U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  5

                                                                                
Station ID: 8727333                         PUBLICATION DATE:  04/01/2004
Name:       SHARK RIVER, CRYSTAL BAY                          
            FL
NOAA Chart: 11409                           Latitude:   28° 52.2' N (  28.87000)
USGS Quad:  OZELLO                          Longitude:  82° 43.4' W ( -82.72330)


To reach the tidal bench marks from the boat ramp at the west end of County Road
C-44 at Fort Island Beach west of Crystal River, proceed SW by boat for 4.9 km
(2.7 nm) to Mangrove Point.  The bench marks are located along Mangrove Point. 
The tide gage and staff were located on a platform out in the Shark River.


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


                 PRIMARY BENCH MARK STAMPING:  7333 A 1978
                         DESIGNATION:          872 7333 A

MONUMENTATION:           Tidal Station disk                    VM#:         7785
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   28° 52.2' N (  28.87000)          LONGITUDE:  82° 43.4' W ( -82.72330)


The primary bench mark is a disk located on the north shore of the island, 23 m
(75 ft) SW of the NE end of the island, 9 m (30 ft) from the edge of the seaward
grass line in the middle of a group of large dead trees, and 1 m (2 ft) north of
a witness post.  The bench mark is set 0.30 m (1.0 ft) above ground level,
crimped to the top of a copper-clad steel rod driven 6.1 m (20 ft) to refusal,
and encased in a PVC pipe and concrete kickblock.

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

                                                                                
Station ID: 8727333                         PUBLICATION DATE:  04/01/2004
Name:       SHARK RIVER, CRYSTAL BAY                          
            FL
NOAA Chart: 11409                           Latitude:   28° 52.2' N (  28.87000)
USGS Quad:  OZELLO                          Longitude:  82° 43.4' W ( -82.72330)


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


                         BENCH MARK STAMPING:  7333 B 1978
                         DESIGNATION:          872 7333 B

MONUMENTATION:           Tidal Station disk                    VM#:         7786
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   28° 52.2' N (  28.87000)          LONGITUDE:  82° 43.4' W ( -82.72330)


The bench mark is a disk located on the north shore of the island, 61 m (200 ft)
west of the NE end, 38 m (125 ft) west of bench mark 7333 A 1978, 9 m (30 ft)
south of the edge of the seaward grass line, and 1 m (2 ft) north of a witness
post.  The bench mark is set 0.55 m (1.8 ft) above ground level, crimped to the
top of a copper-clad steel rod driven 6.1 m (20 ft) to refusal, and encased in a
PVC pipe and concrete kickblock.



                         BENCH MARK STAMPING:  7333 C 1978
                         DESIGNATION:          872 7333 C

MONUMENTATION:           Tidal Station disk                    VM#:         7787
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   28° 52.2' N (  28.87000)          LONGITUDE:  82° 43.4' W ( -82.72330)


The bench mark is a disk located on the north shore of the island, on the
mangrove line, 101 m (330 ft) west of the NE end of the island, 40 m (130 ft)
west of bench mark 7333 B 1978, 3.05 m (10.0 ft) south of the edge of the
seaward grass line, and 0.46 m (1.5 ft) north of the witness post.  The bench
mark is set 0.46 m (1.5 ft) above ground level, crimped to the top of a
copper-clad steel rod driven 6.1 m (20 ft) to refusal, and encased in a PVC pipe
and concrete kickblock.

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

                                                                                
Station ID: 8727333                         PUBLICATION DATE:  04/01/2004
Name:       SHARK RIVER, CRYSTAL BAY                          
            FL
NOAA Chart: 11409                           Latitude:   28° 52.2' N (  28.87000)
USGS Quad:  OZELLO                          Longitude:  82° 43.4' W ( -82.72330)


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


                         BENCH MARK STAMPING:  7333 D 1978
                         DESIGNATION:          872 7333 D

MONUMENTATION:           Tidal Station disk                    VM#:         7788
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   28° 52.2' N (  28.87000)          LONGITUDE:  82° 43.4' W ( -82.72330)


The bench mark is a disk located on the north shore in the middle of the island,
on a small rounded point, 46 m (150 ft) west of bench mark 7333 C 1978, 5 m (15
ft) south of the edge of the seaward grass line on the mangrove line, 2 m (8 ft)
south of a large dead tree, and 1 m (2 ft) north of a witness post. The bench
mark is set 1 m (2 ft) above ground level, crimped to the top of a copper-clad
steel rod driven 6.1 m (20 ft) to refusal, and encased in a PVC pipe and
concrete kickblock.



                         BENCH MARK STAMPING:  7333 E 1978
                         DESIGNATION:          872 7333 E

MONUMENTATION:           Tidal Station disk                    VM#:         7789
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   28° 52.2' N (  28.87000)          LONGITUDE:  82° 43.4' W ( -82.72330)


The bench mark is a disk located on the north shore of the island, 44 m (145 ft)
west of bench mark 7333 D 1978, 15 m (50 ft) north of the south shore of the
island, 6 m (20 ft) from the seaward edge, 3 m (10 ft) north of the mangrove
line, and 1 m (2 ft) north of a witness post.  The bench mark is set 0.37 m (1.2
ft) above ground level, crimped to the top of a copper-clad steel rod driven 6.1
m (20 ft) to refusal, and encased in a PVC pipe and concrete kickblock.

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

                                                                                
Station ID: 8727333                         PUBLICATION DATE:  04/01/2004
Name:       SHARK RIVER, CRYSTAL BAY                          
            FL
NOAA Chart: 11409                           Latitude:   28° 52.2' N (  28.87000)
USGS Quad:  OZELLO                          Longitude:  82° 43.4' W ( -82.72330)


                            T I D A L   D A T U M S 


Tidal datums at SHARK RIVER, CRYSTAL BAY based on:

     LENGTH OF SERIES:      6 MONTHS
     TIME PERIOD:           June 1978 - November 1978
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  8727520 CEDAR KEY, GULF OF MEXICO


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

     MEAN HIGHER HIGH WATER                     MHHW   =  1.112
     MEAN HIGH WATER                            MHW    =  1.005
     MEAN TIDE LEVEL                            MTL    =  0.576
     MEAN SEA LEVEL                             MSL    =  0.570
     MEAN LOW WATER                             MLW    =  0.146
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     7333 A 1978                                 1.038    0.033
     7333 B 1978                                 1.046    0.041
     7333 C 1978                                 1.152    0.147
     7333 D 1978                                 1.155    0.150
     7333 E 1978                                 1.191    0.186


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

                                                                                
Station ID: 8727333                         PUBLICATION DATE:  04/01/2004
Name:       SHARK RIVER, CRYSTAL BAY                          
            FL
NOAA Chart: 11409                           Latitude:   28° 52.2' N (  28.87000)
USGS Quad:  OZELLO                          Longitude:  82° 43.4' W ( -82.72330)


                             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.