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Station ID: 8725782 SUPERCEDED DATE: 04/21/2003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Station ID: 8725782 SUPERCEDED DATE: 04/21/2003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.