Bench Mark Sheet for 8724422, SIMILAR SOUND 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Superseded Epoch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Small blue map location marker Unpublished bench mark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: 8724422                         PUBLICATION DATE:  02/05/2004
Name:       SIMILAR SOUND                                     
            FL
NOAA Chart: 11445                           Latitude:   24° 36.0' N (  24.60000)
USGS Quad:  SADDLEBUNCH KEYS                Longitude:  81° 37.3' W ( -81.62170)


To reach the tidal bench marks from the NE end of the U.S. Highway 1 bridge over
Channel No. 5, proceed by boat south for 1.3 km (0.8 statute mi) to the SW end
of a small peninsula of Saddlebunch Keys on the east side of Similar Sound.  The
bench marks are located at the SW end of the peninsula.  The tide gage and staff
were located offshore of the end of the peninsula.


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


                 PRIMARY BENCH MARK STAMPING:  NO 1 1974
                         DESIGNATION:          872 4422 TIDAL 1

MONUMENTATION:           Tidal Station disk                    VM#:         9591
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   24° 36.0' N (  24.60000)          LONGITUDE:  81° 37.3' W ( -81.62170)


The primary bench mark is a disk set in a concrete monument atop a copper-clad
steel rod driven to refusal, 18.29 m (60.0 ft) east of the NW most point of the
SW end of the peninsula, 9 m (30 ft) NE of the water line on a high sand berm,
0.18 m (0.6 ft) south of a witness post, and at ground level.

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

                                                                                
Station ID: 8724422                         PUBLICATION DATE:  02/05/2004
Name:       SIMILAR SOUND                                     
            FL
NOAA Chart: 11445                           Latitude:   24° 36.0' N (  24.60000)
USGS Quad:  SADDLEBUNCH KEYS                Longitude:  81° 37.3' W ( -81.62170)


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


                         BENCH MARK STAMPING:  NO 2 1974
                         DESIGNATION:          872 4422 TIDAL 2

MONUMENTATION:           Tidal Station disk                    VM#:         9592
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   24° 36.0' N (  24.60000)          LONGITUDE:  81° 37.3' W ( -81.62170)


The bench mark is a disk set in a concrete monument atop a copper-clad steel rod
driven to refusal, 38 m (124 ft) SE of the NW most point of the SW end of the
peninsula, 21 m (70 ft) ESE of bench mark NO 1 1974, 3 m (11 ft) west of the
east side of the sand berm, 9 m (30 ft) NE of the water line on a high sand
berm, 0.18 m (0.6 ft) WSW of a witness post, and 0.06 m (0.2 ft) above ground
level.



                         BENCH MARK STAMPING:  NO 3 1974
                         DESIGNATION:          872 4422 TIDAL 3

MONUMENTATION:           Tidal Station disk                    VM#:         9593
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   24° 36.0' N (  24.60000)          LONGITUDE:  81° 37.3' W ( -81.62170)


The bench mark is a disk set in a concrete monument atop a copper-clad steel rod
driven to refusal, 14.54 m (47.7 ft) NE of bench mark NO 2 1974, 8 m (25 ft)
east of the water line, 6 m (20 ft) east of the east side of the high sand berm,
0.24 m (0.8 ft) east of a witness post, and 0.06 m (0.2 ft) above ground level.

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

                                                                                
Station ID: 8724422                         PUBLICATION DATE:  02/05/2004
Name:       SIMILAR SOUND                                     
            FL
NOAA Chart: 11445                           Latitude:   24° 36.0' N (  24.60000)
USGS Quad:  SADDLEBUNCH KEYS                Longitude:  81° 37.3' W ( -81.62170)


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


                         BENCH MARK STAMPING:  NO 4 1974
                         DESIGNATION:          872 4422 TIDAL 4

MONUMENTATION:           Tidal Station disk                    VM#:         9594
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   24° 36.0' N (  24.60000)          LONGITUDE:  81° 37.3' W ( -81.62170)


The bench mark is a disk set in a concrete monument atop a copper-clad steel rod
driven to refusal, located 53 m (175 ft) NNW of the south side of the peninsula,
30 m (100 ft) SSE of the north side of the peninsula, 21 m (69 ft) SE of bench
mark NO 3 1974, 0.24 m (0.8 ft) NE of a witness post, and 0.06 m (0.2 ft) above
ground level.



                         BENCH MARK STAMPING:  NO 5 1974
                         DESIGNATION:          872 4422 TIDAL 5

MONUMENTATION:           Tidal Station disk                    VM#:         9595
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   24° 36.0' N (  24.60000)          LONGITUDE:  81° 37.3' W ( -81.62170)


The bench mark is a disk set in a concrete monument atop a copper-clad steel rod
driven to refusal, on a high sand berm, 91 m (300 ft) ESE of the NW most point
of the SW end of the peninsula, 41.70 m (136.8 ft) ENE of bench mark NO 4 1974,
9 m (29 ft) south of the water line on the north side of the peninsula, 0.30 m
(1.0 ft) SSW of a witness post, and 0.24 m (0.8 ft) above ground level.

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

                                                                                
Station ID: 8724422                         PUBLICATION DATE:  02/05/2004
Name:       SIMILAR SOUND                                     
            FL
NOAA Chart: 11445                           Latitude:   24° 36.0' N (  24.60000)
USGS Quad:  SADDLEBUNCH KEYS                Longitude:  81° 37.3' W ( -81.62170)


                            T I D A L   D A T U M S 


Tidal datums at SIMILAR SOUND 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   =  0.237
     MEAN HIGH WATER                            MHW    =  0.168
     MEAN SEA LEVEL                             MSL    =  0.098
     MEAN TIDE LEVEL                            MTL    =  0.091
     MEAN LOW WATER                             MLW    =  0.014
     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                                   0.566    0.398
     NO 2 1974                                   0.718    0.550
     NO 3 1974                                   0.284    0.116
     NO 4 1974                                   0.143   -0.025
     NO 5 1974                                   0.582    0.414


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

                                                                                
Station ID: 8724422                         PUBLICATION DATE:  02/05/2004
Name:       SIMILAR SOUND                                     
            FL
NOAA Chart: 11445                           Latitude:   24° 36.0' N (  24.60000)
USGS Quad:  SADDLEBUNCH KEYS                Longitude:  81° 37.3' W ( -81.62170)


                             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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