Bench Mark Sheet for 8724423, SADDLEBUNCH CHANNEL NO. 5 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Superseded Epoch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Small blue map location marker Unpublished bench mark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: 8724423                         PUBLICATION DATE:  02/05/2004
Name:       SADDLEBUNCH CHANNEL NO. 5                         
            FL
NOAA Chart: 11442                           Latitude:   24° 36.7' N (  24.61170)
USGS Quad:  SADDLEBUNCH KEYS                Longitude:  81° 37.4' W ( -81.62330)


To reach the tidal bench marks from the Catholic Church in Key West, proceed
19.2 km (11.9 mi) NE on U.S. Highway 1 to the NE end of the bridge over
Saddlebunch Channel No. 5.  The bench marks are in the vicinity of the old U.S.
Highway 1 bridge (now a fishing pier) and the U.S. Highway 1 bridge.  The tide
gage and staff were located west of the north wing wall of the old U.S. Highway
1 bridge (fishing pier).


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


                 PRIMARY BENCH MARK STAMPING:  NO 4 1975
                         DESIGNATION:          872 4423 TIDAL 4

MONUMENTATION:           Tidal Station disk                    VM#:         9599
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  AA0771
SETTING CLASSIFICATION:  Concrete footing                      OPUS PID:        
LATITUDE:   24° 36.7' N (  24.61170)          LONGITUDE:  81° 37.4' W ( -81.62330)


The primary bench mark is a disk set in the concrete footing of the first
concrete power pole east of the U.S. Highway 1 bridge over Saddlebunch Channel
No. 5, 20 m (64 ft) SE of the centerline of U.S. Highway 1, 0.30 m (1.0 ft) NW
of the power pole, and 3 m (9 ft) below U.S. Highway 1.

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

                                                                                
Station ID: 8724423                         PUBLICATION DATE:  02/05/2004
Name:       SADDLEBUNCH CHANNEL NO. 5                         
            FL
NOAA Chart: 11442                           Latitude:   24° 36.7' N (  24.61170)
USGS Quad:  SADDLEBUNCH KEYS                Longitude:  81° 37.4' W ( -81.62330)


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


                         BENCH MARK STAMPING:  NO 1 1975
                         DESIGNATION:          872 4423 TIDAL 1

MONUMENTATION:           Tidal Station disk                    VM#:         9596
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  AA0769
SETTING CLASSIFICATION:  Concrete wing wall                    OPUS PID:        
LATITUDE:   24° 36.7' N (  24.61170)          LONGITUDE:  81° 37.4' W ( -81.62330)


The bench mark is a disk set in the north wing wall located at the NE end of the
old U.S. Highway 1 bridge (now a fishing pier), 5 m (15 ft) NW of the centerline
of the old U.S. Highway 1 bridge (fishing pier), 5 m (15 ft) west of the NE end
of the old bridge (fishing pier) guardrail, 0.76 m (2.5 ft) NW of the NW edge of
the old bridge (fishing pier), and 1 m (3 ft) below the roadway.



                         BENCH MARK STAMPING:  NO 2 1975
                         DESIGNATION:          872 4423 TIDAL 2

MONUMENTATION:           Tidal Station disk                    VM#:         9597
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  AA0767
SETTING CLASSIFICATION:  Concrete wing wall                    OPUS PID:        
LATITUDE:   24° 36.7' N (  24.61170)          LONGITUDE:  81° 37.4' W ( -81.62330)


The bench mark is a disk set in the south wing wall located at the NE end of the
old U.S. Highway 1 bridge (now a fishing pier), 4 m (14 ft) SE of the centerline
of the old U.S. Highway 1 bridge (fishing pier), 0.76 m (2.5 ft) SE of the SE
edge of the old bridge (fishing pier), and 1 m (3 ft) below the roadway.

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

                                                                                
Station ID: 8724423                         PUBLICATION DATE:  02/05/2004
Name:       SADDLEBUNCH CHANNEL NO. 5                         
            FL
NOAA Chart: 11442                           Latitude:   24° 36.7' N (  24.61170)
USGS Quad:  SADDLEBUNCH KEYS                Longitude:  81° 37.4' W ( -81.62330)


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


                         BENCH MARK STAMPING:  NO 3 1975
                         DESIGNATION:          872 4423 TIDAL 3

MONUMENTATION:           Tidal Station disk                    VM#:         9598
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  AA0768
SETTING CLASSIFICATION:  Concrete wing wall                    OPUS PID:        
LATITUDE:   24° 36.7' N (  24.61170)          LONGITUDE:  81° 37.4' W ( -81.62330)


The bench mark is a disk set in the south wing wall located at the NE end of the
old U.S. Highway 1 bridge (now a fishing pier), 12 m (41 ft) SE of the
centerline of the old U.S. Highway 1 bridge (fishing pier), 10.82 m (35.5 ft) SE
of the SE edge of the old bridge (fishing pier), and 2 m (7 ft) below the
roadway.



                         BENCH MARK STAMPING:  4423 F
                         DESIGNATION:          872 4423 F TIDAL

MONUMENTATION:           Bench Mark disk                       VM#:         9600
AGENCY:                  Florida Department of Transportation
                         (FLDT)                                IDB PID#:  AA0770
SETTING CLASSIFICATION:  Concrete bridge guardrail             OPUS PID:        
LATITUDE:   24° 36.7' N (  24.61170)          LONGITUDE:  81° 37.4' W ( -81.62330)


The bench mark is a disk set in the concrete guardrail located at the NE end of
U.S. Highway 1 bridge over Saddlebunch Channel No. 5, 7.10 m (23.3 ft) SE of the
centerline of U.S. Highway 1, 3.11 m (10.2 ft) SW of the NE end of the
guardrail, 1.49 m (4.9 ft) NW of the SE bridge cheekwall, 0.30 m (1.0 ft) NE of
the abutment, and 1 m (3 ft) above U.S. Highway 1.

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

                                                                                
Station ID: 8724423                         PUBLICATION DATE:  02/05/2004
Name:       SADDLEBUNCH CHANNEL NO. 5                         
            FL
NOAA Chart: 11442                           Latitude:   24° 36.7' N (  24.61170)
USGS Quad:  SADDLEBUNCH KEYS                Longitude:  81° 37.4' W ( -81.62330)


                            T I D A L   D A T U M S 


Tidal datums at SADDLEBUNCH CHANNEL NO. 5 based on:

     LENGTH OF SERIES:      1 MONTH
     TIME PERIOD:           February 1975 - February 1975
     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   =  0.388
     MEAN HIGH WATER                            MHW    =  0.306
     North American Vertical Datum              NAVD88 =  0.292
     MEAN SEA LEVEL                             MSL    =  0.197
     MEAN TIDE LEVEL                            MTL    =  0.193
     MEAN LOW WATER                             MLW    =  0.080
     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 4 1975                                   0.516    0.210
     NO 1 1975                                   2.445    2.139
     NO 2 1975                                   2.472    2.166
     NO 3 1975                                   0.994    0.688
     4423 F                                      4.203    3.897


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

                                                                                
Station ID: 8724423                         PUBLICATION DATE:  02/05/2004
Name:       SADDLEBUNCH CHANNEL NO. 5                         
            FL
NOAA Chart: 11442                           Latitude:   24° 36.7' N (  24.61170)
USGS Quad:  SADDLEBUNCH KEYS                Longitude:  81° 37.4' W ( -81.62330)


                             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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