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Bench Mark Sheet for 8724032, PIGEON KEY ATLANTIC 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Superseded Epoch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Small blue map location marker Unpublished bench mark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  5

                                                                                
Station ID: 8724032                         PUBLICATION DATE:  05/28/2004
Name:       PIGEON KEY ATLANTIC SIDE                          
            FL
NOAA Chart: 11449                           Latitude:   24° 42.2' N (  24.70330)
USGS Quad:  SEVEN MILE BRIDGE               Longitude:  81°  9.3' W ( -81.15500)


To reach the tidal bench marks from the Post Office in Marathon, proceed 4.7 km
(2.9 mi) SW along U.S. Highway 1 to the old Seven Mile Bridge, go 3.1 km (1.9
mi) on the old bridge to the ramp leading to Pigeon Key.  The bench marks are
located on the concrete bases of the bridge piers of the old bridge, and near a
shark pool on the south end of the key.  The tide gage and staff were located on
piles 15 m (50 ft) off the south shore. Note:  This bench mark network was also
used for tide station 872 4033, located on the dock at the north end of the key.


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


                 PRIMARY BENCH MARK STAMPING:  NO 1 1935
                         DESIGNATION:          872 4033 TIDAL 1

MONUMENTATION:           Tidal Station disk                    VM#:         6311
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  AA0292
SETTING CLASSIFICATION:  Concrete base                         OPUS PID:        
LATITUDE:   24° 42.3' N (  24.70500)          LONGITUDE:  81°  9.3' W ( -81.15500)


The primary bench mark is a disk set flush in the top of a bridge pier at the
shoreline located on the west side of the key under the old bridge, 10 m (32 ft)
west of the extended centerline of the dock on the north side of the key, 3 m (9
ft) SW of the centerline of a sidewalk, 0.15 m (0.5 ft) north of the north
corner of the bridge pier, and 0.46 m (1.5 ft) above ground level.



                         BENCH MARK STAMPING:  90 70 C17
                         DESIGNATION:           C 17

MONUMENTATION:           Survey disk                           VM#:         6310
AGENCY:                  Florida Department of Transportation
                         (FLDT)                                IDB PID#:  AA0923
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   24° 42.2' N (  24.70330)          LONGITUDE:  81°  9.3' W ( -81.15500)


The bench mark is a disk set in the top of a concrete monument located near the
SW corner of the shark pool, 112 m (369 ft) south of the bridge abutment, 26.03
m (85.4 ft) SW of the NW end of the pool, 5.61 m (18.4 ft) NW of the SW corner
of the pool, 2.83 m (9.3 ft) west of the west end of the pool, 055 m (1.8 ft)
east of a witness post, 0.05 m (0.2 ft) above the ground. 

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

                                                                                
Station ID: 8724032                         PUBLICATION DATE:  05/28/2004
Name:       PIGEON KEY ATLANTIC SIDE                          
            FL
NOAA Chart: 11449                           Latitude:   24° 42.2' N (  24.70330)
USGS Quad:  SEVEN MILE BRIDGE               Longitude:  81°  9.3' W ( -81.15500)


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


                         BENCH MARK STAMPING:  NO 3 1935
                         DESIGNATION:          872 4033 TIDAL 3

MONUMENTATION:           Tidal Station disk                    VM#:         6312
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  AA0291
SETTING CLASSIFICATION:  Concrete base                         OPUS PID:        
LATITUDE:   24° 42.3' N (  24.70500)          LONGITUDE:  81°  9.4' W ( -81.15670)


The bench mark is a disk set flush in the top of the north corner of the
concrete base of a bridge pier located at the shoreline on the west side of the
key under the old bridge, 2 m (6 ft) NE of the extended centerline of the ramp
leading to the key, and 1 m (2 ft) above ground level.

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

                                                                                
Station ID: 8724032                         PUBLICATION DATE:  05/28/2004
Name:       PIGEON KEY ATLANTIC SIDE                          
            FL
NOAA Chart: 11449                           Latitude:   24° 42.2' N (  24.70330)
USGS Quad:  SEVEN MILE BRIDGE               Longitude:  81°  9.3' W ( -81.15500)


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


                         BENCH MARK STAMPING:  MOSER 1935 NO 4 1976
                         DESIGNATION:          MOSER RM 4

MONUMENTATION:           Reference Mark disk                   VM#:         6313
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  AA0924
SETTING CLASSIFICATION:  Concrete floor                        OPUS PID:        
LATITUDE:   24° 42.2' N (  24.70330)          LONGITUDE:  81°  9.3' W ( -81.15500)


The bench mark is a disk set in the SE corner of the concrete floor of a picnic
area located near the shark pool, 24.29 m (79.7 ft) north of bench mark 90 70
C17, 21.00 m (68.9 ft) SSE of the corner of a fence at the entrance to Pigeon
Key, and 0.03 m (0.1 ft) above ground level.

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

                                                                                
Station ID: 8724032                         PUBLICATION DATE:  05/28/2004
Name:       PIGEON KEY ATLANTIC SIDE                          
            FL
NOAA Chart: 11449                           Latitude:   24° 42.2' N (  24.70330)
USGS Quad:  SEVEN MILE BRIDGE               Longitude:  81°  9.3' W ( -81.15500)


                            T I D A L   D A T U M S 


Tidal datums at PIGEON KEY ATLANTIC SIDE based on:

     LENGTH OF SERIES:      1 MONTH
     TIME PERIOD:           April 1975 - April 1975
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  8724138 BAHIA HONDA KEY


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

     North American Vertical Datum              NAVD88 =  0.494
     MEAN HIGHER HIGH WATER                     MHHW   =  0.452
     MEAN HIGH WATER                            MHW    =  0.375
     MEAN SEA LEVEL                             MSL    =  0.213
     MEAN TIDE LEVEL                            MTL    =  0.207
     MEAN LOW WATER                             MLW    =  0.039
     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 1935                                   1.263    0.888
     90 70 C17                                   0.971    0.596
     NO 3 1935                                   1.254    0.880
     MOSER 1935 NO 4 1976                        0.894    0.519


Foot Notes:

Bench mark MOSER 1935 NO 4 1976 is based on one differential leveling connection
and does not meet the quality control standards of the NOS. Therefore, caution
should be used when deriving elevations for this mark.

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

                                                                                
Station ID: 8724032                         PUBLICATION DATE:  05/28/2004
Name:       PIGEON KEY ATLANTIC SIDE                          
            FL
NOAA Chart: 11449                           Latitude:   24° 42.2' N (  24.70330)
USGS Quad:  SEVEN MILE BRIDGE               Longitude:  81°  9.3' W ( -81.15500)


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