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

                                                                                
Station ID: 8723747                         PUBLICATION DATE:  04/01/2004
Name:       TAVERNIER HAWK CHANNEL                            
            FL
NOAA Chart: 11463                           Latitude:   25°  0.3' N (  25.00500)
USGS Quad:  TAVERNIER                       Longitude:  80° 31.0' W ( -80.51670)


To reach the tidal bench marks from the post office at Tavernier, proceed about
0.6 km (0.4 mi) SW on U.S. Highway 1 to the intersection of U.S. Highway 1 and
Lowe Street, then 0.5 km (0.3 mi) south along Lowe Street to Point Lowe.  The
bench marks are located near the boat dock, south of the road, and adjacent to
the intersection of U.S. Highway 1 and Ocean Boulevard.  The tide gage and staff
were located on the boat dock at the boat slip at the end of Lowe Street.


                         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: 8723747                         PUBLICATION DATE:  04/01/2004
Name:       TAVERNIER HAWK CHANNEL                            
            FL
NOAA Chart: 11463                           Latitude:   25°  0.3' N (  25.00500)
USGS Quad:  TAVERNIER                       Longitude:  80° 31.0' W ( -80.51670)


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


                 PRIMARY BENCH MARK STAMPING:  LOWE RM 1 1934
                         DESIGNATION:          LOWE RM 1

MONUMENTATION:           Reference Mark disk                   VM#:         5999
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  AC0440
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   25°  0.2' N (  25.00330)          LONGITUDE:  80° 31.1' W ( -80.51830)


The primary bench mark is a disk set in the top of a 0.30 m x 0.30 m (1.0 ft x
1.0 ft) concrete post, located near Dressing Point SE of Tavernier, 0.2 km (0.1
mi) south of the boat dock, 27 m (88 ft) NW of the edge of the water, and 0.15 m
(0.5 ft) above the level of a coral rock.



                         BENCH MARK STAMPING:  NO 1 1935
                         DESIGNATION:          872 3747 TIDAL 1

MONUMENTATION:           Tidal Station disk                    VM#:         6000
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  AC0441
SETTING CLASSIFICATION:  Concrete filled terra cotta pipe      OPUS PID:        
LATITUDE:   25°  0.2' N (  25.00330)          LONGITUDE:  80° 31.0' W ( -80.51670)


The bench mark is a disk set in the top of a 0.15 m (0.5 ft) diameter terra
cotta pipe filled with concrete, located near Point Lowe in the vicinity of the
boat dock, 20 m (67 ft) south of the centerline of Lowe Street, 14.69 m (48.2
ft) NW of a 2-inch iron pipe which supports a gas yard light, 12.65 m (41.5 ft)
south of a power pole, 11.13 m (36.5 ft) east of the centerline of the driveway
to the Dressing residence, 5.52 m (18.1 ft) north of the NE corner of the house,
0.3 m (1 ft) west of the extended east wall of the house, level with the street,
and 0.18 m (0.6 ft) below ground level.

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

                                                                                
Station ID: 8723747                         PUBLICATION DATE:  04/01/2004
Name:       TAVERNIER HAWK CHANNEL                            
            FL
NOAA Chart: 11463                           Latitude:   25°  0.3' N (  25.00500)
USGS Quad:  TAVERNIER                       Longitude:  80° 31.0' W ( -80.51670)


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


                         BENCH MARK STAMPING:  U 327 1970
                         DESIGNATION:          U 327

MONUMENTATION:           Bench Mark disk                       VM#:         6001
AGENCY:                  National Geodetic Survey (NGS)        IDB PID#:  AC0444
SETTING CLASSIFICATION:  Boulder                               OPUS PID:        
LATITUDE:   25°  0.2' N (  25.00330)          LONGITUDE:  80° 31.0' W ( -80.51670)


The bench mark is a disk set in the top of a large coral boulder, located near
Point Lowe at the SW corner of the boat, 14 m (45 ft) NE of the north corner of
a guard rail at the end of the dock, 12 m (39 ft) east of a light pole, 0.30 m
(1.0 ft) north of a wooden guard rail, about 1 m (2 ft) above the level of Lowe
Street, and 0.46 m (1.5 ft) above the level of the dock.

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

                                                                                
Station ID: 8723747                         PUBLICATION DATE:  04/01/2004
Name:       TAVERNIER HAWK CHANNEL                            
            FL
NOAA Chart: 11463                           Latitude:   25°  0.3' N (  25.00500)
USGS Quad:  TAVERNIER                       Longitude:  80° 31.0' W ( -80.51670)


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


                         BENCH MARK STAMPING:  V 327 1970
                         DESIGNATION:          V 327

MONUMENTATION:           Bench Mark disk                       VM#:         6002
AGENCY:                  National Geodetic Survey (NGS)        IDB PID#:  AC0443
SETTING CLASSIFICATION:  Boulder                               OPUS PID:        
LATITUDE:   25°  0.2' N (  25.00330)          LONGITUDE:  80° 31.0' W ( -80.51670)


The bench mark is a disk set in the top of a 1 m (4 ft) coral boulder, located
near Point Lowe in the vicinity of the boat dock, 45 m (147 ft) south of the
south end of a metal guard rail at the end of Lowe Street, 39 m (127 ft) SE of
the SE corner of a two-story house, 0.30 m (1.0 ft) above ground, and about
level with Lowe Street.



                         BENCH MARK STAMPING:  3747 F 1982
                         DESIGNATION:          872 3747 F TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         6003
AGENCY:                  Florida Department of Natural Resources
                         (FLDNR)                               IDB PID#:  AC3363
SETTING CLASSIFICATION:  Concrete foundation                   OPUS PID:        
LATITUDE:   25°  0.3' N (  25.00500)          LONGITUDE:  80° 31.3' W ( -80.52170)


The bench mark is a disk set in the top of the west corner of a 6 m x 3 m (20 ft
x 11 ft) concrete foundation for the water pipe line, located near the
intersection of U.S. Highway 1 and Ocean Boulevard, 22 m (72 ft) NW of the
intersection of U.S. Highway 1 and Ocean Boulevard, 2.53 m (8.3 ft) SSE of the
curb of the southbound lane of U.S. Highway 1, SE of McDonalds restaurant, and
about level with the ground.

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

                                                                                
Station ID: 8723747                         PUBLICATION DATE:  04/01/2004
Name:       TAVERNIER HAWK CHANNEL                            
            FL
NOAA Chart: 11463                           Latitude:   25°  0.3' N (  25.00500)
USGS Quad:  TAVERNIER                       Longitude:  80° 31.0' W ( -80.51670)


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


                         BENCH MARK STAMPING:  3747 G 1982
                         DESIGNATION:          872 3747 G TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         6004
AGENCY:                  Florida Department of Natural Resources
                         (FLDNR)                               IDB PID#:  AC3364
SETTING CLASSIFICATION:  Concrete foundation                   OPUS PID:        
LATITUDE:   25°  0.3' N (  25.00500)          LONGITUDE:  80° 31.0' W ( -80.51670)


The bench mark is a disk set in the top of the concrete foundation for a power
pole, located near the intersection of U.S. Highway 1 and Ocean Boulevard, 113 m
(370 ft) SW of the centerline of Ocean Boulevard, 25.48 m (83.6 ft) SE of the SE
side of U.S. Highway 1, south of McDonalds restaurant, and 0.46 m (1.5 ft) above
the level of the ground.

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

                                                                                
Station ID: 8723747                         PUBLICATION DATE:  04/01/2004
Name:       TAVERNIER HAWK CHANNEL                            
            FL
NOAA Chart: 11463                           Latitude:   25°  0.3' N (  25.00500)
USGS Quad:  TAVERNIER                       Longitude:  80° 31.0' W ( -80.51670)


                            T I D A L   D A T U M S 


Tidal datums at TAVERNIER HAWK CHANNEL 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 (11/02/1971)         =  0.973
     MEAN HIGHER HIGH WATER                     MHHW   =  0.716
     MEAN HIGH WATER                            MHW    =  0.681
     North American Vertical Datum              NAVD88 =  0.638
     MEAN SEA LEVEL                             MSL    =  0.376
     MEAN TIDE LEVEL                            MTL    =  0.370
     MEAN LOW WATER                             MLW    =  0.058
     MEAN LOWER LOW WATER                       MLLW   =  0.000
     LOWEST  OBSERVED WATER LEVEL (02/10/1971)         = -0.438

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     LOWE RM 1 1934                              0.880    0.199
     NO 1 1935                                   1.248    0.567
     U 327 1970                                  1.808    1.127
     V 327 1970                                  1.287    0.606
     3747 F 1982                                 2.838    2.157
     3747 G 1982                                 1.368    0.687


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

                                                                                
Station ID: 8723747                         PUBLICATION DATE:  04/01/2004
Name:       TAVERNIER HAWK CHANNEL                            
            FL
NOAA Chart: 11463                           Latitude:   25°  0.3' N (  25.00500)
USGS Quad:  TAVERNIER                       Longitude:  80° 31.0' W ( -80.51670)


                             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.