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Bench Mark Sheet for 8724264, BIG TORCH KEY, WEST SIDE 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Superseded Epoch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Small blue map location marker Unpublished bench mark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  6

                                                                                
Station ID: 8724264                         PUBLICATION DATE:  04/29/2004
Name:       BIG TORCH KEY, WEST SIDE                          
            FL
NOAA Chart: 11448                           Latitude:   24° 42.3' N (  24.70500)
USGS Quad:  SUMMERLAND KEY                  Longitude:  81° 26.0' W ( -81.43330)


To reach the tidal bench marks from Summerland Key Post Office, proceed east on
U.S. Highway 1 for 5.07 km (3.15 mi) to a paved road leading north on Middle
Torch Key, then turn left and proceed north and west on the paved road for 3.9
km (2.4 mi) to the junction of a paved road leading to Big Torch Key, then turn
and proceed west and north on the paved road for 3.7 km (2.3 mi) to the property
of Stanley Hoke.  The bench marks are located around a landfill and the paved
road.  The tide gage and staff were located offshore, west of the residence.


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


                 PRIMARY BENCH MARK STAMPING:  NO 1 1973
                         DESIGNATION:          872 4264 TIDAL 1

MONUMENTATION:           Tidal Station disk                    VM#:         6870
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  AA0720
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   24° 42.4' N (  24.70670)          LONGITUDE:  81° 26.0' W ( -81.43330)


The primary bench mark is a disk set flush in a concrete monument located at the
NW corner of the landfill west of the Hoke residence, 2.35 m (7.7 ft) east of
the west edge of the fill, 2.13 m (7.0 ft) south of the north edge of the fill,
and at ground level.

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

                                                                                
Station ID: 8724264                         PUBLICATION DATE:  04/29/2004
Name:       BIG TORCH KEY, WEST SIDE                          
            FL
NOAA Chart: 11448                           Latitude:   24° 42.3' N (  24.70500)
USGS Quad:  SUMMERLAND KEY                  Longitude:  81° 26.0' W ( -81.43330)


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


                         BENCH MARK STAMPING:  NO 2 1973
                         DESIGNATION:          872 4264 TIDAL 2

MONUMENTATION:           Tidal Station disk                    VM#:         6871
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  AA0719
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   24° 42.4' N (  24.70670)          LONGITUDE:  81° 26.0' W ( -81.43330)


The bench mark is a diskt located near the west edge of the landfill west of the
residence, 15.54 m (51.0 ft) south of the north edge of the fill, 13.50 m (44.3
ft) south of bench mark NO 1 1973, and 3.54 m (11.6 ft) east of the west edge of
the fill.  The mark is set 6 cm (0.2 ft) above ground level, crimped to the top
of a copper-clad steel rod, and is imbedded in a 0.30 m (0.98 ft) square
concrete monument.



                         BENCH MARK STAMPING:  NO 3 1973
                         DESIGNATION:          872 4264 TIDAL 3

MONUMENTATION:           Tidal Station disk                    VM#:         6872
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Mass of cement                        OPUS PID:        
LATITUDE:   24° 42.3' N (  24.70500)          LONGITUDE:  81° 26.0' W ( -81.43330)


The bench mark is a disk set in cement on the west side of the key, 4.66 m (15.3
ft) east of the west edge of filled land, 2.13 m (7.0 ft) north of a canal on
the south side of the filled land, and 9 cm (0.3 ft) above the land.

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

                                                                                
Station ID: 8724264                         PUBLICATION DATE:  04/29/2004
Name:       BIG TORCH KEY, WEST SIDE                          
            FL
NOAA Chart: 11448                           Latitude:   24° 42.3' N (  24.70500)
USGS Quad:  SUMMERLAND KEY                  Longitude:  81° 26.0' W ( -81.43330)


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


                         BENCH MARK STAMPING:  NO 4 1973
                         DESIGNATION:          872 4264 TIDAL 4

MONUMENTATION:           Tidal Station disk                    VM#:         6873
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  AA0718
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   24° 42.4' N (  24.70670)          LONGITUDE:  81° 26.0' W ( -81.43330)


The bench mark is a disk  located SW of the residence and north of a canal,
53.92 m (176.9 ft) east of the west end of the landfill, and 2.0 m (6.6 ft)
north of the canal on the south side of the fill.  The mark is set 6 cm (0.2 ft)
above ground level, crimped to the top of a copper-clad steel rod, and is
imbedded in a 0.30 m (0.98 ft) square concrete monument.



                         BENCH MARK STAMPING:  NO 5 1973
                         DESIGNATION:          872 4264 TIDAL 5

MONUMENTATION:           Tidal Station disk                    VM#:         6874
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  AA0717
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   24° 42.4' N (  24.70670)          LONGITUDE:  81° 25.9' W ( -81.43170)


The bench mark is a disk set flush in a concrete monument located SW of the
residence and north of the canal, 90 m (296 ft) east of the west edge of the
landfill, 36.27 m (119.0 ft) east of bench mark NO 4 1973, 9.30 m (30.5 ft)
south of the centerline of the Hoke driveway, 1.83 m (6.0 ft) north of the canal
bank, and at ground level.

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

                                                                                
Station ID: 8724264                         PUBLICATION DATE:  04/29/2004
Name:       BIG TORCH KEY, WEST SIDE                          
            FL
NOAA Chart: 11448                           Latitude:   24° 42.3' N (  24.70500)
USGS Quad:  SUMMERLAND KEY                  Longitude:  81° 26.0' W ( -81.43330)


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


                         BENCH MARK STAMPING:  4264 F 1982
                         DESIGNATION:          872 4264 F TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         6875
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  AA0716
SETTING CLASSIFICATION:  Rock outcrop                          OPUS PID:        
LATITUDE:   24° 42.4' N (  24.70670)          LONGITUDE:  81° 25.7' W ( -81.42830)


The bench mark is a disk located 0.2 km (0.1 mi) east of the entrance to the
Hoke property, 50.14 m (164.5 ft) WNW of utility pole #MTK5-95-53, 22.95 m (75.3
ft) NE of utility pole #MTK5-95-54, 10.82 m (35.5 ft) north of the centerline of
the paved road, and 1 m (3 ft) below road level.

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

                                                                                
Station ID: 8724264                         PUBLICATION DATE:  04/29/2004
Name:       BIG TORCH KEY, WEST SIDE                          
            FL
NOAA Chart: 11448                           Latitude:   24° 42.3' N (  24.70500)
USGS Quad:  SUMMERLAND KEY                  Longitude:  81° 26.0' W ( -81.43330)


                            T I D A L   D A T U M S 


Tidal datums at BIG TORCH KEY, WEST SIDE based on:

     LENGTH OF SERIES:      3 MONTHS
     TIME PERIOD:           December 1973 - February 1974
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  8724211 BIG PINE KEY VIADUCT


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

     North American Vertical Datum              NAVD88 =  0.389
     MEAN HIGHER HIGH WATER                     MHHW   =  0.360
     MEAN HIGH WATER                            MHW    =  0.278
     MEAN SEA LEVEL                             MSL    =  0.185
     MEAN TIDE LEVEL                            MTL    =  0.164
     MEAN LOW WATER                             MLW    =  0.050
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     NO 1 1973                                   1.017    0.739
     NO 2 1973                                   0.912    0.634
     NO 3 1973                                   0.925    0.647
     NO 4 1973                                   0.887    0.609
     NO 5 1973                                   0.917    0.639
     4264 F 1982                                 0.589    0.311


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

                                                                                
Station ID: 8724264                         PUBLICATION DATE:  04/29/2004
Name:       BIG TORCH KEY, WEST SIDE                          
            FL
NOAA Chart: 11448                           Latitude:   24° 42.3' N (  24.70500)
USGS Quad:  SUMMERLAND KEY                  Longitude:  81° 26.0' W ( -81.43330)


                             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 8724264 BIG TORCH KEY, WEST SIDE, FL

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