U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  6

                                                                                
Station ID: 8722381                         PUBLICATION DATE:  07/06/2009
Name:       GREAT POCKET,ST. LUCIE INLET                      
            FL
NOAA Chart: 11474                           Latitude:   27°  9.3' N (  27.15500)
USGS Quad:  ST. LUCIE INLET                 Longitude:  80° 10.3' W ( -80.17170)


To reach the tidal bench marks from the post office in Port Salerno, proceed
0.72 km (0.45 mi) SE on State Road A1A to Anchor Avenue, then 0.3 km (0.2 mi) NW
on Anchor Avenue to Horseshoe Point Road, then 2.49 km (1.55 mi) ENE on
Horseshoe Point Road to its end.  The bench marks are located at Horseshoe
Point.  The tide gage and staff were located on a finger pier on the south side
of Horseshoe Point.


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


                 PRIMARY BENCH MARK STAMPING:  NO 1 1972
                         DESIGNATION:          872 2381 TIDAL 1

MONUMENTATION:           Tidal Station disk                    VM#:         5454
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  AF6966
SETTING CLASSIFICATION:  Concrete sea wall                     OPUS PID:        
LATITUDE:   27°  9.2' N (  27.15333)          LONGITUDE:  80° 10.3' W ( -80.17170)


The primary bench mark is a disk set flush in the Horseshoe Point concrete sea
wall, 50.29 m (165.0 ft) east of the SW end of the sea wall, and 10.06 m (33.0
ft) east of the easternmost of four finger piers.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  6

                                                                                
Station ID: 8722381                         PUBLICATION DATE:  07/06/2009
Name:       GREAT POCKET,ST. LUCIE INLET                      
            FL
NOAA Chart: 11474                           Latitude:   27°  9.3' N (  27.15500)
USGS Quad:  ST. LUCIE INLET                 Longitude:  80° 10.3' W ( -80.17170)


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


                         BENCH MARK STAMPING:  NO 3 1972
                         DESIGNATION:          872 2381 NO 3 1972

MONUMENTATION:           Tidal Station disk                    VM#:         5456
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  AF6963
SETTING CLASSIFICATION:  Concrete sea wall                     OPUS PID:        
LATITUDE:   27°  9.2' N (  27.15333)          LONGITUDE:  80° 10.3' W ( -80.17170)


The bench mark is a disk set flush in the Horseshoe Point concrete sea wall,
17.37 m (57.0 ft) WNW of bench mark NO 2 1972, 7.32 m (24.0 ft) north of the SW
corner of the sea wall, and 0.52 m (1.7 ft) south of the NW corner of the sea
wall.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  6

                                                                                
Station ID: 8722381                         PUBLICATION DATE:  07/06/2009
Name:       GREAT POCKET,ST. LUCIE INLET                      
            FL
NOAA Chart: 11474                           Latitude:   27°  9.3' N (  27.15500)
USGS Quad:  ST. LUCIE INLET                 Longitude:  80° 10.3' W ( -80.17170)


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


                         BENCH MARK STAMPING:  SNAKE 1930 1979
                         DESIGNATION:          Snake Reset

MONUMENTATION:           Bench Mark disk                       VM#:         5458
AGENCY:                  National Geodetic Survey (NGS)        IDB PID#:  AF6967
SETTING CLASSIFICATION:  Concrete post                         OPUS PID#: AF6967
LATITUDE:   27°  9.2' N (  27.15333)          LONGITUDE:  80° 10.3' W ( -80.17170)


The bench mark is a disk set in the top of a concrete post projecting 12-inches,
0.21 m (0.7 ft) west of a witness post 4.15 m (13.6 ft) north of Horseshoe Point
Road centerline, 4.57 m (15.0 ft) SW of a seagrape tree, and about 71.93 m
(236.0 ft) west of the east end of Horseshoe Point sea wall.    

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  6

                                                                                
Station ID: 8722381                         PUBLICATION DATE:  07/06/2009
Name:       GREAT POCKET,ST. LUCIE INLET                      
            FL
NOAA Chart: 11474                           Latitude:   27°  9.3' N (  27.15500)
USGS Quad:  ST. LUCIE INLET                 Longitude:  80° 10.3' W ( -80.17170)


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


                         BENCH MARK STAMPING:  Mar 8 1980
                         DESIGNATION:          Mar 8 FLDT

MONUMENTATION:           Bench Mark disk                       VM#:        18911
AGENCY:                  Florida Department of Transportation
                         (FLDT)                                IDB PID#:  AF6961
SETTING CLASSIFICATION:  Concrete Bridge Rail                  OPUS PID:        
LATITUDE:   27°  8.8' N (  27.14667)          LONGITUDE:  80° 11.5' W ( -80.19167)


The bench mark is a disk located is 5.55 m (18.2 ft) NNW of Horseshoe Point Road
centerline, 0.64 m (2.1 ft) WSW of the east end of the concrete rail, 16.31 m
(53.5 ft) WSW of the east end of a metal guardrail, and 0.91 m (3.0 ft) above
the road.  



                         BENCH MARK STAMPING:  2381 A 2005
                         DESIGNATION:          872 2381 A TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:        18912
AGENCY:                  Florida Department of Environmental
                         Protection                            IDB PID#:        
SETTING CLASSIFICATION:  Concrete Monument                     OPUS PID#: DM3745
LATITUDE:   27°  9.2' N (  27.15333)          LONGITUDE:  80° 10.3' W ( -80.17167)


The bench mark is a disk set flush in the top of a concrete monument on the
North edge of pavement and level with Horseshoe Point Road 8.11 m (26.6 ft) east
of the mark designated Snake Reset, 6.10 m (20.0 ft) south of the waters edge of
Great Pocket, 3.35 m (11.0 ft) north of the approximate centerline of Horseshoe
Point Road, 2.99 m (9.8 ft) south of a cinderblock sea wall, and 2.80 m (9.2 ft)
south of a carsonite witness post.  

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  5 of  6

                                                                                
Station ID: 8722381                         PUBLICATION DATE:  07/06/2009
Name:       GREAT POCKET,ST. LUCIE INLET                      
            FL
NOAA Chart: 11474                           Latitude:   27°  9.3' N (  27.15500)
USGS Quad:  ST. LUCIE INLET                 Longitude:  80° 10.3' W ( -80.17170)


                            T I D A L   D A T U M S 


Tidal datums at GREAT POCKET,ST. LUCIE INLET based on:

     LENGTH OF SERIES:      5 MONTHS
     TIME PERIOD:           August 1972 - December 1972
     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:

     North American Vertical Datum              NAVD88 =  0.477
     MEAN HIGHER HIGH WATER                     MHHW   =  0.395
     MEAN HIGH WATER                            MHW    =  0.363
     MEAN TIDE LEVEL                            MTL    =  0.202
     MEAN SEA LEVEL                             MSL    =  0.201
     MEAN LOW WATER                             MLW    =  0.040
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     NO 1 1972                                   1.304    0.941
     NO 3 1972                                   1.168    0.805
     SNAKE 1930 1979                             1.493    1.130
     Mar 8 1980                                  3.664    3.301
     2381 A 2005                                 1.597    1.234


Foot Notes:

Bench marks Mar 8 1980 and 2381 A 2005 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  6 of  6

                                                                                
Station ID: 8722381                         PUBLICATION DATE:  07/06/2009
Name:       GREAT POCKET,ST. LUCIE INLET                      
            FL
NOAA Chart: 11474                           Latitude:   27°  9.3' N (  27.15500)
USGS Quad:  ST. LUCIE INLET                 Longitude:  80° 10.3' W ( -80.17170)


                             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.