Superseded Bench Mark Sheet for 8726045, HAYDEN ROBERTS BAY FL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:  08/31/1987
Station ID: 8726045                                SUPERCEDED DATE:   04/21/2003
Name:       HAYDEN, ROBERTS BAY                               
            FLORIDA
NOAA Chart: 11424                                  Latitude:         27° 17.5' N
USGS Quad:  SARASOTA                               Longitude:        82° 32.5' W


To reach the tidal bench marks from the intersection of U.S. Highway 41 and
State Highway 72, proceed north on U.S. Highway 41 for 2.35 miles (3.78 km) to
the junction of Kenilworth Street, then west on Kenilworth Street for 0.5 mile
(0.8 km) to the Reagle Lagoon Boat Basin.  The bench marks are located on the
seawall surrounding the boat basin.  The tide gage and staff were located at the
west end of a wooden dock SW of Bench Mark 6045 B 1977.


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


                 PRIMARY BENCH MARK STAMPING:  6045 A 1977

MONUMENTATION:           Survey Disk                               VM#:     6112
AGENCY:                                                            PID#:  AG7742
SETTING CLASSIFICATION:  Concrete Seawall


The bench mark is set flush in the top of the seawall, 28.8 feet (8.8 m) west of
the SW corner of a boat house, 19 feet (6 m) west of the end of the slip, 5.9
feet (1.8 m) NE of the NW corner of a boat hoist, and 0.7 foot (0.2 m) east of
the west edge of the seawall.



                         BENCH MARK STAMPING:  6045 B 1977

MONUMENTATION:           Survey Disk                               VM#:     6113
AGENCY:                                                            PID#:  AG7741
SETTING CLASSIFICATION:  Concrete Seawall


The bench mark is set flush in the top of the seawall, 30.0 feet (9.1 m) SW of
the SW corner of a boat house, 17.7 feet (5.4 m) west of the end of the slip,
12.0 feet (3.7 m) south of Bench Mark 6045 A 1977, and 0.6 foot (0.2 m) east of
the west edge of the seawall.

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

                                                   PUBLICATION DATE:  08/31/1987
Station ID: 8726045                                SUPERCEDED DATE:   04/21/2003
Name:       HAYDEN, ROBERTS BAY                               
            FLORIDA
NOAA Chart: 11424                                  Latitude:         27° 17.5' N
USGS Quad:  SARASOTA                               Longitude:        82° 32.5' W


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


                         BENCH MARK STAMPING:  6045 C 1977

MONUMENTATION:           Survey Disk                               VM#:     6114
AGENCY:                                                            PID#:  AG7740
SETTING CLASSIFICATION:  Concrete Seawall


The bench mark is set flush in the top of the seawall, 150.0 feet (45.7 m) east
of Bench Mark 6045 B 1977, 71.0 feet (21.6 m) SW of the end of a drive, 61.8
feet (18.8 m) SE of the SE corner of a boat house, and 0.5 foot (0.2 m) north of
the south edge of the seawall.



                         BENCH MARK STAMPING:  6045 E 1977

MONUMENTATION:           Survey Disk                               VM#:     6115
AGENCY:                                                            PID#:  AG7739
SETTING CLASSIFICATION:  Concrete Seawall


The bench mark is set flush in the top of the seawall, 104.0 feet (31.7 m) east
of Bench Mark 6045 C 1977, 70.7 feet (21.5 m) SW of a power pole, 16.0 feet (4.9
m) south of the centerline of a drive, and 0.4 foot (0.1 m) north of the south
edge of the seawall.



                         BENCH MARK STAMPING:  6045 F 1977

MONUMENTATION:           Survey Disk                               VM#:     6116
AGENCY:                                                            PID#:  AG7738
SETTING CLASSIFICATION:  Concrete Seawall


The bench mark is set flush in the top of the seawall, 92.0 feet (28.0 m) east
of Bench Mark 6045 E 1977, 38.0 feet (11.6 m) SE of power pole #1321, and 0.5
foot (0.2 m) north of the south edge of the seawall.

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

                                                   PUBLICATION DATE:  08/31/1987
Station ID: 8726045                                SUPERCEDED DATE:   04/21/2003
Name:       HAYDEN, ROBERTS BAY                               
            FLORIDA
NOAA Chart: 11424                                  Latitude:         27° 17.5' N
USGS Quad:  SARASOTA                               Longitude:        82° 32.5' W


                            T I D A L   D A T U M S 


Tidal datums at HAYDEN, ROBERTS BAY based on:

     LENGTH OF SERIES:      2 MONTHS
     TIME PERIOD:           JUNE-JULY 1977
     TIDAL EPOCH:           1960-1978
     CONTROL TIDE STATION:  8726247 BRADENTON, MANATEE RIVER


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

     HIGHEST OBSERVED WATER LEVEL (06/03/1977)         =   3.15
     MEAN HIGHER HIGH WATER                     MHHW   =   2.02
     MEAN HIGH WATER                            MHW    =   1.75
     MEAN TIDE LEVEL                            MTL    =   1.02
     MEAN LOW WATER                             MLW    =   0.29
     MEAN LOWER LOW WATER                       MLLW   =   0.00
     LOWEST  OBSERVED WATER LEVEL (04/28/1977)         =  -0.51

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In FEET above:

     Stamping or Designation                    MLLW        MHW

     6045 A 1977                                 5.12      3.37
     6045 B 1977                                 5.06      3.31
     6045 C 1977                                 4.21      2.46
     6045 E 1977                                 4.14      2.39
     6045 F 1977                                 3.98      2.23


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

                                                   PUBLICATION DATE:  08/31/1987
Station ID: 8726045                                SUPERCEDED DATE:   04/21/2003
Name:       HAYDEN, ROBERTS BAY                               
            FLORIDA
NOAA Chart: 11424                                  Latitude:         27° 17.5' N
USGS Quad:  SARASOTA                               Longitude:        82° 32.5' 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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