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Bench Mark Sheet for 8724436, BIRD 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Superseded Epoch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Small blue map location marker Unpublished bench mark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: 8724436                         PUBLICATION DATE:  02/05/2004
Name:       BIRD KEY                                          
            FL
NOAA Chart: 11445                           Latitude:   24° 35.3' N (  24.58830)
USGS Quad:  BOCA CHICA KEY                  Longitude:  81° 38.3' W ( -81.63830)


To reach the tidal bench marks from the U.S. Highway 1 bridge between Big
Coppitt Key and Saddlebunch Keys, proceed SSE by boat for 1.6 km (1.0 statute
mi) to the northern end of Bird Key.  The bench marks are located along the line
of the old bridge remains at the NW point of the Key.  The tide gage and staff
were located on the NE side and about 91 m (300 ft) SE of the NW point of the
key.


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


                 PRIMARY BENCH MARK STAMPING:  NO 1 1974
                         DESIGNATION:          872 4436 TIDAL 1

MONUMENTATION:           Tidal Station disk                    VM#:         9607
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   24° 35.3' N (  24.58830)          LONGITUDE:  81° 38.3' W ( -81.63830)


The primary bench mark is a disk located in the vicinity of the old bridge
remains located at the NW point of the Key, 28 m (92 ft) SW of the outer edge of
mangroves, 8 m (26 ft) SSW of bench mark NO 3 1974, 0.21 m (0.7 ft) east of a
metal witness post, and 0.18 m (0.6 ft) south of a fibrous witness post.  The
bench mark is 21 cm (0.7 ft) above ground, crimped to the top of a copper-clad
steel rod driven an unspecified depth to refusal, and encased in a 4-inch pipe. 
NOTE: The mark is submerged at high tide.

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

                                                                                
Station ID: 8724436                         PUBLICATION DATE:  02/05/2004
Name:       BIRD KEY                                          
            FL
NOAA Chart: 11445                           Latitude:   24° 35.3' N (  24.58830)
USGS Quad:  BOCA CHICA KEY                  Longitude:  81° 38.3' W ( -81.63830)


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


                         BENCH MARK STAMPING:  NO 2 1974
                         DESIGNATION:          872 4436 TIDAL 2

MONUMENTATION:           Tidal Station disk                    VM#:         9608
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   24° 35.3' N (  24.58830)          LONGITUDE:  81° 38.3' W ( -81.63830)


The bench mark is a disk located in the vicinity of the old bridge remains
located at the NW point of the Key, 4 m (12 ft) SW of the outer edge of
mangroves, 0.18 m (0.6 ft) NW of a metal witness post, and 0.15 m (0.5 ft) SW of
a fibrous witness post.  The bench mark is 21 cm (0.7 ft) above ground, crimped
to the top of a copper-clad steel rod driven an unspecified depth to refusal,
and encased in a 4-inch pipe.  NOTE: The mark is submerged at high tide.



                         BENCH MARK STAMPING:  NO 3 1974
                         DESIGNATION:          872 4436 TIDAL 3

MONUMENTATION:           Tidal Station disk                    VM#:         9609
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   24° 35.3' N (  24.58830)          LONGITUDE:  81° 38.3' W ( -81.63830)


The bench mark is a disk located in the vicinity of the old bridge remains
located at the NW point of the Key, 20 m (66 ft) SW of the outer edge of
mangroves, 16 m (54 ft) SW of bench mark NO 2 1974, 0.70 m (2.3 ft) west of a
witness sign nailed to a tree, and 0.27 m (0.9 ft) SSW of a witness post.  The
bench mark is 21 cm (0.7 ft) above ground, crimped to the top of a copper-clad
steel rod driven an unspecified depth to refusal, and encased in a 4-inch pipe. 
NOTE: The mark is submerged at high tide.

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

                                                                                
Station ID: 8724436                         PUBLICATION DATE:  02/05/2004
Name:       BIRD KEY                                          
            FL
NOAA Chart: 11445                           Latitude:   24° 35.3' N (  24.58830)
USGS Quad:  BOCA CHICA KEY                  Longitude:  81° 38.3' W ( -81.63830)


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


                         BENCH MARK STAMPING:  NO 4 1974
                         DESIGNATION:          872 4436 TIDAL 4

MONUMENTATION:           Tidal Station disk                    VM#:         9610
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   24° 35.3' N (  24.58830)          LONGITUDE:  81° 38.3' W ( -81.63830)


The bench mark is a disk located in the vicinity of the old bridge remains
located at the NW point of the Key, 36 m (119 ft) SW of the outer edge of
mangroves, 8.32 m (27.3 ft) SW of bench mark NO 1 1974, and 0.12 m (0.4 ft) east
of a witness post.  The bench mark is 21 cm (0.7 ft) above ground, crimped to
the top of  a copper-clad steel rod driven an unspecified depth to refusal, and
encased in a 4-inch pipe.  NOTE: The mark is submerged at high tide.



                         BENCH MARK STAMPING:  NO 5 1974
                         DESIGNATION:          872 4436 TIDAL 5

MONUMENTATION:           Tidal Station disk                    VM#:         9611
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   24° 35.3' N (  24.58830)          LONGITUDE:  81° 38.3' W ( -81.63830)


The bench mark is a disk located in the vicinity of the old bridge remains
located at the NW point of the Key, 53 m (174 ft) SW of the outer edge of
mangroves, 16.82 m (55.2 ft) SW of bench mark NO 4 1974, 0.43 m (1.4 ft) SSE of
a metal witness post, and 0.12 m (0.4 ft) WNW of a fibrous witness post.  The
bench mark is 15 cm (0.5 ft) above ground level, crimped to the top of a
copper-clad steel rod driven an unspecified depth to refusal, and encased in a
4-inch pipe.  NOTE: The mark is submerged at high tide.

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

                                                                                
Station ID: 8724436                         PUBLICATION DATE:  02/05/2004
Name:       BIRD KEY                                          
            FL
NOAA Chart: 11445                           Latitude:   24° 35.3' N (  24.58830)
USGS Quad:  BOCA CHICA KEY                  Longitude:  81° 38.3' W ( -81.63830)


                            T I D A L   D A T U M S 


Tidal datums at BIRD KEY based on:

     LENGTH OF SERIES:      2 MONTHS
     TIME PERIOD:           April 1974 - May 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:

     MEAN HIGHER HIGH WATER                     MHHW   =  0.338
     MEAN HIGH WATER                            MHW    =  0.269
     MEAN SEA LEVEL                             MSL    =  0.151
     MEAN TIDE LEVEL                            MTL    =  0.148
     MEAN LOW WATER                             MLW    =  0.028
     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 1974                                   0.268   -0.001
     NO 2 1974                                   0.164   -0.105
     NO 3 1974                                   0.300    0.031
     NO 4 1974                                   0.308    0.039
     NO 5 1974                                   0.284    0.015


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

                                                                                
Station ID: 8724436                         PUBLICATION DATE:  02/05/2004
Name:       BIRD KEY                                          
            FL
NOAA Chart: 11445                           Latitude:   24° 35.3' N (  24.58830)
USGS Quad:  BOCA CHICA KEY                  Longitude:  81° 38.3' W ( -81.63830)


                             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 8724436 BIRD KEY, FL

Revised: 10/15/2013
NOAA / National Ocean Service
Web site owner: Center for Operational Oceanographic Products and Services