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Bench Mark Sheet for 8723746, CRANE 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Superseded Epoch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Small blue map location marker Unpublished bench mark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  5

                                                                                
Station ID: 8723746                         PUBLICATION DATE:  05/23/2003
Name:       CRANE KEY                                         
            FL
NOAA Chart: 11452                           Latitude:   25°  0.3' N (  25.00500)
USGS Quad:  Tavernier                       Longitude:  80° 37.1' W ( -80.61830)


To reach the tidal bench marks from the U.S. Highway 1 bridge over Snake Creek,
Windley Key, proceed by boat 7.6 km (4.7 mi) NNW to the NW side of the largest
of the Crane Keys.  The bench marks are located in a clear area, 0.3 km (0.2 mi)
NE of the SW end of Crane Key.  The tide gage and staff were located off the NW
shore of the largest Crane Key.


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


                 PRIMARY BENCH MARK STAMPING:  NO 1 1975
                         DESIGNATION:          Crane Key Tidal 1

MONUMENTATION:           Bench Mark disk                       VM#:         5994
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  AC4848
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   25°  0.3' N (  25.00500)          LONGITUDE:  80° 37.1' W ( -80.61830)


The primary bench mark is a disk located on the edge of a tidal pond, 20.24 m
(66.4 ft) NE of Bench Mark NO 2 1975, 10.85 m (35.6 ft) SE of the NW shoreline,
and 0.24 m (0.8 ft) NW of a witness post.  The bench mark is set 0.09 m (0.3 ft)
above the ground, crimped to a copper-clad steel rod driven to refusal, and
encased in concrete.

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

                                                                                
Station ID: 8723746                         PUBLICATION DATE:  05/23/2003
Name:       CRANE KEY                                         
            FL
NOAA Chart: 11452                           Latitude:   25°  0.3' N (  25.00500)
USGS Quad:  Tavernier                       Longitude:  80° 37.1' W ( -80.61830)


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


                         BENCH MARK STAMPING:  NO 2 1975
                         DESIGNATION:          872 3746 TIDAL 2

MONUMENTATION:           Survey disk                           VM#:         5995
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   25°  0.3' N (  25.00500)          LONGITUDE:  80° 37.1' W ( -80.61830)


The bench mark is a disk located on the edge of a tidal pond, 22 m (72 ft) NE of
Bench Mark NO 4 1975, 20 m (66 ft) SW of Bench Mark NO 1 1975, 14.14 m (46.4 ft)
NE of an Everglades National Park sign, and 0.24 m (0.8 ft) east of a witness
post.  The bench mark is set 0.06 m (0.2 ft) above the ground, crimped to a
copper-clad steel rod driven to refusal, and encased in concrete.



                         BENCH MARK STAMPING:  NO 4 1975
                         DESIGNATION:          872 3746 TIDAL 4

MONUMENTATION:           Survey disk                           VM#:         5996
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   25°  0.3' N (  25.00500)          LONGITUDE:  80° 37.1' W ( -80.61830)


The bench mark is a disk located 21.76 m (71.4 ft) SW of Bench Mark NO 2 1975,
17.53 m (57.5 ft) NE of Bench Mark NO 5 1975, 8.35 m (27.4 ft) south of an
Everglades National Park sign, and 0.24 m (0.8 ft) NW of a witness post.  The
bench mark is set 0.12 m (0.4 ft) above the ground, crimped to a copper-clad
steel rod driven to refusal, and encased in concrete.

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

                                                                                
Station ID: 8723746                         PUBLICATION DATE:  05/23/2003
Name:       CRANE KEY                                         
            FL
NOAA Chart: 11452                           Latitude:   25°  0.3' N (  25.00500)
USGS Quad:  Tavernier                       Longitude:  80° 37.1' W ( -80.61830)


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


                         BENCH MARK STAMPING:  NO 5 1975
                         DESIGNATION:          872 3746 TIDAL 5

MONUMENTATION:           Survey disk                           VM#:         5997
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   25°  0.3' N (  25.00500)          LONGITUDE:  80° 37.1' W ( -80.61830)


The bench mark is a disk located 25 m (82 ft) SSW of an Everglades National Park
sign, 17.53 m (57.5 ft) SW of Bench Mark NO 4 1975, and 0.40 m (1.3 ft) NW of a
witness post.  The bench mark is set 0.06 m (0.2 ft) above the ground, crimped
to a copper-clad steel rod driven to refusal, and encased in concrete.



                         BENCH MARK STAMPING:  3746 F 1984
                         DESIGNATION:          872 3746 F

MONUMENTATION:           Survey disk                           VM#:         5998
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Stainless steel rod                   OPUS PID:        
LATITUDE:   25°  0.3' N (  25.00500)          LONGITUDE:  80° 37.1' W ( -80.61830)


The bench mark is a disk located on the edge of a tidal pond, 30.11 m (98.8 ft)
ESE of an Everglades National Park sign, 29.23 m (95.9 ft) south of Bench Mark
NO 1 1975, 23.96 m (78.6 ft) SE of Bench Mark NO 2 1975, and 4 m (12 ft) north
of a witness post.  The bench mark is set 0.06 m (0.2 ft) above the ground,
crimped to a stainless steel rod driven 5 m (16 ft) to refusal, and encased in a
PVC pipe and concrete kickblock.

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

                                                                                
Station ID: 8723746                         PUBLICATION DATE:  05/23/2003
Name:       CRANE KEY                                         
            FL
NOAA Chart: 11452                           Latitude:   25°  0.3' N (  25.00500)
USGS Quad:  Tavernier                       Longitude:  80° 37.1' W ( -80.61830)


                            T I D A L   D A T U M S 


Tidal datums at CRANE KEY based on:

     LENGTH OF SERIES:      1 MONTH
     TIME PERIOD:           June 1975 - June 1975
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  8723852 LOWER MATECUMBE KEY, FLA. BAY


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

     MEAN HIGHER HIGH WATER                     MHHW   =  0.152
     MEAN HIGH WATER                            MHW    =  0.128
     MEAN TIDE LEVEL                            MTL    =  0.068
     MEAN SEA LEVEL                             MSL    =  0.062
     MEAN LOW WATER                             MLW    =  0.008
     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 1975                                   0.238    0.110
     NO 2 1975                                   0.237    0.109
     NO 4 1975                                   0.358    0.230
     NO 5 1975                                   0.359    0.231
     3746 F 1984                                 0.233    0.105


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

                                                                                
Station ID: 8723746                         PUBLICATION DATE:  05/23/2003
Name:       CRANE KEY                                         
            FL
NOAA Chart: 11452                           Latitude:   25°  0.3' N (  25.00500)
USGS Quad:  Tavernier                       Longitude:  80° 37.1' W ( -80.61830)


                             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 8723746 CRANE KEY, FL

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