Superseded Bench Mark Sheet for 8725782, SHELL CREEK, SEABOARD RR FL

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:  10/04/1984
Station ID: 8725782                                SUPERCEDED DATE:   04/21/2003
Name:       SEABOARD COASTLINE RAILROAD, SHELL CREEK          
            FLORIDA
NOAA Chart: 11426                                  Latitude:         26° 58.7' N
USGS Quad:  CLEVELAND                              Longitude:        81° 58.5' W


To reach the tidal bench marks from the East Charlotte Volunteer Fire Department
building, proceed 2.15 miles (3.46 km) north along U.S. Highway 17 to Tarpon
Drive in San Souci, then 0.6 mile (1.0 km) in a westerly direction along Tarpon
Drive to a dirt trail leading to the Seaboard Coastline Railroad, then SW 0.5
mile (0.80 km) along the dirt trail to the railroad trestle over Shell Creek. 
The bench marks are in the area of the trestle and the tide gage and staff were
lcoated at the NE end of the trestle.


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


                 PRIMARY BENCH MARK STAMPING:  5782 A 1978

MONUMENTATION:           Survey Disk                               VM#:     6067
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Galvanized Steel Rod


The bench mark is at the railroad trestle bridge over Shell Creek, 28.1 feet
(8.6 m) WNW of the west rail of the track, 20.4 feet (6.2 m) NNE of the
shoreline, 19.6 feet (6.0 m) NNW of the NE end of the trestle, and 5.8 feet (1.8
m) SE of a witness post.  The bench mark is 7.0 feet (2.1 m) below the level of
the track crimped to a galvanized steel rod and encased in a PVC pipe and
concrete kickblock.



                         BENCH MARK STAMPING:  5782 B 1978

MONUMENTATION:           Survey Disk                               VM#:     6068
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Galvanized Steel Rod


The bench mark is NE of the railroad trestle bridge over Shell Creek, 100.0 feet
(30.5 m) NE of Bench Mark 5782 A 1978, 16.3 feet (5.0 m) ESE of the east rail of
the track, 8.2 feet (2.5 m) feet (0.8 m) NE of a witness post.  The bench mark
is crimped to a galvanized steel rod driven 40 feet (12 m) to refusal, and
encased in a PVC pipe and concrete kickblock.

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

                                                   PUBLICATION DATE:  10/04/1984
Station ID: 8725782                                SUPERCEDED DATE:   04/21/2003
Name:       SEABOARD COASTLINE RAILROAD, SHELL CREEK          
            FLORIDA
NOAA Chart: 11426                                  Latitude:         26° 58.7' N
USGS Quad:  CLEVELAND                              Longitude:        81° 58.5' W


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


                         BENCH MARK STAMPING:  5782 C 1978

MONUMENTATION:           Survey Disk                               VM#:     6069
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Galvanized Steel Rod


The bench mark is NE along the track from the railroad trestle bridge over Shell
Creek, 231.0 feet (70.4 m) NNE of Bench Mark 5782 B 1978, 14.2 feet (4.3 m) ESE
of the east rail of the track, 7.5 feet (2.3 m) SE of the centerline of a dirt
track, and 2.2 feet (0.7 m) NW of a witness post.  The bench mark is  crimped to
a galvanized steel rod driven 40 feet (12 m) to refusal, and encased in a PVC
pipe and concrete kickblock.



                         BENCH MARK STAMPING:  5782 E 1978

MONUMENTATION:           Survey Disk                               VM#:     6070
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Galvanized Steel Rod


The bench mark is NE along the track from the railroad trestle bridge over Shell
lCreek, on the causeway where a spit of marsh juts to the NW, 420.0 feet (128.0
m) NE of Bench Mark 5782 C 1978, 9.2 feet (2.8 m) NW of the west rail of the
track, and 2.9 feet (0.9 m) SE of a witness post.  The bench mark is crimped to
a galvanized steel rod driven 40 feet (12 m) to refusal, and encased in a PVC
pipe and concrete kickblock.

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

                                                   PUBLICATION DATE:  10/04/1984
Station ID: 8725782                                SUPERCEDED DATE:   04/21/2003
Name:       SEABOARD COASTLINE RAILROAD, SHELL CREEK          
            FLORIDA
NOAA Chart: 11426                                  Latitude:         26° 58.7' N
USGS Quad:  CLEVELAND                              Longitude:        81° 58.5' W


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


                         BENCH MARK STAMPING:  5782 F 1978

MONUMENTATION:           Survey Disk                               VM#:     6071
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Galvanized Steel Rod


The bench mark is NE along the track from the railroad trestle bridge over Shell
Creek, 400.0 feet (121.9 m) NNE of Bench Mark 5782 E 1978, 63.0 feet (19.20 m)
NE of an overhead cable crossing the tracks, 14.3 feet (4.4 m) ESE of the east
rail ofthe track and 8.2 feet (2.50 m) ESE of the centerline of a dirt track. 
The bench mark is crimped to a galvanized steel rod driven 40 feet (12 m) to
refusal, and encased in a PVC, pipe and concrete kickblock.

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

                                                   PUBLICATION DATE:  10/04/1984
Station ID: 8725782                                SUPERCEDED DATE:   04/21/2003
Name:       SEABOARD COASTLINE RAILROAD, SHELL CREEK          
            FLORIDA
NOAA Chart: 11426                                  Latitude:         26° 58.7' N
USGS Quad:  CLEVELAND                              Longitude:        81° 58.5' W


                            T I D A L   D A T U M S 


Tidal datums at SEABOARD COASTLINE RAILROAD, SHELL CREEK based on:

     LENGTH OF SERIES:      3 MONTHS
     TIME PERIOD:           DECEMBER 1977-FEBRUARY 1978
     TIDAL EPOCH:           1960-1978
     CONTROL TIDE STATION:  8725744 PUNTA GORDA


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

     HIGHEST OBSERVED WATER LEVEL (05/04/1978)         =   3.87
     MEAN HIGHER HIGH WATER                     MHHW   =   2.17
     MEAN HIGH WATER                            MHW    =   1.91
     MEAN TIDE LEVEL                            MTL    =   1.18
     MEAN LOW WATER                             MLW    =   0.44
     MEAN LOWER LOW WATER                       MLLW   =   0.00
     LOWEST  OBSERVED WATER LEVEL (12/07/1977)         =  -1.07



Bench Mark Elevation Information                In FEET above:

     Stamping or Designation                    MLLW        MHW

     5782 A 1978                                 3.74      1.83
     5782 B 1978                                 9.27      7.36
     5782 C 1978                                 8.24      6.33
     5782 E 1978                                 7.38      5.47
     5782 F 1978                                 6.74      4.83


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

                                                   PUBLICATION DATE:  10/04/1984
Station ID: 8725782                                SUPERCEDED DATE:   04/21/2003
Name:       SEABOARD COASTLINE RAILROAD, SHELL CREEK          
            FLORIDA
NOAA Chart: 11426                                  Latitude:         26° 58.7' N
USGS Quad:  CLEVELAND                              Longitude:        81° 58.5' 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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