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Bench Mark Sheet for 8724369, SAWYER KEY (INSIDE) 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Superseded Epoch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Small blue map location marker Unpublished bench mark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  8

                                                                                
Station ID: 8724369                         PUBLICATION DATE:  02/05/2004
Name:       SAWYER KEY (INSIDE)                               
            FL
NOAA Chart: 11434                           Latitude:   24° 45.5' N (  24.75830)
USGS Quad:  SAWYER KEY                      Longitude:  81° 33.7' W ( -81.56170)


To reach the tidal bench marks from Doctors Point, Big Pine Key, proceed by boat
NW for 19.6 km (14 nm) along the Intracoastal Waterway, then continue NW between
red channel markers #74 and #76 into Cudjoe Channel for 4.6 km (3.3 nm) to
Sawyer Keys.  The bench marks are on the northernmost key of Sawyer Keys.  The
tide gage and staff were off the south central shore of the northernmost key.


                         T I D A L   B E N C H   M A R K S
                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  8

                                                                                
Station ID: 8724369                         PUBLICATION DATE:  02/05/2004
Name:       SAWYER KEY (INSIDE)                               
            FL
NOAA Chart: 11434                           Latitude:   24° 45.5' N (  24.75830)
USGS Quad:  SAWYER KEY                      Longitude:  81° 33.7' W ( -81.56170)


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


                 PRIMARY BENCH MARK STAMPING:  SAWYER 2 1934 NO 2
                         DESIGNATION:          SAWYER 2 RM 2
                         ALIAS:                1

MONUMENTATION:           Reference Mark disk                   VM#:         7018
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  AE4415
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   24° 45.6' N (  24.76000)          LONGITUDE:  81° 33.6' W ( -81.56000)


The primary bench mark is a disk set in a concrete block on the north side of
the key, 152 m (500 ft) SW of the NE end of the key, 4.02 m (13.2 ft) south of
the approximate mean high water line, and 0.30 m (1.0 ft) above ground level. 
Note: The stamping is no longer legible.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  8

                                                                                
Station ID: 8724369                         PUBLICATION DATE:  02/05/2004
Name:       SAWYER KEY (INSIDE)                               
            FL
NOAA Chart: 11434                           Latitude:   24° 45.5' N (  24.75830)
USGS Quad:  SAWYER KEY                      Longitude:  81° 33.7' W ( -81.56170)


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


                         BENCH MARK STAMPING:  SAWYER 2 1934
                         DESIGNATION:          SAWYER 2
                         ALIAS:                2

MONUMENTATION:           Triangulation Station disk            VM#:         7016
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  AA1617
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   24° 45.6' N (  24.76000)          LONGITUDE:  81° 33.6' W ( -81.56000)


The bench mark is a disk set in a concrete monument on a sand ridge on the north
side of the northernmost key of Sawyer Keys, about 151 m (495 ft) SW of the NE
end of the key, 20 m (66 ft) south of the north side of the key, and 0.30 m (1.0
ft) above ground level.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  8

                                                                                
Station ID: 8724369                         PUBLICATION DATE:  02/05/2004
Name:       SAWYER KEY (INSIDE)                               
            FL
NOAA Chart: 11434                           Latitude:   24° 45.5' N (  24.75830)
USGS Quad:  SAWYER KEY                      Longitude:  81° 33.7' W ( -81.56170)


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


                         BENCH MARK STAMPING:  SAWYER 2 1934 NO 1
                         DESIGNATION:          SAWYER 2 RM 1
                         ALIAS:                3

MONUMENTATION:           Reference Mark disk                   VM#:         7017
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  AE4414
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   24° 45.6' N (  24.76000)          LONGITUDE:  81° 33.6' W ( -81.56000)


The bench mark is a disk set in the top of a concrete monument, 20 m (66 ft)
south of the north side of the key, 6.28 m (20.6 ft) NE of the remains of an old
lighthouse, and 0.30 m (1.0 ft) above ground level.  NOTE: Mark not found in
1984 by is believed to exist.



                         BENCH MARK STAMPING:  NO 4 1973
                         DESIGNATION:          872 4369 TIDAL 4

MONUMENTATION:           Tidal Station disk                    VM#:         7019
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Rock and concrete tub                 OPUS PID:        
LATITUDE:   24° 45.5' N (  24.75830)          LONGITUDE:  81° 33.7' W ( -81.56170)


The bench mark is a disk set in rock and concrete tub in the ruins of a concrete
basin on the north side of the key, 125.73 m (412.5 ft) SW of the NE end of the
key, 24.87 m (81.6 ft) east of bench mark SAWYER 2 1934 NO 2, and 0.30 m (1.0
ft) ENE of the SW corner of the ruins.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  5 of  8

                                                                                
Station ID: 8724369                         PUBLICATION DATE:  02/05/2004
Name:       SAWYER KEY (INSIDE)                               
            FL
NOAA Chart: 11434                           Latitude:   24° 45.5' N (  24.75830)
USGS Quad:  SAWYER KEY                      Longitude:  81° 33.7' W ( -81.56170)


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


                         BENCH MARK STAMPING:  NO 5 1973
                         DESIGNATION:          872 4369 TIDAL 5

MONUMENTATION:           Tidal Station disk                    VM#:         7020
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Rock                                  OPUS PID:        
LATITUDE:   24° 45.5' N (  24.75830)          LONGITUDE:  81° 33.7' W ( -81.56170)


The bench mark is a disk set in a rock on the north side of the key, 124.74 m
(409.2 ft) SW of the NE end of the key, 25.60 m (84.0 ft) ENE of bench mark
SAWYER 2 NO 2 1934, 11.95 m (39.2 ft) NE of the SW corner of the ruins of the
concrete basin, 12 m (39 ft) north of bench mark NO 4 1973, and 7.56 m (24.8 ft)
NNW of the NE corner of the basin ruins.



                         BENCH MARK STAMPING:  4369 F 1984
                         DESIGNATION:          872 4369 F

MONUMENTATION:           Tidal Station disk                    VM#:         7021
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Rock                                  OPUS PID:        
LATITUDE:   24° 45.5' N (  24.75830)          LONGITUDE:  81° 33.7' W ( -81.56170)


The bench mark is a disk set in rock located on the north side of the key, 38.40
m (126.0 ft) ENE of bench mark 4369 G 1984, and 0.03 m (0.1 ft) above the rock
surface.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  6 of  8

                                                                                
Station ID: 8724369                         PUBLICATION DATE:  02/05/2004
Name:       SAWYER KEY (INSIDE)                               
            FL
NOAA Chart: 11434                           Latitude:   24° 45.5' N (  24.75830)
USGS Quad:  SAWYER KEY                      Longitude:  81° 33.7' W ( -81.56170)


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


                         BENCH MARK STAMPING:  4369 G 1984
                         DESIGNATION:          872 4369 G

MONUMENTATION:           Tidal Station disk                    VM#:         7022
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Rock                                  OPUS PID:        
LATITUDE:   24° 45.5' N (  24.75830)          LONGITUDE:  81° 33.7' W ( -81.56170)


The bench mark is a disk set in rock located on the north side of the key, 18.65
m (61.2 ft) NE of bench mark NO 4 1973, 13 m (43 ft) ENE of bench mark NO 5
1973, and 0.03 m (0.1 ft) above the rock surface.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  7 of  8

                                                                                
Station ID: 8724369                         PUBLICATION DATE:  02/05/2004
Name:       SAWYER KEY (INSIDE)                               
            FL
NOAA Chart: 11434                           Latitude:   24° 45.5' N (  24.75830)
USGS Quad:  SAWYER KEY                      Longitude:  81° 33.7' W ( -81.56170)


                            T I D A L   D A T U M S 


Tidal datums at SAWYER KEY (INSIDE) based on:

     LENGTH OF SERIES:      3 MONTHS
     TIME PERIOD:           December 1973 - February 1974
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  8724580 KEY WEST


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

     MEAN HIGHER HIGH WATER                     MHHW   =  0.744
     MEAN HIGH WATER                            MHW    =  0.662
     MEAN TIDE LEVEL                            MTL    =  0.349
     MEAN SEA LEVEL                             MSL    =  0.315
     MEAN LOW WATER                             MLW    =  0.036
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     SAWYER 2 1934 NO 2                          1.001    0.339
     SAWYER 2 1934                               1.734    1.072
     SAWYER 2 1934 NO 1                          1.751    1.089
     NO 4 1973                                   1.168    0.506
     NO 5 1973                                   0.813    0.151
     4369 F 1984                                 0.689    0.027
     4369 G 1984                                 0.705    0.043


Foot Notes:

Bench marks SAWYER 2 1934, 4369 F 1984 and 4369 G 1984 are based on
onedifferential leveling connection and do not meet the quality control
standardsof the NOS.  Therefore, caution should be used when deriving elevations
forthese marks. 

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  8 of  8

                                                                                
Station ID: 8724369                         PUBLICATION DATE:  02/05/2004
Name:       SAWYER KEY (INSIDE)                               
            FL
NOAA Chart: 11434                           Latitude:   24° 45.5' N (  24.75830)
USGS Quad:  SAWYER KEY                      Longitude:  81° 33.7' W ( -81.56170)


                             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 8724369 SAWYER KEY (INSIDE), FL

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