U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  7

                                                                                
Station ID: 8728412                         PUBLICATION DATE:  04/04/2009
Name:       LANARK, ST. GEORGES SOUND                         
            FL
NOAA Chart: 11405                           Latitude:   29° 52.7' N (  29.87830)
USGS Quad:  MCINTYRE                        Longitude:  84° 35.7' W ( -84.59500)


To reach the tidal bench marks from the junction of Parker Street and U.S.
Highway 98 in Lanark, proceed SW along U.S. Highway 98 for 0.32 km (0.2 mi) to
the Lanark Boat Club Marina on the south side of the highway.  The bench marks
are located along U.S. Highway 98.  The tide gage and staff were located on the
club marina dock.


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


                 PRIMARY BENCH MARK STAMPING:  8412 A 1976
                         DESIGNATION:          872 8412 A TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         9823
AGENCY:                  Florida Department of Natural Resources
                         (FLDNR)                               IDB PID#:  AS0923
SETTING CLASSIFICATION:  Concrete culvert head wall            OPUS PID:        
LATITUDE:   29° 52.9' N (  29.88170)          LONGITUDE:  84° 35.7' W ( -84.59500)


The primary bench mark is a disk set in top of the east end of a concrete
culvert head wall on the south side of U.S. Highway 98, 52.73 m (173 ft) SW of
the centerline of the entrance drive to the Lanark Village Boat Club House, 9.20
m (30.2 ft) SE of the centerline of the highway, 7.77 m (25.5 ft) NW of the
corner of the juncture of a run-off channel and the boat marina.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  7

                                                                                
Station ID: 8728412                         PUBLICATION DATE:  04/04/2009
Name:       LANARK, ST. GEORGES SOUND                         
            FL
NOAA Chart: 11405                           Latitude:   29° 52.7' N (  29.87830)
USGS Quad:  MCINTYRE                        Longitude:  84° 35.7' W ( -84.59500)


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


                         BENCH MARK STAMPING:  8412 B 1976
                         DESIGNATION:          872 8412 B TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         9824
AGENCY:                  Florida Department of Natural Resources
                         (FLDNR)                               IDB PID#:  AS0922
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   29° 52.9' N (  29.88170)          LONGITUDE:  84° 35.7' W ( -84.59500)


The bench mark is a disk set along U.S. Highway 98, 13.53 m (44.4 ft) NW of the
centerline of the highway, 11.52 m (37.8 ft) east of a 0.52 m (1.7 ft) diameter
pine tree, 3.20 m (10.5 ft) NE of powerline pole # 5-3124, and 0.3 m (1 ft) SE
of a witness post.  The bench mark is crimped to the top of a copper-clad steel
rod driven 7.3 m (24 ft) to refusal, and encased in a PVC pipe and concrete
kick-block.



                         BENCH MARK STAMPING:  8412 C 1976
                         DESIGNATION:          872 8412 C TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         9825
AGENCY:                  Florida Department of Natural Resources
                         (FLDNR)                               IDB PID#:  AS0921
SETTING CLASSIFICATION:  Concrete culvert head wall            OPUS PID:        
LATITUDE:   29° 52.9' N (  29.88167)          LONGITUDE:  84° 35.6' W ( -84.59330)


The bench mark is a disk set in the center of a concrete culvert head wall,
24.38 m (80.0 ft) east of the center of the junction of Parker Avenue and the
highway, 22.07 m (72.4 ft) NE of the centerline of a dirt road leading to a
roadside park, and 7.71 m (25.3 ft) SE of the centerline of the highway.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  7

                                                                                
Station ID: 8728412                         PUBLICATION DATE:  04/04/2009
Name:       LANARK, ST. GEORGES SOUND                         
            FL
NOAA Chart: 11405                           Latitude:   29° 52.7' N (  29.87830)
USGS Quad:  MCINTYRE                        Longitude:  84° 35.7' W ( -84.59500)


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


                         BENCH MARK STAMPING:  8412 D 1976
                         DESIGNATION:          872 8412 D TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         9826
AGENCY:                  Florida Department of Natural Resources
                         (FLDNR)                               IDB PID#:  AS0920
SETTING CLASSIFICATION:  Concrete culvert head wall            OPUS PID:        
LATITUDE:   29° 53.0' N (  29.88330)          LONGITUDE:  84° 35.5' W ( -84.59170)


The bench mark is a disk set in the center of a concrete culvert head wall,
52.85 m (173.4 ft) east of the centerline of Caldwell Avenue, and 6.92 m (22.7
ft) NW of the centerline of the highway.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  7

                                                                                
Station ID: 8728412                         PUBLICATION DATE:  04/04/2009
Name:       LANARK, ST. GEORGES SOUND                         
            FL
NOAA Chart: 11405                           Latitude:   29° 52.7' N (  29.87830)
USGS Quad:  MCINTYRE                        Longitude:  84° 35.7' W ( -84.59500)


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


                         BENCH MARK STAMPING:  A 298 1967
                         DESIGNATION:          A 298

MONUMENTATION:           Bench Mark disk                       VM#:         9827
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  AS0169
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   29° 52.9' N (  29.88170)          LONGITUDE:  84° 35.6' W ( -84.59330)


The bench mark is a disk located 42.98 m (141.0 ft) west of the center of the
junction of Parker Avenue and U.S. Highway 98, 21.34 m (70.0 ft) NE of the
centerline of Azalea Court, 15.24 m (50.0 ft) NW of the centerline of the
highway, 6.71 m (22.0 ft) NE of a powerline pole, 0.40 m (1.3 ft) east of a
concrete right-of-way marker, and 0.18 m (0.6 ft) west of a metal witness post. 
The bench mark is set 0.30 m (1.0 ft) above the level of the highway, crimped to
the top of a copper-clad steel rod driven 9.60 m (32 ft) to refusal, and encased
in a steel pipe and concrete kickblock.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  5 of  7

                                                                                
Station ID: 8728412                         PUBLICATION DATE:  04/04/2009
Name:       LANARK, ST. GEORGES SOUND                         
            FL
NOAA Chart: 11405                           Latitude:   29° 52.7' N (  29.87830)
USGS Quad:  MCINTYRE                        Longitude:  84° 35.7' W ( -84.59500)


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


                         BENCH MARK STAMPING:  L 293 1967
                         DESIGNATION:          L 293

MONUMENTATION:           Bench Mark disk                       VM#:        19004
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  AS0168
SETTING CLASSIFICATION:  Concrete Monument                     OPUS PID:        
LATITUDE:   29° 52.4' N (  29.87333)          LONGITUDE:  84° 36.5' W ( -84.60833)


The bench mark is a disk located 30.33 m (99.5 ft) west of the center of the
junction of Arizona Street and US Hwy 98, 26.82 m (88.0 ft) SW of the center
line of the road, 14.02 m (46.0 ft) NW of the center line of the highway, 0.91 m
(3.0 ft) NE of power line pole #5841824-R, in line with a row of poles 0.49 m
(1.6 ft) SW of a metal witness post, about level with the highway and set in the
top of a concrete post projecting 0.15 m (0.5 ft) above the level of the ground.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  6 of  7

                                                                                
Station ID: 8728412                         PUBLICATION DATE:  04/04/2009
Name:       LANARK, ST. GEORGES SOUND                         
            FL
NOAA Chart: 11405                           Latitude:   29° 52.7' N (  29.87830)
USGS Quad:  MCINTYRE                        Longitude:  84° 35.7' W ( -84.59500)


                            T I D A L   D A T U M S 


Tidal datums at LANARK, ST. GEORGES SOUND based on:

     LENGTH OF SERIES:      3 MONTHS
     TIME PERIOD:           February 1977 - April 1977
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  8728360 TURKEY POINT


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

     MEAN HIGHER HIGH WATER                     MHHW   =  0.797
     MEAN HIGH WATER                            MHW    =  0.737
     North American Vertical Datum              NAVD88 =  0.500
     MEAN TIDE LEVEL                            MTL    =  0.461
     MEAN SEA LEVEL                             MSL    =  0.452
     MEAN LOW WATER                             MLW    =  0.185
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     8412 A 1976                                 1.916    1.179
     8412 B 1976                                 3.276    2.539
     8412 C 1976                                 3.196    2.459
     8412 D 1976                                 3.414    2.677
     A 298 1967                                  3.801    3.064
     L 293 1967                                  3.250    2.513


Foot Notes:

Bench marks L 293 1967 are based on one differentialleveling 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  7 of  7

                                                                                
Station ID: 8728412                         PUBLICATION DATE:  04/04/2009
Name:       LANARK, ST. GEORGES SOUND                         
            FL
NOAA Chart: 11405                           Latitude:   29° 52.7' N (  29.87830)
USGS Quad:  MCINTYRE                        Longitude:  84° 35.7' W ( -84.59500)


                             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.