U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  7

                                                                                
Station ID: 8724332                         PUBLICATION DATE:  06/09/2003
Name:       CUDJOE KEY PIRATES COVE                           
            FL
NOAA Chart: 11434                           Latitude:   24° 39.7' N (  24.66170)
USGS Quad:  SUGARLOAF KEY                   Longitude:  81° 30.9' W ( -81.51500)


To reach the tidal bench marks from the Catholic Church in Key West, proceed
31.7 km (19.7 mi) NE along U.S. Highway 1 to the east end of the New Bow Channel
Bridge at Cudjoe Key.  The bench marks are located along U.S. Highway 1.  The
tide gage and staff were located on the New Bow Channel Bridge.


                         T I D A L   B E N C H   M A R K S
                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  7

                                                                                
Station ID: 8724332                         PUBLICATION DATE:  06/09/2003
Name:       CUDJOE KEY PIRATES COVE                           
            FL
NOAA Chart: 11434                           Latitude:   24° 39.7' N (  24.66170)
USGS Quad:  SUGARLOAF KEY                   Longitude:  81° 30.9' W ( -81.51500)


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


                 PRIMARY BENCH MARK STAMPING:  M 70 RESET 1938
                         DESIGNATION:          M 70 RESET

MONUMENTATION:           Bench Mark disk                       VM#:         6959
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  AA0159
SETTING CLASSIFICATION:  Concrete wing wall                    OPUS PID:        
LATITUDE:   24° 39.7' N (  24.66170)          LONGITUDE:  81° 30.9' W ( -81.51500)


The primary bench mark is a disk set on the top of the south concrete wingwall
at the east end of Bow Channel Viaduct (bridge No. 9A), 5 m (15 ft) south of the
centerline of U.S. Highway 1, and 1 m (3 ft) below highway level.



                         BENCH MARK STAMPING:  4332 F 1982
                         DESIGNATION:          872 4332 F TIDAL

MONUMENTATION:           Bench Mark disk                       VM#:         6955
AGENCY:                  Florida Department of Transportation
                         (FLDT)                                IDB PID#:  AA0725
SETTING CLASSIFICATION:  Concrete bridge guardrail             OPUS PID:        
LATITUDE:   24° 39.7' N (  24.66170)          LONGITUDE:  81° 30.9' W ( -81.51500)


The bench mark is a disk set flush in the top of the NE end of the concrete
guardrail for the new Bow Channel Bridge, 5.85 m (19.2 ft) north of the
centerline of the highway, 3 m (10 ft) west of the NE end of the guardrail, and
0.91 m (3.0 ft) above the level of the highway.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  7

                                                                                
Station ID: 8724332                         PUBLICATION DATE:  06/09/2003
Name:       CUDJOE KEY PIRATES COVE                           
            FL
NOAA Chart: 11434                           Latitude:   24° 39.7' N (  24.66170)
USGS Quad:  SUGARLOAF KEY                   Longitude:  81° 30.9' W ( -81.51500)


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


                         BENCH MARK STAMPING:  4332 G 1982
                         DESIGNATION:          872 4332 G TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         6956
AGENCY:                  National Ocean Service (NOS)          IDB PID#:  AA0724
SETTING CLASSIFICATION:  Concrete bridge guardrail             OPUS PID:        
LATITUDE:   24° 39.7' N (  24.66170)          LONGITUDE:  81° 30.9' W ( -81.51500)


The bench mark is a disk set flush in the top of the SE concrete guardrail, 5.85
m (19.2 ft) south of the centerline of the highway, 0.21 m (0.7 ft) west of the
SE corner of the guardrail, and 0.91 m (3.0 ft) above the level of the highway.



                         BENCH MARK STAMPING:  4332 H 1982
                         DESIGNATION:          872 4332 H TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         6957
AGENCY:                  National Ocean Service (NOS)          IDB PID#:  AA0723
SETTING CLASSIFICATION:  Concrete wing wall                    OPUS PID:        
LATITUDE:   24° 39.7' N (  24.66170)          LONGITUDE:  81° 30.9' W ( -81.51500)


The bench mark is a disk set in the wingwall that supports the main waterline
for the Keys, 7.19 m (23.6 ft) SSW of the centerline of the New Bow Channel
Bridge, 3.32 m (10.9 ft) WSW of bench mark 4332 G 1982, 1.10 m (3.6 ft) SSW of
the SE corner of the concrete rail, 0.14 m (0.45 ft) NNE of the south end of the
wingwall, and 0.43 m (1.4 ft) below the level of the highway.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  7

                                                                                
Station ID: 8724332                         PUBLICATION DATE:  06/09/2003
Name:       CUDJOE KEY PIRATES COVE                           
            FL
NOAA Chart: 11434                           Latitude:   24° 39.7' N (  24.66170)
USGS Quad:  SUGARLOAF KEY                   Longitude:  81° 30.9' W ( -81.51500)


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


                         BENCH MARK STAMPING:  G 272 1966
                         DESIGNATION:          G 272

MONUMENTATION:           Bench Mark disk                       VM#:         6960
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  AA0153
SETTING CLASSIFICATION:  Concrete wing wall                    OPUS PID:        
LATITUDE:   24° 39.6' N (  24.66000)          LONGITUDE:  81° 31.1' W ( -81.51830)


The bench mark is a disk set in the top of a south concrete wingwall at the west
end of Bow Channel Viaduct (bridge No. 9A) at the turn in the wingwall, 20 m (64
ft) south of the centerline of U.S. Highway 1, 3 m (11 ft) east of the west end
of a wingwall, and 3 m (10 ft) below highway level.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  5 of  7

                                                                                
Station ID: 8724332                         PUBLICATION DATE:  06/09/2003
Name:       CUDJOE KEY PIRATES COVE                           
            FL
NOAA Chart: 11434                           Latitude:   24° 39.7' N (  24.66170)
USGS Quad:  SUGARLOAF KEY                   Longitude:  81° 30.9' W ( -81.51500)


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


                         BENCH MARK STAMPING:  T 328 1970
                         DESIGNATION:          T 328

MONUMENTATION:           Bench Mark disk                       VM#:         6962
AGENCY:                  National Geodetic Survey (NGS)        IDB PID#:  AA0158
SETTING CLASSIFICATION:  Concrete wing wall                    OPUS PID:        
LATITUDE:   24° 39.7' N (  24.66170)          LONGITUDE:  81° 30.9' W ( -81.51500)


The bench mark is a disk set flush in the top of the south concrete wingwall of
the Bow Channel Viaduct, 20 m (67 ft) south of the centerline of Route 1, 17.59
m (57.7 ft) SE of bench mark M 70 RESET 1938, and 6 m (20 ft) west of the east
end of the wingwall, and 3 m (10 ft) below highway level.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  6 of  7

                                                                                
Station ID: 8724332                         PUBLICATION DATE:  06/09/2003
Name:       CUDJOE KEY PIRATES COVE                           
            FL
NOAA Chart: 11434                           Latitude:   24° 39.7' N (  24.66170)
USGS Quad:  SUGARLOAF KEY                   Longitude:  81° 30.9' W ( -81.51500)


                            T I D A L   D A T U M S 


Tidal datums at CUDJOE KEY PIRATES COVE based on:

     LENGTH OF SERIES:      1 YEAR
     TIME PERIOD:           January 1971 - December 1971
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  8724580 KEY WEST


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

     HIGHEST OBSERVED WATER LEVEL (11/04/1971)         =  0.703
     MEAN HIGHER HIGH WATER                     MHHW   =  0.427
     North American Vertical Datum              NAVD88 =  0.370
     MEAN HIGH WATER                            MHW    =  0.357
     MEAN TIDE LEVEL                            MTL    =  0.207
     MEAN SEA LEVEL                             MSL    =  0.190
     MEAN LOW WATER                             MLW    =  0.057
     MEAN LOWER LOW WATER                       MLLW   =  0.000
     LOWEST  OBSERVED WATER LEVEL (08/31/1974)         = -0.266

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     M 70 RESET 1938                             3.868    3.511
     4332 F 1982                                 5.063    4.706
     4332 G 1982                                 5.046    4.689
     4332 H 1982                                 3.796    3.439
     G 272 1966                                  0.962    0.605
     T 328 1970                                  0.971    0.614


Foot Notes:

Bench marks 4332 F 1982, 4332 G 1982, 4332 H 1982, and G 272 1966 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  7 of  7

                                                                                
Station ID: 8724332                         PUBLICATION DATE:  06/09/2003
Name:       CUDJOE KEY PIRATES COVE                           
            FL
NOAA Chart: 11434                           Latitude:   24° 39.7' N (  24.66170)
USGS Quad:  SUGARLOAF KEY                   Longitude:  81° 30.9' W ( -81.51500)


                             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.