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

                                                                                
Station ID: 8721138                         PUBLICATION DATE:  07/02/2003
Name:       HALIFAX RIVER, PONCE INLET                        
            FL
NOAA Chart: 11484                           Latitude:   29°  4.9' N (  29.08170)
USGS Quad:  NEW SMYRNA BEACH                Longitude:  80° 56.2' W ( -80.93670)


To reach the tidal bench marks from Ponce de Leon Inlet, proceed north to Beach
Street, then proceed west on Beach Street to the Down the Hatch Restuarant on
the Halifax River.  The bench marks are along Beach Street, Peninsula Drive and
in the vicinity of the Down the Hatch Restuarant.  The tide gage and staff were
located on the NW end of the pier at the restuarant.


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


                 PRIMARY BENCH MARK STAMPING:  5 1974
                         DESIGNATION:          872 1138 TIDAL 5

MONUMENTATION:           Tidal Station disk                    VM#:         5295
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  AQ1525
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   29°  4.9' N (  29.08170)          LONGITUDE:  80° 56.1' W ( -80.93500)


The primary bench mark is a disk set flush in the top of a 0.24 m (0.8 ft)
square concrete monument at the SW corner of the intersection of Beach Street
and Sailfish Drive, 12.2 m (40 ft) west of the fire hydrant across Sailfish
Drive, 5 m (18 ft) SSE of the centerline of Beach Street, 1 m (4 ft) SE of a
power line pole, and 0.15 m (0.5 ft) below the pavement.

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

                                                                                
Station ID: 8721138                         PUBLICATION DATE:  07/02/2003
Name:       HALIFAX RIVER, PONCE INLET                        
            FL
NOAA Chart: 11484                           Latitude:   29°  4.9' N (  29.08170)
USGS Quad:  NEW SMYRNA BEACH                Longitude:  80° 56.2' W ( -80.93670)


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


                         BENCH MARK STAMPING:  T 318 1970
                         DESIGNATION:          T 318

MONUMENTATION:           Bench Mark disk                       VM#:         5292
AGENCY:                  National Geodetic Survey (NGS)        IDB PID#:  AQ1391
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   29°  5.1' N (  29.08500)          LONGITUDE:  80° 55.6' W ( -80.92670)


The bench mark is a disk set in the top of a concrete monument 86 m (282 ft)
west of the intersection of Beach Street and South Atlantic Avenue, 5 m (16 ft)
south of the approximate centerline of Beach Street, 0.6 m (2 ft) east of the
first power line pole west of the junction, 0.46 m (1.5 ft) west of a metal
witness post, and 0.30 m (1.0 ft) below ground level.

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

                                                                                
Station ID: 8721138                         PUBLICATION DATE:  07/02/2003
Name:       HALIFAX RIVER, PONCE INLET                        
            FL
NOAA Chart: 11484                           Latitude:   29°  4.9' N (  29.08170)
USGS Quad:  NEW SMYRNA BEACH                Longitude:  80° 56.2' W ( -80.93670)


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


                         BENCH MARK STAMPING:  N 320 1970
                         DESIGNATION:          N 320

MONUMENTATION:           Bench Mark disk                       VM#:         5293
AGENCY:                  National Geodetic Survey (NGS)        IDB PID#:  AQ1392
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   29°  5.1' N (  29.08500)          LONGITUDE:  80° 55.9' W ( -80.93170)


The bench mark is a disk set in the top of a concrete monument about 76 m (250
ft) SE of the SE side of Ponce de Leon Inlet Lighthouse, 58 m (191 ft) north of
the centerline of South Peninsula Drive, 0.9 m (3 ft) west of the center of a
steel gate in the fence line, 0.43 m (1.4 ft) east of a metal witness post, 0.30
m (1.0 ft) south of the south side of a hurricane fence line, and 0.06 m (0.2
ft) above ground level.



                         BENCH MARK STAMPING:  1 1974
                         DESIGNATION:          872 1138 TIDAL 1

MONUMENTATION:           Tidal Station disk                    VM#:         5294
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  AQ1528
SETTING CLASSIFICATION:  Concrete sea wall                     OPUS PID:        
LATITUDE:   29°  4.9' N (  29.08170)          LONGITUDE:  80° 56.1' W ( -80.93500)


The bench mark is a disk set flush in the top of a concrete seawall on the SE
corner of the pier at the Down the Hatch Restuarant, 6 m (20 ft) south of the
concrete seawall on the south side of the boat slip, 0.46 m (1.5 ft) south of
the concrete ramp leading to the pier, and at ground level.

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

                                                                                
Station ID: 8721138                         PUBLICATION DATE:  07/02/2003
Name:       HALIFAX RIVER, PONCE INLET                        
            FL
NOAA Chart: 11484                           Latitude:   29°  4.9' N (  29.08170)
USGS Quad:  NEW SMYRNA BEACH                Longitude:  80° 56.2' W ( -80.93670)


                            T I D A L   D A T U M S 


Tidal datums at HALIFAX RIVER, PONCE INLET based on:

     LENGTH OF SERIES:      12 MONTHS
     TIME PERIOD:           February 1974 - January 1975
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  8720030 FERNANDINA BEACH, AMELIA RIVER


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

     HIGHEST OBSERVED WATER LEVEL (10/06/1974)         =  1.584
     MEAN HIGHER HIGH WATER                     MHHW   =  0.965
     MEAN HIGH WATER                            MHW    =  0.883
     North American Vertical Datum              NAVD88 =  0.684
     MEAN TIDE LEVEL                            MTL    =  0.463
     MEAN SEA LEVEL                             MSL    =  0.458
     MEAN LOW WATER                             MLW    =  0.044
     MEAN LOWER LOW WATER                       MLLW   =  0.000
     LOWEST  OBSERVED WATER LEVEL (02/26/1975)         = -0.501

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     5 1974                                      1.779    0.896
     T 318 1970                                  4.352    3.469
     N 320 1970                                  3.774    2.891
     1 1974                                      1.810    0.927


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

                                                                                
Station ID: 8721138                         PUBLICATION DATE:  07/02/2003
Name:       HALIFAX RIVER, PONCE INLET                        
            FL
NOAA Chart: 11484                           Latitude:   29°  4.9' N (  29.08170)
USGS Quad:  NEW SMYRNA BEACH                Longitude:  80° 56.2' W ( -80.93670)


                             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.