U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  8

                                                                                
Station ID: 8723534                         PUBLICATION DATE:  04/29/2004
Name:       CARD SOUND BRIDGE                                 
            FL
NOAA Chart: 11463                           Latitude:   25° 17.3' N (  25.28830)
USGS Quad:  CARD SOUND                      Longitude:  80° 22.2' W ( -80.37000)


To reach the tidal bench marks from the intersection of U.S. Highway 1 and Card
Sound Road in Florida City proceed SE on Card Sound Road for 19.5 km (12.1 mi)
to the Card Sound bridge.  The bench marks are located on the fishing pier
located underneath the bridge.  The tide gage and staff were located on a bridge
pile base on the west end of the west fishing pier under the 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  8

                                                                                
Station ID: 8723534                         PUBLICATION DATE:  04/29/2004
Name:       CARD SOUND BRIDGE                                 
            FL
NOAA Chart: 11463                           Latitude:   25° 17.3' N (  25.28830)
USGS Quad:  CARD SOUND                      Longitude:  80° 22.2' W ( -80.37000)


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


                 PRIMARY BENCH MARK STAMPING:  N 316 1970
                         DESIGNATION:          N 316

MONUMENTATION:           Bench Mark disk                       VM#:         5910
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  AC1125
SETTING CLASSIFICATION:  Concrete pier                         OPUS PID:        
LATITUDE:   25° 17.3' N (  25.28830)          LONGITUDE:  80° 22.2' W ( -80.37000)


The primary bench mark is a disk set flush in a drill hole in the south side of
the concrete fishing pier below the west end of the bridge, in the base of the
first pier west of the steps, 0.58 m (1.9 ft) north of the north face of the
south leg of the pier, and 0.46 m (1.5 ft) below pier level.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  8

                                                                                
Station ID: 8723534                         PUBLICATION DATE:  04/29/2004
Name:       CARD SOUND BRIDGE                                 
            FL
NOAA Chart: 11463                           Latitude:   25° 17.3' N (  25.28830)
USGS Quad:  CARD SOUND                      Longitude:  80° 22.2' W ( -80.37000)


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


                         BENCH MARK STAMPING:  P 316 1970
                         DESIGNATION:          P 316

MONUMENTATION:           Bench Mark disk                       VM#:         5911
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  AC1127
SETTING CLASSIFICATION:  Concrete pier                         OPUS PID:        
LATITUDE:   25° 17.3' N (  25.28830)          LONGITUDE:  80° 22.2' W ( -80.37000)


The bench mark is a disk set flush in a drill hole in the north side of the
concrete fishing pier below the west end of the bridge, in the base of the
fourth pier east of the steps, 0.55 m (1.8 ft) south of the south face of the
north leg of the pier, and 0.46 m (1.5 ft) below pier level.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  8

                                                                                
Station ID: 8723534                         PUBLICATION DATE:  04/29/2004
Name:       CARD SOUND BRIDGE                                 
            FL
NOAA Chart: 11463                           Latitude:   25° 17.3' N (  25.28830)
USGS Quad:  CARD SOUND                      Longitude:  80° 22.2' W ( -80.37000)


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


                         BENCH MARK STAMPING:  Q 316 1970
                         DESIGNATION:          Q 316

MONUMENTATION:           Bench Mark disk                       VM#:         5912
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  AC1124
SETTING CLASSIFICATION:  Concrete pier                         OPUS PID:        
LATITUDE:   25° 17.3' N (  25.28830)          LONGITUDE:  80° 22.2' W ( -80.37000)


The bench mark is a disk set flush in a drill hole on the south side of the
concrete fishing pier below the west end of the bridge, in the base of the
fourth pier east of the steps, 0.55 m (1.8 ft) north of the north face of the
south leg, and 0.46 m (1.5 ft) below pier level.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  5 of  8

                                                                                
Station ID: 8723534                         PUBLICATION DATE:  04/29/2004
Name:       CARD SOUND BRIDGE                                 
            FL
NOAA Chart: 11463                           Latitude:   25° 17.3' N (  25.28830)
USGS Quad:  CARD SOUND                      Longitude:  80° 22.2' W ( -80.37000)


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


                         BENCH MARK STAMPING:  R 316 1970
                         DESIGNATION:          R 316

MONUMENTATION:           Bench Mark disk                       VM#:         5913
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  AC1123
SETTING CLASSIFICATION:  Concrete pier                         OPUS PID:        
LATITUDE:   25° 17.3' N (  25.28830)          LONGITUDE:  80° 22.2' W ( -80.37000)


The bench mark is a disk set flush in a drill hole, on the north side if the
concrete fishing pier below the west end of the bridge, in the base of the sixth
pier east of the steps, 0.52 m (1.7 ft) south of the south face of the north leg
of the pier, and 0.46 m (1.5 ft) below pier level.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  6 of  8

                                                                                
Station ID: 8723534                         PUBLICATION DATE:  04/29/2004
Name:       CARD SOUND BRIDGE                                 
            FL
NOAA Chart: 11463                           Latitude:   25° 17.3' N (  25.28830)
USGS Quad:  CARD SOUND                      Longitude:  80° 22.2' W ( -80.37000)


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


                         BENCH MARK STAMPING:  S 316 1970
                         DESIGNATION:          S 316

MONUMENTATION:           Bench Mark disk                       VM#:         5914
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  AC1126
SETTING CLASSIFICATION:  Concrete pier                         OPUS PID:        
LATITUDE:   25° 17.3' N (  25.28830)          LONGITUDE:  80° 22.2' W ( -80.37000)


The bench mark is a disk set flush in a drill hole on the south side of the
concrete fishing pier below the west end of the bridge in the base of the eighth
pier east of the steps, 0.52 m (1.7 ft) north of the north face of the south leg
of the pier, and 0.46 m (1.5 ft) below pier level.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  7 of  8

                                                                                
Station ID: 8723534                         PUBLICATION DATE:  04/29/2004
Name:       CARD SOUND BRIDGE                                 
            FL
NOAA Chart: 11463                           Latitude:   25° 17.3' N (  25.28830)
USGS Quad:  CARD SOUND                      Longitude:  80° 22.2' W ( -80.37000)


                            T I D A L   D A T U M S 


Tidal datums at CARD SOUND BRIDGE based on:

     LENGTH OF SERIES:      1 YEAR
     TIME PERIOD:           May 1970 - April 1971
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  8723170 MIAMI BEACH (CITY PIER)


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

     HIGHEST OBSERVED WATER LEVEL (10/18/1970)         =  0.529
     North American Vertical Datum              NAVD88 =  0.325
     MEAN HIGHER HIGH WATER                     MHHW   =  0.193
     MEAN HIGH WATER                            MHW    =  0.180
     MEAN SEA LEVEL                             MSL    =  0.099
     MEAN TIDE LEVEL                            MTL    =  0.099
     MEAN LOW WATER                             MLW    =  0.018
     MEAN LOWER LOW WATER                       MLLW   =  0.000
     LOWEST  OBSERVED WATER LEVEL (02/08/1971)         = -0.248

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     N 316 1970                                  1.846    1.666
     P 316 1970                                  1.753    1.573
     Q 316 1970                                  1.763    1.583
     R 316 1970                                  1.752    1.572
     S 316 1970                                  1.767    1.587


                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  8 of  8

                                                                                
Station ID: 8723534                         PUBLICATION DATE:  04/29/2004
Name:       CARD SOUND BRIDGE                                 
            FL
NOAA Chart: 11463                           Latitude:   25° 17.3' N (  25.28830)
USGS Quad:  CARD SOUND                      Longitude:  80° 22.2' W ( -80.37000)


                             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.