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Bench Mark Sheet for 8724311, RACOON KEY 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Superseded Epoch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Small blue map location marker Unpublished bench mark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: 8724311                         PUBLICATION DATE:  06/28/2004
Name:       RACOON KEY                                        
            FL
NOAA Chart: 11448                           Latitude:   24° 44.5' N (  24.74170)
USGS Quad:  SUMMERLAND KEY                  Longitude:  81° 29.0' W ( -81.48330)


To reach the tidal bench marks from the west end of the bridge between Ramrod
Key and Summerland Key, proceed north by boat for 4.3 km (3.1 nm) and then NW
for 7.0 km (5.1 nm) to Raccoon Key.  The bench marks are located about the
middle of the Key and closer to the east shore.  The tide gage and staff were
located about 0.5 km (0.3 mi) east of the SE shore.


                         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  7

                                                                                
Station ID: 8724311                         PUBLICATION DATE:  06/28/2004
Name:       RACOON KEY                                        
            FL
NOAA Chart: 11448                           Latitude:   24° 44.5' N (  24.74170)
USGS Quad:  SUMMERLAND KEY                  Longitude:  81° 29.0' W ( -81.48330)


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


                 PRIMARY BENCH MARK STAMPING:  RAC 1935
                         DESIGNATION:          RAC 1935
                         ALIAS:                3

MONUMENTATION:           Triangulation Station disk            VM#:         6929
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  AA1563
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   24° 44.5' N (  24.74170)          LONGITUDE:  81° 29.4' W ( -81.49000)


The primary bench mark is a disk set in the top of a 0.24 m (0.8 ft) square
concrete monument located 0.40 km (0.25 mi) north of the southern point of the
Key, 39.96 m (131.1 ft) SSE of bench mark 4311 F 1984, 37 m (121 ft) inshore of
the outer mangroves on the SE shore, and 0.21 m (0.7 ft) above the ground.

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

                                                                                
Station ID: 8724311                         PUBLICATION DATE:  06/28/2004
Name:       RACOON KEY                                        
            FL
NOAA Chart: 11448                           Latitude:   24° 44.5' N (  24.74170)
USGS Quad:  SUMMERLAND KEY                  Longitude:  81° 29.0' W ( -81.48330)


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


                         BENCH MARK STAMPING:  RAC 1935 RM NO 1
                         DESIGNATION:          RAC RM 1
                         ALIAS:                2

MONUMENTATION:           Reference Mark disk                   VM#:         6930
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:        
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   24° 44.5' N (  24.74170)          LONGITUDE:  81° 29.0' W ( -81.48330)


The bench mark is a disk set in the top of a 0.24 m (0.8 ft) square concrete
monument, 26.00 m (85.3 ft) WSW of triangulation station RAC 1935, 0.70 m (2.3
ft) east of a witness post, and 0.21 m (0.7 ft) above the ground.

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

                                                                                
Station ID: 8724311                         PUBLICATION DATE:  06/28/2004
Name:       RACOON KEY                                        
            FL
NOAA Chart: 11448                           Latitude:   24° 44.5' N (  24.74170)
USGS Quad:  SUMMERLAND KEY                  Longitude:  81° 29.0' W ( -81.48330)


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


                         BENCH MARK STAMPING:  RAC 1935 RM NO 2
                         DESIGNATION:          RAC RM 2
                         ALIAS:                1

MONUMENTATION:           Reference Mark disk                   VM#:         6931
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:        
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   24° 44.5' N (  24.74170)          LONGITUDE:  81° 29.0' W ( -81.48330)


The bench mark is a disk set in the top of a 0.24 m (0.8 ft) square concrete
monument, 26.18 m (85.9 ft) NW of triangulation station RAC 1935, 1.31 m (4.3
ft) east of a witness post, and 0.21 m (0.7 ft) above the ground.



                         BENCH MARK STAMPING:  NO 4 1974
                         DESIGNATION:          872 4311 TIDAL 4

MONUMENTATION:           Tidal Station disk                    VM#:         6932
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Copper-clad rod                       OPUS PID:        
LATITUDE:   24° 44.5' N (  24.74170)          LONGITUDE:  81° 29.0' W ( -81.48330)


The bench mark is a disk located among the mangrove trees, 10.36 m (34.0 ft) ENE
of bench mark NO 5 1974, 8 m (25 ft) west of the outer mangrove edge on the east
shore, 1.77 m (5.8 ft) north of a witness sign nailed to a tree, and 0.61 m (2.0
ft) WSW of a witness post.  The bench mark is set 6 cm (0.2 ft) above the
ground, crimped to the top fo a copper-clad rod driven an unspecified depth to
refusal.

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

                                                                                
Station ID: 8724311                         PUBLICATION DATE:  06/28/2004
Name:       RACOON KEY                                        
            FL
NOAA Chart: 11448                           Latitude:   24° 44.5' N (  24.74170)
USGS Quad:  SUMMERLAND KEY                  Longitude:  81° 29.0' W ( -81.48330)


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


                         BENCH MARK STAMPING:  NO 5 1974
                         DESIGNATION:          872 4311 TIDAL 5

MONUMENTATION:           Tidal Station disk                    VM#:         6933
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Copper-clad rod                       OPUS PID:        
LATITUDE:   24° 44.5' N (  24.74170)          LONGITUDE:  81° 29.0' W ( -81.48330)


The bench mark is a disk located at the edge of a clearing, 27.74 m (91.0 ft)
east of bench mark RAC 1935 RM NO 2, 20.91 m (68.6 ft) NNE of triangulation
station RAC 1935, and 0.67 m (2.2 ft) ENE of a witness post.  The bench mark is
set 15 cm (0.5 ft) above the ground, crimped to the top of a copper-clad rod
driven an unspecified depth to refusal.



                         BENCH MARK STAMPING:  4311 F 1984
                         DESIGNATION:          872 4311 F TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         6934
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Bedrock                               OPUS PID:        
LATITUDE:   24° 44.5' N (  24.74170)          LONGITUDE:  81° 29.0' W ( -81.48330)


The bench mark is a disk set in concrete poured in a hole in the bedrock, 40 m
(131 ft) NW of triangulation station RAC 1935, 31.39 m (103.0 ft) NW of bench
mark NO 5 1974, 17.83 m (58.5 ft) NNE of bench mark RAC 1935 RM NO 2, 1.92 m
(6.3 ft) ENE of a witness post, and 0.15 m (0.5 ft) above ground level.

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

                                                                                
Station ID: 8724311                         PUBLICATION DATE:  06/28/2004
Name:       RACOON KEY                                        
            FL
NOAA Chart: 11448                           Latitude:   24° 44.5' N (  24.74170)
USGS Quad:  SUMMERLAND KEY                  Longitude:  81° 29.0' W ( -81.48330)


                            T I D A L   D A T U M S 


Tidal datums at RACOON KEY based on:

     LENGTH OF SERIES:      1 MONTH
     TIME PERIOD:           September 1974 - September 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   =  0.786
     MEAN HIGH WATER                            MHW    =  0.696
     MEAN TIDE LEVEL                            MTL    =  0.392
     MEAN SEA LEVEL                             MSL    =  0.388
     MEAN LOW WATER                             MLW    =  0.088
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     RAC 1935                                    1.078    0.382
     RAC 1935 RM NO 1                            1.098    0.402
     RAC 1935 RM NO 2                            1.007    0.311
     NO 4 1974                                   0.987    0.291
     NO 5 1974                                   1.023    0.327
     4311 F 1984                                 1.063    0.367


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

                                                                                
Station ID: 8724311                         PUBLICATION DATE:  06/28/2004
Name:       RACOON KEY                                        
            FL
NOAA Chart: 11448                           Latitude:   24° 44.5' N (  24.74170)
USGS Quad:  SUMMERLAND KEY                  Longitude:  81° 29.0' W ( -81.48330)


                             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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