Superseded Bench Mark Sheet for 8728786, ELEVEN MILE, ST. VINCENT SOUND

Present Epoch

Printable version

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

                                                   PUBLICATION DATE:  02/14/1985
Station ID: 8728786                                SUPERCEDED DATE:   04/21/2003
Name:       ELEVEN MILE, ST. VINCENT SOUND                    
            FLORIDA
NOAA Chart: 11401                                  Latitude:         29° 42.4' N
USGS Quad:  INDIAN PASS                            Longitude:        85°  9.2' W


To reach the tidal bench marks proceed west along U.S. Highway 98 from
Appalachicola, 8.0 miles (12.9 km) to the intersection of U.S. Highway 98 and S
30, continue left along S 30 for for 2.8 miles (4.5 km) to a dirt and oyster
shell road at Eleven Mile, then 0.2 mile (0.3 km) to the end of the road and to
Eleven Mile Oyster Farm and Store. The bench mark are along S 30 and the road to
the boat house, and the tide gage and staff were located on the Eleven Mile
Oyster Farm.


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


                 PRIMARY BENCH MARK STAMPING:  8786 A 1977

MONUMENTATION:           Survey Disk                               VM#:     9884
AGENCY:                                                            PID#:  AS0872
SETTING CLASSIFICATION:  Copper-clad Steel Rod


The bench mark is 58.0 feet (17.7 m) SE of the NE corner of the easterly dock,
18.0 feet (5.5 m) ENE of the centerline the dirt road, 6.5 feet (2.0 m) SE of
utility pole No. 56X 2661R, and 2 feet (0.6 m) west of a witness post.  The
bench mark is at ground level, crimped to a copper-clad steel rod driven 48 feet
(15 m), and encased in a PVC protector pipe and concrete kickblock.



                         BENCH MARK STAMPING:  8786 B 1977

MONUMENTATION:           Survey Disk                               VM#:     9885
AGENCY:                                                            PID#:  AS0871
SETTING CLASSIFICATION:  Concrete Monument


The bench mark is 337 feet (103 m) NW along the dirt road from Bench Mark 8786 A
1977, 77.5 feet (23.6 m) NNW of utility pole No. 6 X 860R with transformer, 45.0
feet (13.7 m) WSW of a 5 feet (2 m) diameter oak, 15.0 feet (4.6 m) west of the
centerline of the dirt road, 1.7 feet (0.5 m) SE of a witness post, at ground
level, level with the centerline of the road, and set in a concrete monument.

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

                                                   PUBLICATION DATE:  02/14/1985
Station ID: 8728786                                SUPERCEDED DATE:   04/21/2003
Name:       ELEVEN MILE, ST. VINCENT SOUND                    
            FLORIDA
NOAA Chart: 11401                                  Latitude:         29° 42.4' N
USGS Quad:  INDIAN PASS                            Longitude:        85°  9.2' W


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


                         BENCH MARK STAMPING:  8786 C 1977

MONUMENTATION:           Survey Disk                               VM#:     9886
AGENCY:                                                            PID#:  AS0870
SETTING CLASSIFICATION:  Concrete Monument


The bench mark is 296 feet (90 m) north of Bench Mark 8786 B 1977, 42.0 feet
(12.8 m) SE of utility pole No. 56X 1859R, 34.0 feet (10.4 m) NW of a 1.5 foot
(0.5 m) diameter palm tree, 26.0 feet (7.9 m) ENE of the centerline of the dirt
road, 4 feet (1.2 m) WNW of a witness post, at ground level and set in a
concrete monument.



                         BENCH MARK STAMPING:  8786 D 1977

MONUMENTATION:           Survey Disk                               VM#:     9887
AGENCY:                                                            PID#:  AS0869
SETTING CLASSIFICATION:  Copper-clad Steel Rod


The bench mark is 268 feet (82 m) north of Bench Mark 8766 C 1977, 86.0 feet
(26.2 m) SSE of the centerline of Highway S 30, 24.0 feet (7.3 m) ENE of the
centerline of the road to Eleven Mile Oyster farm and store, 10.3 feet (3.1 m)
WSW of SW corner of abandoned white building, 11.0 feet (3.4 m) NNW of utility
pole No. 56X 1790R, and 1.8 feet (0.5 m) WSW of a witness post.  The bench mark
is at ground level, crimped to a copper-clad steel rod driven 15.5 feet (4.7 m),
and encased in a PVC protector pipe and concrete kickblock.

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

                                                   PUBLICATION DATE:  02/14/1985
Station ID: 8728786                                SUPERCEDED DATE:   04/21/2003
Name:       ELEVEN MILE, ST. VINCENT SOUND                    
            FLORIDA
NOAA Chart: 11401                                  Latitude:         29° 42.4' N
USGS Quad:  INDIAN PASS                            Longitude:        85°  9.2' W


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


                         BENCH MARK STAMPING:  8786 E 1977

MONUMENTATION:           Survey Disk                               VM#:     9888
AGENCY:                                                            PID#:  AS0520
SETTING CLASSIFICATION:  Concrete Monument


The bench mark is NE of Bench Mark 8786 D 1977, 193.0 feet (58.8 m) east of
Eleven Mile Farm dirt road, 38.6 feet (11.8 m) NNW of the centerline of Highway
S 30, 22.0 feet (6.7 m) SE of a witness post, at ground level, 1 foot (0.3 m)
below the centerline of the highway and set in a concrete monument.

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

                                                   PUBLICATION DATE:  02/14/1985
Station ID: 8728786                                SUPERCEDED DATE:   04/21/2003
Name:       ELEVEN MILE, ST. VINCENT SOUND                    
            FLORIDA
NOAA Chart: 11401                                  Latitude:         29° 42.4' N
USGS Quad:  INDIAN PASS                            Longitude:        85°  9.2' W


                            T I D A L   D A T U M S 


Tidal datums at ELEVEN MILE, ST. VINCENT SOUND based on:

     LENGTH OF SERIES:      6 MONTHS
     TIME PERIOD:           DECEMBER 1977 - MAY 1978
     TIDAL EPOCH:           1960-1978
     CONTROL TIDE STATION:  8729840 PENSACOLA


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

     HIGHEST OBSERVED WATER LEVEL (05/04/1978)         =   2.91
     MEAN HIGHER HIGH WATER                     MHHW   =   1.69
     MEAN HIGH WATER                            MHW    =   1.55
     MEAN TIDE LEVEL                            MTL    =   0.99
     MEAN LOW WATER                             MLW    =   0.43
     MEAN LOWER LOW WATER                       MLLW   =   0.00
     LOWEST  OBSERVED WATER LEVEL (02/22/1985)         =  -1.71

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In FEET above:

     Stamping or Designation                    MLLW        MHW

     8786 A 1977                                 3.43      1.88
     8786 B 1977                                 6.65      5.10
     8786 C 1977                                 5.78      4.23
     8786 D 1977                                 7.90      6.35
     8786 E 1977                                10.23      8.68


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

                                                   PUBLICATION DATE:  02/14/1985
Station ID: 8728786                                SUPERCEDED DATE:   04/21/2003
Name:       ELEVEN MILE, ST. VINCENT SOUND                    
            FLORIDA
NOAA Chart: 11401                                  Latitude:         29° 42.4' N
USGS Quad:  INDIAN PASS                            Longitude:        85°  9.2' W


                             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 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.

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