) south of the north end of the island,
5.8 m (19.0 ft) east of the center line of the avenue, 11.0 m (36.0 ft) south of
a power line pole with two transformers, 0.5 m (1.5 ft) east of the ground end
of a guy wire, 0.5 m (1.5 ft) north of a metal witness post, and 0.3 m (1.0 ft)
above the level of Palmetto Avenue.    

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  6 of  7

                                                                                
Station ID: 8720186                         PUBLICATION DATE:  11/20/2009
Name:       FORT GEORGE ISLAND                                
            FL
NOAA Chart: 11490                           Latitude:   30° 26.4' N (  30.44000)
USGS Quad:  MAYPORT                         Longitude:  81° 26.3' W ( -81.43830)


                            T I D A L   D A T U M S 


Tidal datums at FORT GEORGE ISLAND based on:

     LENGTH OF SERIES:      6 MONTHS
     TIME PERIOD:           April 1978 - September 1978
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  8720220 MAYPORT (FERRY DEPOT), SAINT JOHNS RIVER


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

     MEAN HIGHER HIGH WATER                     MHHW   =  1.591
     MEAN HIGH WATER                            MHW    =  1.500
     North American Vertical Datum              NAVD88 =  0.906
     MEAN SEA LEVEL                             MSL    =  0.799
     MEAN TIDE LEVEL                            MTL    =  0.772
     MEAN LOW WATER                             MLW    =  0.043
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     0186 A 1978                                 3.413    1.913
     FT GEORGE NO 1 RESET 1977                   3.758    2.258
     FT GEORGE NO 2 RESET 1977                   3.871    2.371
     FT GEORGE NO 3 RESET 1977                   3.978    2.478
     0186 E 1978                                 3.057    1.557
     Q 324 1970                                  5.148    3.648


Foot Notes:

Geodetic heights of the bench marks meet all NOAA/NOS/NGS quality control
standards for Second Order, Class 1 leveling.  It is advised that a confirmation
set of levels be established for bench mark Q 324 1970 to verify height
differences before using tidal bench mark elevation information.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  7 of  7

                                                                                
Station ID: 8720186                         PUBLICATION DATE:  11/20/2009
Name:       FORT GEORGE ISLAND                                
            FL
NOAA Chart: 11490                           Latitude:   30° 26.4' N (  30.44000)
USGS Quad:  MAYPORT                         Longitude:  81° 26.3' W ( -81.43830)


                             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 8720186 FORT GEORGE ISLAND, FL

Revised: 08/08/2018
NOAA / National Ocean Service
Web site owner: Center for Operational Oceanographic Products and Services