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

                                                   PUBLICATION DATE:  06/27/2001
Station ID: 8723214                                SUPERCEDED DATE:   04/21/2003
Name:       VIRGINIA KEY, BISCAYNE BAY                        
            FLORIDA
NOAA Chart: 11465                                  Latitude:         25° 43.9' N
USGS Quad:  KEY BISCAYNE                           Longitude:        80°  9.7' W


To reach the tidal bench marks from the intersection of U.S. Route 1 and
Rickenbacker Causeway, proceed  5 km (3 mi) east on Rickenbacker Causeway to the
entrance of the Rosenstiel School of Marine and Atmospheric  Science (Univ. of
Miami).  The bench marks are located in the vicinity of the concrete pier and on
the School grounds.  The tide station is located at the outer end of the
concrete pier.


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


                 PRIMARY BENCH MARK STAMPING:  3214 B 1994
                         DESIGNATION:          872 3214 B

MONUMENTATION:           Tidal Station disk                        VM#:    12600
AGENCY:                  National Ocean Service (NOS)              PID#:  AH5251
SETTING CLASSIFICATION:  Stainless steel rod


The primary bench mark is a disk located at the shore end of the pier at the
Rosenstiel School of Marine and Atmospheric Science, 38.70 m (127.0 ft) NE of
the SE corner of the Alfred C. Glassell Jr. Lab, 7.71 m (25.3 ft) SE of the west
corner of a 8.99 m x 7.16 m (29.5 ft x 23.5 ft) satellite dish foundation, 7.44
m (24.4 ft) NW of the west corner of a 1.19 m x 1.19 m (3.9 ft x 3.9 ft)
satellite dish foundation, and 2.95 m (9.6 ft) ENE of the centerline of the
concrete pier.  The bench mark is 6 cm (0.2 ft) below ground level, crimped to a
stainless steel rod driven 15.8 m (52 ft) to refusal, and encased in a 6-inch
PVC pipe with concrete kickblock.



                         BENCH MARK STAMPING:  3214 A 1994
                         DESIGNATION:          872 3214 A

MONUMENTATION:           Tidal Station disk                        VM#:    12599
AGENCY:                  National Ocean Service (NOS)              PID#:  AH5252
SETTING CLASSIFICATION:  Concrete pier


The bench mark is a disk set flush on the concrete pier of the Rosenstiel School
between a bollard and a 6x6-inch wooden bumper, 24.60 m (80.7 ft) south of a
lifting boom, 4.15 m (13.6 ft) west of a Rohn tower, and 0.15 m (0.5 ft) east of
the west face of the pier.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  7

                                                   PUBLICATION DATE:  06/27/2001
Station ID: 8723214                                SUPERCEDED DATE:   04/21/2003
Name:       VIRGINIA KEY, BISCAYNE BAY                        
            FLORIDA
NOAA Chart: 11465                                  Latitude:         25° 43.9' N
USGS Quad:  KEY BISCAYNE                           Longitude:        80°  9.7' W


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


                         BENCH MARK STAMPING:  3214 C 1994
                         DESIGNATION:          872 3214 C

MONUMENTATION:           Tidal Station disk                        VM#:    12601
AGENCY:                  National Ocean Service (NOS)              PID#:  AH5250
SETTING CLASSIFICATION:  Concrete step


The bench mark is a disk set flush in a concrete step at the entrance to the
Alfred C. Glassell Jr. Lab, 28.10 m (92.2 ft) SW of the SE corner of the
Grosvenor Building, 6.95 m (22.8 ft) east of the NW corner of the lab, and 0.27
m (0.9 ft) SW of the NE corner of the first step of the north entrance to the
lab.



                         BENCH MARK STAMPING:  3214 D 1994
                         DESIGNATION:          872 3214  D

MONUMENTATION:           Tidal Station disk                        VM#:    12602
AGENCY:                  National Ocean Service (NOS)              PID#:  AH5248
SETTING CLASSIFICATION:  Concrete step


The bench mark a disk is set flush in a concrete step of the NW entrance to the
Operations Building, 24.60 m (80.7 ft) NW of the east corner of the Grosvenor
Building, 20.18 m (66.2 ft) west of the NW corner of the Grosvenor Building, and
0.18 m (0.6 ft) east of the east face of the first step to the NE entrance.

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

                                                   PUBLICATION DATE:  06/27/2001
Station ID: 8723214                                SUPERCEDED DATE:   04/21/2003
Name:       VIRGINIA KEY, BISCAYNE BAY                        
            FLORIDA
NOAA Chart: 11465                                  Latitude:         25° 43.9' N
USGS Quad:  KEY BISCAYNE                           Longitude:        80°  9.7' W


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


                         BENCH MARK STAMPING:  3214 E 1994
                         DESIGNATION:          872 3214 E

MONUMENTATION:           Tidal Station disk                        VM#:    12603
AGENCY:                  National Ocean Service (NOS)              PID#:  DG7157
SETTING CLASSIFICATION:  Stainless steel rod


The bench mark is a disk set in the middle of three palm trees in a grassy
median in the NW parking area at the Rosenstiel School, 19.99 m (65.6 ft) NE of
the NW corner of the Gilbert H. Grosvenor lab, 6.10 m (20.0 ft) north of the
centerline of the road leading into school property, and 1.25 m (4.1 ft) NW of a
3-inch diameter light pole.  The bench mark is at ground level, crimped to a
stainless steel rod driven 18.3 m (60 ft) to refusal, and encased in a 6-inch
PVC pipe with concrete kickblock.



                         BENCH MARK STAMPING:  3214 F 1997
                         DESIGNATION:          872 3214 F

MONUMENTATION:           Flange-encased Rod                        VM#:    13456
AGENCY:                  National Ocean Service (NOS)              PID#:  AH5246
SETTING CLASSIFICATION:  Stainless steel rod in sleeve


The bench mark is a flange-encased rod located SE of the main entrance to
Rosenstiel School of Marine and Atmospheric Science, 79.00 m (259.2 ft) SE of
the NW end of a concrete guardrail, 12.95 m (42.5 ft) north of the NW corner of
the concrete building housing public rest rooms, 9.60 m (31.5 ft) SW of the
eastbound lane of Rickenbacker Causeway, and 1.19 m (3.9 ft) SW of a 1 m (3 ft)
concrete guardrail.  The datum point is the top of a stainless steel rod driven
12.2 m (40 ft) to refusal, encased in a no-tox grease sleeve inside a 5-inch PVC
pipe and NOS logo cap.

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

                                                   PUBLICATION DATE:  06/27/2001
Station ID: 8723214                                SUPERCEDED DATE:   04/21/2003
Name:       VIRGINIA KEY, BISCAYNE BAY                        
            FLORIDA
NOAA Chart: 11465                                  Latitude:         25° 43.9' N
USGS Quad:  KEY BISCAYNE                           Longitude:        80°  9.7' W


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


                         BENCH MARK STAMPING:  3214 G 1998
                         DESIGNATION:          872 3214 G

MONUMENTATION:           Tidal Station disk                        VM#:    13894
AGENCY:                  National Ocean Service (NOS)              PID#:  AH5247
SETTING CLASSIFICATION:  Concrete wing wall


The bench mark is a disk set flush in the concrete wing wall on the NW side the
Rickenbacker Causeway bridge over Bear Cut, next to the property of the
Rosenstiel School of Marine and Atmospheric Sciences, 17.12 m (56.2 ft) NE of
the corner of the chainlink fence at the NE corner of the school property, 8.85
m (29.0 ft) SSW of the SW metal rail of the bridge, 2.85 m (9.4 ft) NW of a
chainlink fence that runs into the bridge, and 0.35 m (1.2 ft) SE of the end of
the wing wall.



                         BENCH MARK STAMPING:  MI 6 RESET
                         DESIGNATION:          872 3214 MI 6 RESET

MONUMENTATION:           See descriptive text                      VM#:    16188
AGENCY:                  Unknown                                   PID#:  AC2151
SETTING CLASSIFICATION:  Sidewalk


The bench mark is a nail and washer set in the top of the NW end of the SW
concrete guard rail to the Bear Cut bridge over Biscayne Bay, 0.30 m (1.0 ft) SW
of the SW curb of the bridge, 0.30 m (1.0 ft) SE of the NW end of the base, and
0.30 m (1.0 ft) above the level of the roadway.

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

                                                   PUBLICATION DATE:  06/27/2001
Station ID: 8723214                                SUPERCEDED DATE:   04/21/2003
Name:       VIRGINIA KEY, BISCAYNE BAY                        
            FLORIDA
NOAA Chart: 11465                                  Latitude:         25° 43.9' N
USGS Quad:  KEY BISCAYNE                           Longitude:        80°  9.7' W


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


                         BENCH MARK STAMPING:  U 313 1970
                         DESIGNATION:          U 313

MONUMENTATION:           Bench Mark disk                           VM#:    16189
AGENCY:                  National Geodetic Survey (NGS)            PID#:  AC2154
SETTING CLASSIFICATION:  Concrete base


The bench mark is a disk set in the top of the NW corner of the top step of the
concrete base for two flagpoles at the City of Miami Marine Stadium along
Rickenbacker Causeway, between the exit and entrance drive to the stadium, 0.27
m (0.9 ft) SE of the NW corner of the top step of the base, and 0.46 m (1.5 ft)
above ground level.

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

                                                   PUBLICATION DATE:  06/27/2001
Station ID: 8723214                                SUPERCEDED DATE:   04/21/2003
Name:       VIRGINIA KEY, BISCAYNE BAY                        
            FLORIDA
NOAA Chart: 11465                                  Latitude:         25° 43.9' N
USGS Quad:  KEY BISCAYNE                           Longitude:        80°  9.7' W


                            T I D A L   D A T U M S 


Tidal datums at VIRGINIA KEY, BISCAYNE BAY based on:

     LENGTH OF SERIES:      69 MONTHS
     TIME PERIOD:           February 1994 - December 1999
     TIDAL EPOCH:           1960-1978
     CONTROL TIDE STATION:  8724580 KEY WEST


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

     HIGHEST OBSERVED WATER LEVEL (11/15/1994)         =  1.338
     MEAN HIGHER HIGH WATER                     MHHW   =  0.701
     North American Vertical Datum              NAVD88 =  0.683
     MEAN HIGH WATER                            MHW    =  0.679
     MEAN TIDE LEVEL                            MTL    =  0.359
     MEAN SEA LEVEL                             MSL    =  0.352
     MEAN LOW WATER                             MLW    =  0.038
     MEAN LOWER LOW WATER                       MLLW   =  0.000
     LOWEST  OBSERVED WATER LEVEL (03/29/1994)         = -0.318

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     3214 B 1994                                 1.985    1.306
     3214 A 1994                                 2.090    1.411
     3214 C 1994                                 1.983    1.304
     3214 D 1994                                 2.163    1.484
     3214 E 1994                                 2.039    1.360
     3214 F 1997                                 2.559    1.880
     3214 G 1998                                 1.724    1.045
     MI 6 RESET                                  3.576    2.897
     U 313 1970                                  2.473    1.794


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

                                                   PUBLICATION DATE:  06/27/2001
Station ID: 8723214                                SUPERCEDED DATE:   04/21/2003
Name:       VIRGINIA KEY, BISCAYNE BAY                        
            FLORIDA
NOAA Chart: 11465                                  Latitude:         25° 43.9' N
USGS Quad:  KEY BISCAYNE                           Longitude:        80°  9.7' W


                             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 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.