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Bench Mark Sheet for 8726774, CALADESI ISLAND, INSIDE FL

Superseded Epoch

Large map location marker Station Location
Small red map location marker Published bench mark
Small blue map location marker Unpublished bench mark

Bench mark positions only appear on the map if their coordinates in the CO-OPS database are at the precision of degrees/minutes/seconds/and tenths of seconds. If the coordinates are less precise, the mark will not appear.

Printable version

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  5

                                                                                
Station ID: 8726774                         PUBLICATION DATE:  04/29/2004
Name:       CALADESI ISLAND, INSIDE                           
            FL
NOAA Chart: 11412                           Latitude:   28°  1.9' N (  28.03170)
USGS Quad:  DUNEDIN                         Longitude:  82° 49.2' W ( -82.82000)


To reach the tidal bench marks from Dunedin City Marina, proceed by boat or
ferry to Caladesi Island State Park.  The bench marks are located around the
State Park.  The tide gage and staff were located on the pier behind the boat
house.


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


                 PRIMARY BENCH MARK STAMPING:  6774 C 1976
                         DESIGNATION:          872 6774 C

MONUMENTATION:           Tidal Station disk                    VM#:         7587
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   28°  1.9' N (  28.03170)          LONGITUDE:  82° 49.2' W ( -82.82000)


The primary bench mark is a disk located 19.57 m (64.2 ft) south of the SW
corner of a boat basin, and 0.64 m (2.1 ft) south of power pole #210752.  The
bench mark is level with the ground, crimped to a copper-clad steel rod driven
an unspecified depth 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

                                                                                
Station ID: 8726774                         PUBLICATION DATE:  04/29/2004
Name:       CALADESI ISLAND, INSIDE                           
            FL
NOAA Chart: 11412                           Latitude:   28°  1.9' N (  28.03170)
USGS Quad:  DUNEDIN                         Longitude:  82° 49.2' W ( -82.82000)


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


                         BENCH MARK STAMPING:  6774 D 1976
                         DESIGNATION:          872 6774 D

MONUMENTATION:           Tidal Station disk                    VM#:         7588
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   28°  1.9' N (  28.03170)          LONGITUDE:  82° 49.2' W ( -82.82000)


The bench mark is a disk located 15.48 m (50.8 ft) west of the NW corner of the
marina basin.  The bench mark is 0.61 m (2.0 ft) below ground level, crimped to
the top of a copper-clad steel rod driven an unspecified depth to refusal, and
encased in a PVC pipe and concrete kickblock.  NOTE: The mark was searched for
but not found by FLDNR in 1983.  The area is buried under about 1 m (3 ft) of
fill.

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

                                                                                
Station ID: 8726774                         PUBLICATION DATE:  04/29/2004
Name:       CALADESI ISLAND, INSIDE                           
            FL
NOAA Chart: 11412                           Latitude:   28°  1.9' N (  28.03170)
USGS Quad:  DUNEDIN                         Longitude:  82° 49.2' W ( -82.82000)


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


                         BENCH MARK STAMPING:  R23 1974
                         DESIGNATION:          R23

MONUMENTATION:           Survey disk                           VM#:         7589
AGENCY:                  Florida Department of Natural Resources
                         (FLDNR)                               IDB PID#:        
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   28°  1.9' N (  28.03170)          LONGITUDE:  82° 49.2' W ( -82.82000)


The bench mark is a disk set in the top of a concrete monument, 88 m (288 ft)
west of Bench Mark 6774 D 1976, 17.13 m (56.2 ft) west of a sand dune
information sign, 0.76 m (2.5 ft) ESE of a metal witness post, and at ground
level.



                         BENCH MARK STAMPING:  6774 A 1976
                         DESIGNATION:          872 6774 A

MONUMENTATION:           Tidal Station disk                    VM#:        17161
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Concrete pad                          OPUS PID:        
LATITUDE:   28°  1.9' N (  28.03170)          LONGITUDE:  82° 49.2' W ( -82.82000)


The bench mark is a disk set in the concrete pad for the eastern boat davit at
the boat house, 1.98 m (6.5 ft) NW of the corner of a 2 m (6 ft) high fence,
1.43 m (4.7 ft) south of the sea wall, and 0.55 m (1.8 ft) east of the SE brace
for the davit.  NOTE:  The mark was destroyed by the construction of a new sea
wall, 7/1/1980.

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

                                                                                
Station ID: 8726774                         PUBLICATION DATE:  04/29/2004
Name:       CALADESI ISLAND, INSIDE                           
            FL
NOAA Chart: 11412                           Latitude:   28°  1.9' N (  28.03170)
USGS Quad:  DUNEDIN                         Longitude:  82° 49.2' W ( -82.82000)


                            T I D A L   D A T U M S 


Tidal datums at CALADESI ISLAND, INSIDE based on:

     LENGTH OF SERIES:      1 MONTH
     TIME PERIOD:           March 1976 - March 1976
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  8726724 CLEARWATER BEACH, GULF OF MEXICO


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

     MEAN HIGHER HIGH WATER                     MHHW   =  0.880
     MEAN HIGH WATER                            MHW    =  0.773
     MEAN SEA LEVEL                             MSL    =  0.468
     MEAN TIDE LEVEL                            MTL    =  0.465
     MEAN LOW WATER                             MLW    =  0.157
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     6774 C 1976                                 1.666    0.893
     6774 D 1976                                 2.085    1.312
     R23 1974                                    1.954    1.181
     6774 A 1976                                 1.684    0.911


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

                                                                                
Station ID: 8726774                         PUBLICATION DATE:  04/29/2004
Name:       CALADESI ISLAND, INSIDE                           
            FL
NOAA Chart: 11412                           Latitude:   28°  1.9' N (  28.03170)
USGS Quad:  DUNEDIN                         Longitude:  82° 49.2' W ( -82.82000)


                             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 NGS's Integrated Data Base (IDB PID)
provides geodetic datum based on traditionally leveled and bluebooked ties to
the National Spatial Reference System(NSRS) https://www.ngs.noaa.gov/datasheets/.
The NGS Online Positioning User Service (OPUS PID) provides geodetic datum based
on GPS position & tie it to the NSRS https://www.ngs.noaa.gov/OPUS/.

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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Revised: 08/08/2018
NOAA / National Ocean Service
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