Bench Mark Sheet for 8724168, NO NAME 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Superseded Epoch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Small blue map location marker Unpublished bench mark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: 8724168                         PUBLICATION DATE:  03/09/2004
Name:       NO NAME KEY                                       
            FL
NOAA Chart: 11445                           Latitude:   24° 41.9' N (  24.69830)
USGS Quad:  BIG PINE KEY                    Longitude:  81° 19.1' W ( -81.31830)


To reach the tidal bench marks from the intersection of U.S. Highway 1 and
County Road 940 (Key Deer Boulevard), proceed 2.7 km (1.7 mi) NW on County Road
940 to Watson Boulevard, thrn turn left and proceed east on Watson Boulevard for
5.6 km (3.5 mi), veering left at the fork to continue on State Route 4A, to its
end on No Name Key.  The bench marks are located along Watson Boulevard, and
along a dirt road leading north from Watson Boulevard.  The tide gage and staff
were located on a pier at the end of Watson Boulevard.


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


                 PRIMARY BENCH MARK STAMPING:  NO 1 1935
                         DESIGNATION:          872 4168 TIDAL 1 1935

MONUMENTATION:           Tidal Station disk                    VM#:         6386
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  AA0247
SETTING CLASSIFICATION:  Concrete post                         OPUS PID:        
LATITUDE:   24° 41.9' N (  24.69830)          LONGITUDE:  81° 19.1' W ( -81.31830)


The primary bench mark is a disk near an abandoned concrete water tank along the
dirt road, set in the top of a 0.3 x 0.3 m (1 x 1 ft) concrete post, 32 m (105
ft) north of the centerline of the boulevard, 17.4 m (57.0 ft) NE of bench mark
NO 1 1973, 9.88 m (32.4 ft) north of the north side of an abandoned concrete
slab, 5.09 m (16.7 ft) west of the centerline of the dirt road, 2.29 m (7.5 ft)
west of the SE corner of the water tank, 0.30 m (1.0 ft) south of the south side
of the water tank, and at ground level.

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

                                                                                
Station ID: 8724168                         PUBLICATION DATE:  03/09/2004
Name:       NO NAME KEY                                       
            FL
NOAA Chart: 11445                           Latitude:   24° 41.9' N (  24.69830)
USGS Quad:  BIG PINE KEY                    Longitude:  81° 19.1' W ( -81.31830)


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


                         BENCH MARK STAMPING:  NO 3 1935
                         DESIGNATION:          872 4168 TIDAL 3

MONUMENTATION:           Tidal Station disk                    VM#:         6387
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  AA0249
SETTING CLASSIFICATION:  Concrete post                         OPUS PID:        
LATITUDE:   24° 41.9' N (  24.69830)          LONGITUDE:  81° 19.1' W ( -81.31830)


The bench mark is a disk set in the top of a 0.3 x 0.3 m (1 x 1 ft) concrete
post, 29.81 m (97.8 ft) WSW of the northernmost concrete post which supports the
guard rail at the east end of the boulevard, 25.66 m (84.2 ft) SW of the SE
corner of a concrete slab, 21.15 m (69.4 ft) SSW of bench mark NO 1 1973, 5.49 m
(18.0 ft) south of the centerline of the boulevard, and at ground level.



                         BENCH MARK STAMPING:  NO 1 1973
                         DESIGNATION:          872 4168 TIDAL 1 1973

MONUMENTATION:           Tidal Station disk                    VM#:         6388
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  AA0899
SETTING CLASSIFICATION:  Concrete post                         OPUS PID:        
LATITUDE:   24° 41.9' N (  24.69830)          LONGITUDE:  81° 19.1' W ( -81.31830)


The bench mark is a disk set in the top of a concrete post, 21.15 m (69.4 ft)
NNE and across the boulevard from bench mark NO 3 1935, 17 m (57 ft) SW of bench
mark NO 1 1935, 16 m (54 ft) north of the centerline of the boulevard, 12.56 m
(41.2 ft) west of the centerline of the dirt road, 9 m (30 ft) WSW of the SE
corner of a concrete slab, 0.9 m (3 ft) south of the south side of the concrete
slab, and at ground level.

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

                                                                                
Station ID: 8724168                         PUBLICATION DATE:  03/09/2004
Name:       NO NAME KEY                                       
            FL
NOAA Chart: 11445                           Latitude:   24° 41.9' N (  24.69830)
USGS Quad:  BIG PINE KEY                    Longitude:  81° 19.1' W ( -81.31830)


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


                         BENCH MARK STAMPING:  4168 D 1982
                         DESIGNATION:          872 4168 D  TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         6389
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  AA0900
SETTING CLASSIFICATION:  Rock outcrop                          OPUS PID:        
LATITUDE:   24° 41.9' N (  24.69830)          LONGITUDE:  81° 19.1' W ( -81.31830)


The bench mark is a disk set in the top of a rock outcrop, 0.3 km (0.2 mi) west
of the east end of the boulevard, 10.45 m (34.3 ft) south of the centerline of
the boulevard, 7.62 m (25.0 ft) west of the centerline of a dirt road, and at
road level.



                         BENCH MARK STAMPING:  4168 E 1982
                         DESIGNATION:          872 4168 E TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         6390
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  AA0901
SETTING CLASSIFICATION:  Rock outcrop                          OPUS PID:        
LATITUDE:   24° 41.9' N (  24.69830)          LONGITUDE:  81° 19.1' W ( -81.31830)


The bench mark is a disk set in the top of a rock outcrop at the north edge of a
line of trees paralleling the boulevard, 0.5 km (0.3 mi) west of the east end of
the boulevard, 194.55 m (638.3 ft) west of bench mark 4168 D 1982, 8.32 m (27.3
ft) south of the centerline of the boulevard, 4.69 m (15.4 ft) north of a tree
with a witness sign attached, and 0.3 m (1 ft) below road level.

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

                                                                                
Station ID: 8724168                         PUBLICATION DATE:  03/09/2004
Name:       NO NAME KEY                                       
            FL
NOAA Chart: 11445                           Latitude:   24° 41.9' N (  24.69830)
USGS Quad:  BIG PINE KEY                    Longitude:  81° 19.1' W ( -81.31830)


                            T I D A L   D A T U M S 


Tidal datums at NO NAME KEY based on:

     LENGTH OF SERIES:      3 MONTHS
     TIME PERIOD:           December 1973 - February 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:

     North American Vertical Datum              NAVD88 =  0.418
     MEAN HIGHER HIGH WATER                     MHHW   =  0.345
     MEAN HIGH WATER                            MHW    =  0.266
     MEAN SEA LEVEL                             MSL    =  0.185
     MEAN TIDE LEVEL                            MTL    =  0.162
     MEAN LOW WATER                             MLW    =  0.058
     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 1935                                   0.965    0.699
     NO 3 1935                                   1.059    0.793
     NO 1 1973                                   0.950    0.684
     4168 D 1982                                 1.521    1.255
     4168 E 1982                                 1.487    1.221


Foot Notes:

Bench marks 4168 D 1982 and 4168 E 1982 are based on one differential leveling
connection and do not meet the quality control standards of the NOS. Therefore,
caution should be used when deriving elevations for these marks.

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

                                                                                
Station ID: 8724168                         PUBLICATION DATE:  03/09/2004
Name:       NO NAME KEY                                       
            FL
NOAA Chart: 11445                           Latitude:   24° 41.9' N (  24.69830)
USGS Quad:  BIG PINE KEY                    Longitude:  81° 19.1' W ( -81.31830)


                             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.

Return to Top
Products available at 8724168 NO NAME KEY, FL