U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 8726667 PUBLICATION DATE: 04/21/2003
Name: CSX ROCKPORT, MCKAY BAY ENTRANCE
FLORIDA
NOAA Chart: 11412 Latitude: 27° 54.8' N
USGS Quad: TAMPA Longitude: 82° 25.5' W
To reach the tidal bench marks from the intersection of U.S. Highway 41 and
Causeway Boulevard (U.S. Business 41), proceed west on Causeway Boulevard for
1.6 km (1.0 mi) to the access road for Rockport Terminal, then go south on the
access road for 1.1 km (0.7 mi) to the Rockport Terminal. The bench marks are
located around the terminal between the loading dock and railroad tracks. The
tide gauge is located at the south end of the loading dock west of the conveyor
building.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 6667 J 1991
DESIGNATION: 872 6667 J
MONUMENTATION: Tidal Station disk VM#: 6825
AGENCY: National Ocean Service (NOS) PID:
SETTING CLASSIFICATION: Concrete foundation
The primary bench mark is a disk set in the SW corner of the concrete foundation
of a stop for the bulk loader that travels on rails along the waterfront, 18.41
m (60.4 ft) NE of the NE corner of the concrete walkway leading to the dock,
3.72 m (12.2 ft) WNW of the west rail of the bulk loader, and 0.91 m (3.0 ft)
WSW of the SW corner of the stop.
BENCH MARK STAMPING: 6667 C 1976
DESIGNATION: 872 6667 C TIDAL
MONUMENTATION: Tidal Station disk VM#: 6820
AGENCY: National Ocean Survey (NOS) PID#: AG7506
SETTING CLASSIFICATION: Concrete porch
The bench mark is a disk set on the concrete porch located along the SE wall of
the Seaboard Coastline Railroad terminal office, SE of the boat mooring area,
75.3 m (247.0 ft) west of bench mark 6667 E 1976, 7.99 m (26.2 ft) SW of the
east corner of the building, and 0.85 m (2.8 ft) SE of the SE wall of the
building.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 8726667 PUBLICATION DATE: 04/21/2003
Name: CSX ROCKPORT, MCKAY BAY ENTRANCE
FLORIDA
NOAA Chart: 11412 Latitude: 27° 54.8' N
USGS Quad: TAMPA Longitude: 82° 25.5' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 6667 E 1976
DESIGNATION: 872 6667 E
MONUMENTATION: Tidal Station disk VM#: 6821
AGENCY: National Ocean Survey (NOS) PID:
SETTING CLASSIFICATION: Copper-clad steel rod
The bench mark is a disk located at power pole #11 north of the paved access
road leading to the boat landing area at Rockport Terminal, 183 m (600 ft) west
of bench mark 6667 F 1976, 6.7 m (22.0 ft) north of the centerline of the access
road, and 2.01 m (6.6 ft) east of the east face power pole #11. The bench mark
is just below ground level, crimped to a copper clad steel rod driven to an
unspecified depth, and encased in a PVC pipe with concrete kickblock.
BENCH MARK STAMPING: 6667 G 1990
DESIGNATION: 872 6667 G
MONUMENTATION: Tidal Station disk VM#: 6823
AGENCY: National Ocean Service (NOS) PID:
SETTING CLASSIFICATION: Mooring bollard base
The bench mark is a disk set in the SW corner of the concrete base of a mooring
bollard located near the NE end of the loading dock, 28.29 m (92.8 ft) NW of the
NW corner of the restroom building, 23.9 m (78.4 ft) NW of power pole
#2636940260, 2.80 m (9.2 ft) north of the centerline of the concrete ramp
leading to the dock, 1.98 m (6.5 ft) west of the top edge of the riprap sea
wall, and 0.18 m (0.6 ft) above ground.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 8726667 PUBLICATION DATE: 04/21/2003
Name: CSX ROCKPORT, MCKAY BAY ENTRANCE
FLORIDA
NOAA Chart: 11412 Latitude: 27° 54.8' N
USGS Quad: TAMPA Longitude: 82° 25.5' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 6667 H 1990
DESIGNATION: 872 6667 H
MONUMENTATION: Tidal Station disk VM#: 6824
AGENCY: National Ocean Service (NOS) PID:
SETTING CLASSIFICATION: Concrete foundation
The bench mark is a disk set in the SE corner of the concrete foundation of a
steel arm structure located at the railroad unloading building, 12.56 m (41.2
ft) west of the centerline of the access road, 7.77 m (25.5 ft) NE of the NE
corner of the railroad unloading building, 6.7 m (22.0 ft) east of power pole
#3644540245, and 0.15 m (0.5 ft) above ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 8726667 PUBLICATION DATE: 04/21/2003
Name: CSX ROCKPORT, MCKAY BAY ENTRANCE
FLORIDA
NOAA Chart: 11412 Latitude: 27° 54.8' N
USGS Quad: TAMPA Longitude: 82° 25.5' W
T I D A L D A T U M S
Tidal datums at CSX ROCKPORT, MCKAY BAY ENTRANCE based on:
LENGTH OF SERIES: 3 Years
TIME PERIOD: January 1999 - December 2001
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8726520 ST. PETERSBURG, TAMPA BAY
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
HIGHEST OBSERVED WATER LEVEL (10/08/1996) = 2.131
MEAN HIGHER HIGH WATER (MHHW) = 0.821
MEAN HIGH WATER (MHW) = 0.722
NORTH AMERICAN VERTICAL DATUM-1988 (NAVD) = 0.471
MEAN SEA LEVEL (MSL) = 0.444
MEAN TIDE LEVEL (MTL) = 0.434
MEAN LOW WATER (MLW) = 0.147
MEAN LOWER LOW WATER (MLLW) = 0.000
LOWEST OBSERVED WATER LEVEL (03/11/1996) = -0.719
National Geodetic Vertical Datum (NGVD 29)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
6667 J 1991 3.022 2.300
6667 C 1976 3.086 2.364
6667 E 1976 2.764 2.042
6667 G 1990 2.829 2.107
6667 H 1990 3.352 2.630
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 8726667 PUBLICATION DATE: 04/21/2003
Name: CSX ROCKPORT, MCKAY BAY ENTRANCE
FLORIDA
NOAA Chart: 11412 Latitude: 27° 54.8' N
USGS Quad: TAMPA Longitude: 82° 25.5' 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 (NAVD 88).
NGVD 29 is a fixed datum adopted as a national standard geodetic reference for
heights but is now considered superseded. NGVD 29 is sometimes referred to as
Sea Level Datum of 1929 or as Mean Sea Level on some early issues of Geological
Survey Topographic Quads. NGVD 29 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 NGVD 29 are available from the National
Geodetic Survey (NGS) data base via the World Wide Web at
National Geodetic Survey.
NAVD 88 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. NAVD 88 replaces NGVD 29 as the national
standard geodetic reference for heights. Bench mark elevations relative to
NAVD 88 are available from NGS through the World Wide Web at
National Geodetic Survey.
NGVD 29 and NAVD 88 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 NAVD 88 elevation is shown on the Elevations of Tidal Datums Table Referred
to MLLW only when two or more of the bench marks listed have NAVD 88 elevations.
The NAVD 88 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, NAVD 88 bench mark elevations computed indirectly from the tidal
datums elevation table may differ slightly from NAVD 88 elevations listed for
each bench mark in the NGS database.