Superseded Bench Mark Sheet for 8727648, HORSESHOE POINT FL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:  10/18/1984
Station ID: 8727648                                SUPERCEDED DATE:   04/21/2003
Name:       HORSESHOE POINT, HORSESHOE COVE                   
            FLORIDA
NOAA Chart: 11408                                  Latitude:         29° 26.2' N
USGS Quad:  HORSESHOE BEACH                        Longitude:        83° 17.6' W


To reach the tidal bench marks from the intersection of U.S. Highway 19-98 and
State Road C-351, proceed west on C-351 7.9 miles (12.7 km) to its inter-
section with C-357, continue SW on C-351 11.4 miles (18.3 km) to the Horseshoe
Point Post Office.  The bench marks are in area around Horseshoe Point and the
tide gage and staff were located on the Dockside Marina Pier.


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


                 PRIMARY BENCH MARK STAMPING:  7648 A 1978

MONUMENTATION:           Survey Disk                               VM#:     8220
AGENCY:                                                            PID#:  AR1635
SETTING CLASSIFICATION:  Concrete Foundation


The bench mark is set in the NW corner of a concrete porch at the Dockside
Marina, 37 feet (11 m) south of the centerline of C-351, 10 feet (3 m) north of
the NW corner of the building, 1.4 feet (0.4 m) south of the north edge of a
concrete porch, and 0.6 foot (0.2 m) east of the west edge of concrete.



                         BENCH MARK STAMPING:  HCB H 4 1961

MONUMENTATION:           Survey Disk                               VM#:     8219
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Concrete Post


The bench mark is 767 feet (234 m) NE of Bench Mark 7648 A 1978, 44 feet (13 m)
west of the canal, 25 feet (8 m) west of the centerline of C-351, 13 feet (4 m)
NE of Joes Cafe entrance, 3.5 feet (1.1 m) SE of the NE corner of the concrete
porch, 1.0 foot (0.3 m) east of the west edge of the concrete porch at the cafe,
and set in a concrete post.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  5

                                                   PUBLICATION DATE:  10/18/1984
Station ID: 8727648                                SUPERCEDED DATE:   04/21/2003
Name:       HORSESHOE POINT, HORSESHOE COVE                   
            FLORIDA
NOAA Chart: 11408                                  Latitude:         29° 26.2' N
USGS Quad:  HORSESHOE BEACH                        Longitude:        83° 17.6' W


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


                         BENCH MARK STAMPING:  SHELTON 1933

MONUMENTATION:           Survey Disk                               VM#:     8221
AGENCY:                                                            PID#:  AR1607
SETTING CLASSIFICATION:  Concrete Post


The bench mark is 134 feet (41 m) west of Bench Mark SHELTON NO 1 1933 in a
large pine thicket, 130 feet (40 m) west of the center of the dirt road, 47 feet
(14 m) south of an east-west dirt road that leads to the city park, 20 feet (6
m) south of the SE corner of a frame house, 2 feet (0.6 m) east of a lone cedar
bush, and set in a concrete post 0.5 foot (0.2 m) above ground level.



                         BENCH MARK STAMPING:  SHELTON NO 1 1933

MONUMENTATION:           Survey Disk                               VM#:     8222
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Concrete Post


The bench mark is 0.3 mile (0.5 km) south of the Horseshoe Point Post Office on
State Road C-351, then turn right for 0.1 mile (0.2 km), then left for 0.05 mile
(0.1 km) to the mark on the right side of the road, 98 feet (30 m) south of the
intersection of dirt roads, 57 feet (17.4 m) NW of the NW corner of a frame
house at the south intersection, 20 feet (6 m) east of a power pole, 8 feet (2
m) east of the centerline of the dirt road, and set in a concrete post.

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

                                                   PUBLICATION DATE:  10/18/1984
Station ID: 8727648                                SUPERCEDED DATE:   04/21/2003
Name:       HORSESHOE POINT, HORSESHOE COVE                   
            FLORIDA
NOAA Chart: 11408                                  Latitude:         29° 26.2' N
USGS Quad:  HORSESHOE BEACH                        Longitude:        83° 17.6' W


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


                         BENCH MARK STAMPING:  SHELTON AZIMUTH

MONUMENTATION:           Survey Disk                               VM#:     8223
AGENCY:                                                            PID#:  AR1608
SETTING CLASSIFICATION:  Concrete Post


The bench mark is 0.2 mile (0.3 km) south of the Horseshoe Point Post Office on
State Road C-351, 67 feet (20 m) west of the intersection of State Road C-351
and the road to Horseshoe Marina, 50 feet (15 m) NE of a frame house, 46 feet
(14 m) west of the centerline of C-351, and set in a concrete post 0.4 foot (0.1
m) above ground level.

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

                                                   PUBLICATION DATE:  10/18/1984
Station ID: 8727648                                SUPERCEDED DATE:   04/21/2003
Name:       HORSESHOE POINT, HORSESHOE COVE                   
            FLORIDA
NOAA Chart: 11408                                  Latitude:         29° 26.2' N
USGS Quad:  HORSESHOE BEACH                        Longitude:        83° 17.6' W


                            T I D A L   D A T U M S 


Tidal datums at HORSESHOE POINT, HORSESHOE COVE based on:

     LENGTH OF SERIES:      6 MONTHS
     TIME PERIOD:           JULY-DECEMBER 1978
     TIDAL EPOCH:           1960-1978
     CONTROL TIDE STATION:  8727520 CEDAR KEY


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

     HIGHEST OBSERVED WATER LEVEL (12/05/1978)         =   5.10
     MEAN HIGHER HIGH WATER                     MHHW   =   3.55
     MEAN HIGH WATER                            MHW    =   3.24
     MEAN TIDE LEVEL                            MTL    =   1.92
     MEAN LOW WATER                             MLW    =   0.59
     MEAN LOWER LOW WATER                       MLLW   =   0.00
     LOWEST  OBSERVED WATER LEVEL (10/15/1978)         =  -0.72

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In FEET above:

     Stamping or Designation                    MLLW        MHW

     7648 A 1978                                 7.74      4.50
     HCB H 4 1961                                8.49      5.25
     SHELTON 1933                                7.02      3.78
     SHELTON NO 1 1933                           6.81      3.57
     SHELTON AZIMUTH                             6.58      3.34


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

                                                   PUBLICATION DATE:  10/18/1984
Station ID: 8727648                                SUPERCEDED DATE:   04/21/2003
Name:       HORSESHOE POINT, HORSESHOE COVE                   
            FLORIDA
NOAA Chart: 11408                                  Latitude:         29° 26.2' N
USGS Quad:  HORSESHOE BEACH                        Longitude:        83° 17.6' 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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