Superseded Bench Mark Sheet for 8726761, DUNEDIN CITY DOCK FL

Present Epoch

Printable version

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  4

                                                   PUBLICATION DATE:  11/04/1995
Station ID: 8726761                                SUPERCEDED DATE:   04/21/2003
Name:       DUNEDIN, CLEARWATER HARBOR                        
            FLORIDA
NOAA Chart: 11412                                  Latitude:         28°  0.8' N
USGS Quad:  DUNEDIN                                Longitude:        82° 47.6' W


To reach the tidal bench marks from the intersection of Main Street and
Edgewater Drive in Dunedin, proceed west on main Street to its end at the city
dock.  The bench marks are located along Main Street and Victoria Drive.  The
tide gage and staff were located at the west end of the city dock at the foot of
Main Street.


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


                 PRIMARY BENCH MARK STAMPING:  6 1973

MONUMENTATION:           Survey Disk                               VM#:     7568
AGENCY:                                                            PID#:  AL0401
SETTING CLASSIFICATION:  Sea Wall


The bench mark is set flush in top of a 2 foot (1 m) thick concrete sea wall on
the south side of Main Street across from the Jamaica Inn, on the north side of
the Dunedin Yacht Basin, 105 feet (32 m) east of the basin entrance, 10 feet (3
m) south of the north corner of a jog in the sea wall, and 0.8 foot (0.2 m)
above the pavement.



                         BENCH MARK STAMPING:  NO 4

MONUMENTATION:           Survey Disk                               VM#:     7569
AGENCY:                                                            PID#:  AL6288
SETTING CLASSIFICATION:  Curb


The bench mark is set in the top of the east curb of Victoria Drive, 268 feet
(82 m) north of the centerline of Main Street, 162 feet (49 m)  south of the
centerline of Monroe Street, 16.5 feet (5.0 m) north of the centerline of a
sidewalk leading to the house at 821 Victoria Drive, and 9 feet (3 m) east of
the centerline of Victoria Drive.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  4

                                                   PUBLICATION DATE:  11/04/1995
Station ID: 8726761                                SUPERCEDED DATE:   04/21/2003
Name:       DUNEDIN, CLEARWATER HARBOR                        
            FLORIDA
NOAA Chart: 11412                                  Latitude:         28°  0.8' N
USGS Quad:  DUNEDIN                                Longitude:        82° 47.6' W


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


                         BENCH MARK STAMPING:  NO III

MONUMENTATION:           Survey Disk                               VM#:     7570
AGENCY:                                                            PID#:  AL6289
SETTING CLASSIFICATION:  Sidewalk


The bench mark is set in top of the old sea wall in the center of the sidewalk
at the west end of Main Street, by the east end of the fishing pier leading to
Dunedin Fish Company Store, 95 feet (29 m) west of the centerline of Victoria
Drive on the south/SE portion of the Jamaica Inn Motel property, 29 feet (9 m)
north of the centerline of Main Street, and 3 feet (1 m) south of a concrete
block wall.



                         BENCH MARK STAMPING:  115 SRD

MONUMENTATION:           Survey Disk                               VM#:     7571
AGENCY:                                                            PID#:  AL0007
SETTING CLASSIFICATION:  Concrete Abutment


The bench mark is set in the top center of a 0.5 foot (0.2 m) thick concrete
abutment of a culvert, at the intersection of Monroe Street and Victoria Drive,
30 feet (9 m) west of the centerline of Victoria Drive, 27 feet (8 m) south of
the north end of the abutment, 3 feet (1 m) north of the south end, and 4 feet
(1 m) below road level.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  4

                                                   PUBLICATION DATE:  11/04/1995
Station ID: 8726761                                SUPERCEDED DATE:   04/21/2003
Name:       DUNEDIN, CLEARWATER HARBOR                        
            FLORIDA
NOAA Chart: 11412                                  Latitude:         28°  0.8' N
USGS Quad:  DUNEDIN                                Longitude:        82° 47.6' W


                            T I D A L   D A T U M S 


Tidal datums at DUNEDIN, CLEARWATER HARBOR based on:

     LENGTH OF SERIES:      33 MONTHS
     TIME PERIOD:           1973-1976
     TIDAL EPOCH:           1960-1978
     CONTROL TIDE STATION:  8726724 CLEARWATER BEACH


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

     HIGHEST OBSERVED WATER LEVEL (07/12/1975)         =   4.77
     MEAN HIGHER HIGH WATER                     MHHW   =   2.89
     MEAN HIGH WATER                            MHW    =   2.55
     MEAN TIDE LEVEL                            MTL    =   1.54
     MEAN LOW WATER                             MLW    =   0.54
     MEAN LOWER LOW WATER                       MLLW   =   0.00
     LOWEST  OBSERVED WATER LEVEL (02/05/1974)         =  -1.53

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In FEET above:

     Stamping or Designation                    MLLW        MHW

     6 1973                                      6.14      3.59
     NO 4                                        8.49      5.94
     NO III                                      6.71      4.16
     115 SRD                                     5.38      2.83


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

                                                   PUBLICATION DATE:  11/04/1995
Station ID: 8726761                                SUPERCEDED DATE:   04/21/2003
Name:       DUNEDIN, CLEARWATER HARBOR                        
            FLORIDA
NOAA Chart: 11412                                  Latitude:         28°  0.8' N
USGS Quad:  DUNEDIN                                Longitude:        82° 47.6' 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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