U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  8

                                                                                
Station ID: 8720001                         PUBLICATION DATE:  03/25/2010
Name:       ST. MARYS RIVER HEADWATERS                        
            FL
NOAA Chart: 11502                           Latitude:   30° 47.2' N (  30.78670)
USGS Quad:  KINGS FERRY                     Longitude:  81° 50.4' W ( -81.84000)


To reach the tidal bench marks from the intersection of U.S. Highway 17 and
State Road A1A (State Road 200) in Yulee, go north on U.S. 17 for 7.2 km (4.5
mi) to County Road 108, turn left on County Road 108 and go 15.4 km (9.6 mi) to
County 121A, turn right on County Road 121A and go north for 10.6 km (6.6 mi) to
Kings Ferry and the junction of a connector road to County Road 115A and Bailey
Haddock Lane.  The bench marks are located in the vicinity of Bailey Haddock
Lane, the connector road and County Road 115A.  The tide gauge and staff were
located on the NW corner of a dock on the St. Marys River behind the 2-story
brick residence located east of the end of Bailey Haddock Lane.  


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


                 PRIMARY BENCH MARK STAMPING:  0001 B 1977
                         DESIGNATION:          872 0001 B TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         4961
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  BC2413
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   30° 47.1' N (  30.78500)          LONGITUDE:  81° 50.4' W ( -81.84000)


The primary bench mark is a disk located 33.8 m (111.0 ft) SW of the center of a
driveway entrance to Kings Plantation, 32.6 m (107.0 ft) SW of the centerline of
Bailey Haddack Lane, 17.2 m (56.3 ft) SE of a 4.4 m (14.5 ft) diameter oak tree
in the middle of the guardrail structure, 9.6 m (31.6 ft) east of the NE end of
the guardrail in the middle of the highway, 4.5 m (14.8 ft) south of the
centerline of Middle Road and 0.3 m (1.0 ft) North of a metal witness post.  The
bench mark is set 0.06 m (0.2 ft) below ground level, attached to a the top of a
copper-clad rod, driven in the ground and encased in a 4-inch PVC pipe flush
with the ground and about level with Lake Hampton Road.  The disk is recessed
0.2 m (0.5 ft) below the level of the PVC pipe.    NOTE:  A magnet is buried at
the south side of the monument.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  8

                                                                                
Station ID: 8720001                         PUBLICATION DATE:  03/25/2010
Name:       ST. MARYS RIVER HEADWATERS                        
            FL
NOAA Chart: 11502                           Latitude:   30° 47.2' N (  30.78670)
USGS Quad:  KINGS FERRY                     Longitude:  81° 50.4' W ( -81.84000)


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


                         BENCH MARK STAMPING:  105 CMP 1970
                         DESIGNATION:          105 CMP

MONUMENTATION:           Tidal Station disk                    VM#:         4958
AGENCY:                  U.S. Department of Interior           IDB PID#:  BC2410
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   30° 45.9' N (  30.76500)          LONGITUDE:  81° 50.9' W ( -81.84833)


The bench mark is a disk set flush in the top of a concrete monument flush with
the ground 1.0 km (0.6 mi) NE of the Y-fork of County Road 115A.  Go 10.6 km
(6.6 mi) northeasterly on County Road 115A.  The bench mark is 19.02 m (62.4 ft)
ESE of the centerline of County Road 115A, 4.15 m (13.6 ft) SSW of a dirt drive
leading east, and 0.3 m (1 ft) west of a wood corner fence post and 0.3 m (1 ft)
above the highway.     NOTE  A magnet is buried at the south side of the mark.



                         BENCH MARK STAMPING:  106 CMP 1970
                         DESIGNATION:          106 CMP

MONUMENTATION:           Tidal Station disk                    VM#:         4959
AGENCY:                  U.S. Department of Interior           IDB PID#:  BC2411
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   30° 46.7' N (  30.77830)          LONGITUDE:  81° 50.7' W ( -81.84500)


The bench mark is a disk set flush in a concrete monument that is flush with the
ground, 12.1 km (7.5 mi) NE on Road S 115A, 1.0 km (0.6 mi) NE on County Road C
108 to the y-fork of Road S 115A from the intersection of U.S. Highway 1/301 and
County Road C 108.  The mark bears 19.2 m (56.4 feet) NW of the centerline of
Road S 115A, 5.5 m (18 feet) SW of a drainage slough.  The bench mark is 0.5 m
(1.5 feet) NW of a witness post.    NOTE:  A magnet is buried at the south side
of the mark.  

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  8

                                                                                
Station ID: 8720001                         PUBLICATION DATE:  03/25/2010
Name:       ST. MARYS RIVER HEADWATERS                        
            FL
NOAA Chart: 11502                           Latitude:   30° 47.2' N (  30.78670)
USGS Quad:  KINGS FERRY                     Longitude:  81° 50.4' W ( -81.84000)


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


                         BENCH MARK STAMPING:  0001 D 2004
                         DESIGNATION:          0001 D TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:        19162
AGENCY:                  Florida Dept. of Environmental
                         Protection (FLDEP)                    IDB PID#:        
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   30° 47.2' N (  30.78667)          LONGITUDE:  81° 50.4' W ( -81.84000)


The bench mark is a stainless steel rod located 0.8 km (0.05 mi) from the
junction of Kolars Ferry Road and Bill Johnson Road on the left, turn left on
Bill Johnson Road and go NNW for 0.16 km (0.1 mi) to a county boat ramp at the
St. Marys River and the mark on the left near the NE corner of the property at
49124 Bill Johnson Road, approximately 30.4 m (100.0 ft) south of the St. Marys
River, 5.2 m (16.5 ft) east of a round concrete electric transmission line pole,
4.14 m (13.6 ft) west of the west edge of a 3.96 m (13.0 ft) wide concrete drive
to the boat ramp, 0.91 m (3.0 ft) SE of the NE corner post for a 1.21 m (4.0 ft)
high chain link fence and 0.76 m (2.5 ft) east of the chain link fence and a
carsonite witness post.  The bench mark is a stainless steel rod driven to
refusal at a depth of 4.0 m (13.2 ft) with an NGS logo cap, flush with the
ground, about 0.3 m (1.0 ft) above the level of the concrete boat ramp drive. 
The datum point is recessed 0.15 m (0.5 ft) below the level of the NGS logo cap
being of a stainless steel rod.  Access to the datum point is had through the
5-inch NGS logo cap.    NOTE  A magnet is buried at the south side of the mark. 
       

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  8

                                                                                
Station ID: 8720001                         PUBLICATION DATE:  03/25/2010
Name:       ST. MARYS RIVER HEADWATERS                        
            FL
NOAA Chart: 11502                           Latitude:   30° 47.2' N (  30.78670)
USGS Quad:  KINGS FERRY                     Longitude:  81° 50.4' W ( -81.84000)


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


                         BENCH MARK STAMPING:  0001 E 2004
                         DESIGNATION:          0001 E TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:        19163
AGENCY:                  Florida Dept. of Environmental
                         Protection (FLDEP)                    IDB PID#:        
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   30° 47.0' N (  30.78333)          LONGITUDE:  81° 50.5' W ( -81.84170)


The bench mark is a disk set flush in the top of a round concrete monument
located about 113.7 m (373.0 ft) south of the approximate centerline of Kolars
Ferry Road, 10.61 m (34.8 ft) ESE of the approximate centerline of County Road
115A, 8.28 m (27.5 ft) WSW of the corner fence post of the NW corner of a NE-SW
power line easement, 6.24 m (20.5 ft) SSW of the innermost of 2 wire power pole
anchors, 1.829 m (6.0 ft) NNE of a wooden power pole and 0.15 m (0.5 ft) west of
a carsonite witness post.  The bench mark is recessed 0.06 (0.2 ft) below the
level of the ground and about 0.3 m (1.0 ft) below the level of County Road
115A.     NOTE  A magnet is buried at the south side of the mark.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  5 of  8

                                                                                
Station ID: 8720001                         PUBLICATION DATE:  03/25/2010
Name:       ST. MARYS RIVER HEADWATERS                        
            FL
NOAA Chart: 11502                           Latitude:   30° 47.2' N (  30.78670)
USGS Quad:  KINGS FERRY                     Longitude:  81° 50.4' W ( -81.84000)


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


                         BENCH MARK STAMPING:  0001 F 2004
                         DESIGNATION:          0001 F TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:        19164
AGENCY:                  Florida Dept. of Environmental
                         protection                            IDB PID#:        
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   30° 46.9' N (  30.78167)          LONGITUDE:  81° 50.6' W ( -81.84333)


The bench mark is a disk set in the top of a round concrete monument located
about 52.12 m (171.0 ft) north of Triangle Drive, 25.36 m (83.2 ft) WNW and
across County Road 115A from a wooden power pole number F292040, 13.11 m (43.0
ft) WNW of the approximate centerline of County Road 115A, 2.26 m (7.4 ft) east
of a 1.219 m (4.0 ft) high hogwire fence, 1.67 m (5.5 ft) NE of a wooden
powerline anchor pole and 0.15m (0.5 ft) east of a carsonite witness post.  The
bench mark is recessed 0.09 (0.3 ft) below the level of the ground and about
level with County Road 115A.    NOTE  A magnet is buried at the south side of
the mark.    

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  6 of  8

                                                                                
Station ID: 8720001                         PUBLICATION DATE:  03/25/2010
Name:       ST. MARYS RIVER HEADWATERS                        
            FL
NOAA Chart: 11502                           Latitude:   30° 47.2' N (  30.78670)
USGS Quad:  KINGS FERRY                     Longitude:  81° 50.4' W ( -81.84000)


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


                         BENCH MARK STAMPING:  NASSAU 38 2002
                         DESIGNATION:          NASSAU 38 2002

MONUMENTATION:           Horizontal Station disk               VM#:        19165
AGENCY:                  Nassau County                         IDB PID#:  DE5923
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID#: DE5923
LATITUDE:   30° 47.0' N (  30.78333)          LONGITUDE:  81° 50.5' W ( -81.84170)


The bench mark is a brass Nassau County geodetic control disk set flush in the
top of a 12-inch diameter concrete monument located (94.0 ft) (0.017 Mi) south
of the centerline of Lake Hampton road, (90.0 ft) (0.017 Mi) NE of a 6-inch
square concrete right of way marker projecting (18 in) above ground, (21.9 ft)
(0.004 Mi) NW of the centerline of County Road 115A and (21.8 ft) (0.004 Mi) SE
of a witness post.  The bench mark is recessed (0.5 ft) below the ground.   
NOTE:  A magnet is buried at the south side of the mark.    NOTE:  Lake Hampton
Road is now Kolars Ferry Road.  

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  7 of  8

                                                                                
Station ID: 8720001                         PUBLICATION DATE:  03/25/2010
Name:       ST. MARYS RIVER HEADWATERS                        
            FL
NOAA Chart: 11502                           Latitude:   30° 47.2' N (  30.78670)
USGS Quad:  KINGS FERRY                     Longitude:  81° 50.4' W ( -81.84000)


                            T I D A L   D A T U M S 


Tidal datums at ST. MARYS RIVER HEADWATERS based on:

     LENGTH OF SERIES:      5 MONTHS
     TIME PERIOD:           December 1977 - April 1978
     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:

     MEAN HIGHER HIGH WATER                     MHHW   =  0.973
     MEAN HIGH WATER                            MHW    =  0.927
     MEAN SEA LEVEL                             MSL    =  0.589
     MEAN TIDE LEVEL                            MTL    =  0.497
     North American Vertical Datum              NAVD88 =  0.322
     MEAN LOW WATER                             MLW    =  0.066
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     0001 B 1977                                 5.778    4.851
     105 CMP 1970                                6.120    5.193
     106 CMP 1970                                4.185    3.258
     0001 D 2004                                 2.453    1.526
     0001 E 2004                                 5.079    4.152
     0001 F 2004                                 6.190    5.263
     NASSAU 38 2002                              5.089    4.162


Foot Notes:

Geodetic heights of the bench marks meet all NOAA/NOS/NGS quality control
standards for Second Order, Class 1 leveling.  It is advised that a confirmation
set of levels be established for bench marks 0001 D 2004, 0001 E 2004, 0001 F
2004, and NASSAU 38 2002 to verify height differences before using tidal bench
mark elevation information.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  8 of  8

                                                                                
Station ID: 8720001                         PUBLICATION DATE:  03/25/2010
Name:       ST. MARYS RIVER HEADWATERS                        
            FL
NOAA Chart: 11502                           Latitude:   30° 47.2' N (  30.78670)
USGS Quad:  KINGS FERRY                     Longitude:  81° 50.4' W ( -81.84000)


                             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.