Superseded Bench Mark Sheet for 8726667, Mckay Bay Entrance FL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:  06/29/2001
Station ID: 8726667                                SUPERCEDED DATE:   04/21/2003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#:  DL1851
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

                                                   PUBLICATION DATE:  06/29/2001
Station ID: 8726667                                SUPERCEDED 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#:  DL1806
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

                                                   PUBLICATION DATE:  06/29/2001
Station ID: 8726667                                SUPERCEDED 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

                                                   PUBLICATION DATE:  06/29/2001
Station ID: 8726667                                SUPERCEDED 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:      11 MONTHS
     TIME PERIOD:           January 1999 - November 1999
     TIDAL EPOCH:           1960-1978
     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)         =  2.203
     MEAN HIGHER HIGH WATER                     MHHW   =  0.816
     MEAN HIGH WATER                            MHW    =  0.720
     North American Vertical Datum              NAVD88 =  0.543
     MEAN SEA LEVEL                             MSL    =  0.440
     MEAN TIDE LEVEL                            MTL    =  0.431
     MEAN LOW WATER                             MLW    =  0.142
     MEAN LOWER LOW WATER                       MLLW   =  0.000
     LOWEST  OBSERVED WATER LEVEL (03/11/1996)         = -0.647

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     6667 J 1991                                 3.094    2.374
     6667 C 1976                                 3.158    2.438
     6667 E 1976                                 2.836    2.116
     6667 G 1990                                 2.901    2.181
     6667 H 1990                                 3.424    2.704


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

                                                   PUBLICATION DATE:  06/29/2001
Station ID: 8726667                                SUPERCEDED 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 (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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