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

                                                                                
Station ID: 8728711                         PUBLICATION DATE:  07/14/2003
Name:       APALACHICOLA RIVER                                
            FL
NOAA Chart: 11401                           Latitude:   29° 45.8' N (  29.76330)
USGS Quad:  JACKSON RIVER                   Longitude:  85°  2.0' W ( -85.03330)


To reach the tidal bench marks from U.S. Highway 98 and County Road C-384 (12th
Street) in Apalachicola, proceed 6.6 km (4.1 mi) NW on County Road C-384 to the
Apalachicola Northern Railroad crossing, then continue north along the railroad
to the bridge over the Apalachicola River.  The bench marks are located south of
the railroad bridge along Krista Road on the west side of the tracks.  The tide
gage and staff were located on the south bridge fender on the west west side of
the tracks.


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


                 PRIMARY BENCH MARK STAMPING:  8711 A 1978
                         DESIGNATION:          872 8711 A TIDAL

MONUMENTATION:           Survey disk                           VM#:         9869
AGENCY:                  Florida Department of Natural Resources
                         (FLDNR)                               IDB PID#:  AS0904
SETTING CLASSIFICATION:  Concrete bridge foundation            OPUS PID:        
LATITUDE:   29° 45.9' N (  29.76500)          LONGITUDE:  85°  2.0' W ( -85.03330)


The primary bench mark is a disk set in the SW corner of the concrete foundation
for the west bridge pier at the south end of the Apalachicola Northern Railroad
bridge over the Apalachicola River, 7.99 m (26.2 ft) west of the south end of
the swing span, 2.19 m (7.2 ft) south of the north edge of the foundation, 1.13
m (3.7 ft) NE of the SW corner of the foundation, and 4.51 m (14.8 ft) below the
level of the tracks.

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

                                                                                
Station ID: 8728711                         PUBLICATION DATE:  07/14/2003
Name:       APALACHICOLA RIVER                                
            FL
NOAA Chart: 11401                           Latitude:   29° 45.8' N (  29.76330)
USGS Quad:  JACKSON RIVER                   Longitude:  85°  2.0' W ( -85.03330)


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


                         BENCH MARK STAMPING:  A 296 1967
                         DESIGNATION:          A 296

MONUMENTATION:           Tidal Station disk                    VM#:         9868
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  AS0145
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   29° 45.5' N (  29.75830)          LONGITUDE:  85°  2.0' W ( -85.03330)


The bench mark is a disk located near the County Road C-384 crossing of the
Apalachicola Northern Railroad, 250 m (820 ft) SE of bench mark 8711 D 1978, 43
m (142 ft) NW of the center of the crossing of the highway and the main tracks,
1 m (3 ft) south of utility pole #56X1493R, and 0.15 m (0.5 ft) NW of a witness
post.  The bench mark is set 0.76 m (2.5 ft) below the level of the tracks,
crimped to the top of a copper-clad steel rod driven 20 m (64 ft), and encased
in a 4-inch metal pipe projecting 0.12 m (0.4 ft) above ground.



                         BENCH MARK STAMPING:  8711 B 1978
                         DESIGNATION:          872 8711 B

MONUMENTATION:           Survey disk                           VM#:         9870
AGENCY:                  Florida Department of Natural Resources
                         (FLDNR)                               IDB PID#:  AS0903
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   29° 45.7' N (  29.76170)          LONGITUDE:  85°  2.1' W ( -85.03500)


The bench mark is a disk set in the top of a concrete monument, 0.2 km (0.1 mi)
NE on Krista Road from its intersection with County Road C-384, 30 m (100 ft)
east of the centerline of Krista Road, 21.34 m (70.0 ft) south of the SE corner
of Roland Wilson's house, 14.17 m (46.5 ft) west of the west rail of the
Apalachicola Northern Railroad, 2.59 m (8.5 ft) north of a fence corner of a
yard with a small house and trailer, 0.3 m (1 ft) west of a witness post, and
0.06 m (0.2 ft) below ground level.

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

                                                                                
Station ID: 8728711                         PUBLICATION DATE:  07/14/2003
Name:       APALACHICOLA RIVER                                
            FL
NOAA Chart: 11401                           Latitude:   29° 45.8' N (  29.76330)
USGS Quad:  JACKSON RIVER                   Longitude:  85°  2.0' W ( -85.03330)


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


                         BENCH MARK STAMPING:  8711 C 1978
                         DESIGNATION:          872 8711 C

MONUMENTATION:           Survey disk                           VM#:         9871
AGENCY:                  Florida Department of Natural Resources
                         (FLDNR)                               IDB PID#:  AS0902
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   29° 45.7' N (  29.76170)          LONGITUDE:  85°  2.1' W ( -85.03500)


The bench mark is a disk located 0.1 km (0.05 mi) NE along Krista Road from its
intersection with County Road 384, 30 m (100 ft) west and 84 m (274 ft) south of
bench mark 8711 B 1978, 13 m (43 ft) SSW of a 1 m (2 ft) diameter double-trunk
magnolia tree, 6 m (20 ft) east of the centerline of Krista Road, 2.23 m (7.3
ft) north of a 0.30 m (1.0 ft) diameter water oak tree, and 1.37 m (4.5 ft) west
of a witness post.  The bench mark is set 6 cm (0.2 ft) above ground level,
crimped to the top of a copper-clad steel rod driven 14.6 m (48 ft) to
substantial resistance, and encased in a 4-inch steel pipe and concrete
kickblock.



                         BENCH MARK STAMPING:  8711 D 1978
                         DESIGNATION:          872 8711 D

MONUMENTATION:           Survey disk                           VM#:         9872
AGENCY:                  Florida Department of Natural Resources
                         (FLDNR)                               IDB PID#:  AS0901
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   29° 45.7' N (  29.76170)          LONGITUDE:  85°  2.1' W ( -85.03500)


The bench mark is a disk set in the top of a concrete monument, 99 m (324 ft) SW
of bench mark 8711 C 1978, 12.80 m (42.0 ft) NE of powerline pole #56X-1495R, 11
m (36 ft) NW of the centerline of Krista Road, 6.40 m (21.0 ft) NE of the
centerline of County Road C-384, 2.83 m (9.3 ft) SW of a powerline anchor pole,
1.43 m (4.7 ft) SW of a witness post, and 6 cm (0.2 ft) below ground level.

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

                                                                                
Station ID: 8728711                         PUBLICATION DATE:  07/14/2003
Name:       APALACHICOLA RIVER                                
            FL
NOAA Chart: 11401                           Latitude:   29° 45.8' N (  29.76330)
USGS Quad:  JACKSON RIVER                   Longitude:  85°  2.0' W ( -85.03330)


                            T I D A L   D A T U M S 


Tidal datums at APALACHICOLA RIVER based on:

     LENGTH OF SERIES:      1 YEAR
     TIME PERIOD:           December 1981 - November 1982
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  8728690 APALACHICOLA, APALACHICOLA RIVER


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

     HIGHEST OBSERVED WATER LEVEL (02/03/1978)         =  0.950
     MEAN HIGHER HIGH WATER                     MHHW   =  0.412
     MEAN HIGH WATER                            MHW    =  0.387
     MEAN TIDE LEVEL                            MTL    =  0.241
     MEAN SEA LEVEL                             MSL    =  0.232
     North American Vertical Datum              NAVD88 =  0.127
     MEAN LOW WATER                             MLW    =  0.094
     MEAN LOWER LOW WATER                       MLLW   =  0.000
     LOWEST  OBSERVED WATER LEVEL (12/11/1981)         = -0.470

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     8711 A 1978                                 1.151    0.764
     A 296 1967                                  1.766    1.379
     8711 B 1978                                 1.546    1.159
     8711 C 1978                                 1.969    1.582
     8711 D 1978                                 1.959    1.572


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

                                                                                
Station ID: 8728711                         PUBLICATION DATE:  07/14/2003
Name:       APALACHICOLA RIVER                                
            FL
NOAA Chart: 11401                           Latitude:   29° 45.8' N (  29.76330)
USGS Quad:  JACKSON RIVER                   Longitude:  85°  2.0' W ( -85.03330)


                             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.