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Superseded Bench Mark Sheet for 8725769, EL JOBEAN, MYAKKA RIVER FL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:  10/22/1984
Station ID: 8725769                                SUPERCEDED DATE:   04/21/2003
Name:       EL JOBEAN, MYAKKA RIVER                           
            FLORIDA
NOAA Chart: 11426                                  Latitude:         26° 57.7' N
USGS Quad:  EL JOBEAN                              Longitude:        82° 12.6' W


To reach the tidal bench marks, in Sarasota, Florida, proceed to Federal Route
41, go south on Federal Route 41 south 5.0 miles (8.0 km) pass its intersection
with State Route 72 to State Road 771 follow this road 10 miles (16.1 km) to the
bridge.  The bench marks are along bridge.  The tide gage and staff were located
under railroad bridge at south end of north bridge section.


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


                 PRIMARY BENCH MARK STAMPING:  5769 A 1977

MONUMENTATION:           Survey Disk                               VM#:     6054
AGENCY:                                                            PID#:  AG7765
SETTING CLASSIFICATION:  Seawall


The bench mark is at north end of bridge over the Myakka River, 148.0 feet (45.1
m) north of Bench Mark 5769 B 1977, 42.0 feet (12.8 m) east of centerline of
Highway 45, 1.5 feet (0.5 m) south of north end of seawall, and set in top of
the seawall.



                         BENCH MARK STAMPING:  5769 B 1977

MONUMENTATION:           Survey Disk                               VM#:     6055
AGENCY:                                                            PID#:  AG7766
SETTING CLASSIFICATION:  Seawall


The bench mark is at the north end of the bridge oer the Myakka River, 192.0
feet (58.5 m) north of Bench Mark 5769 C 1977, 148.0 feet (45.1 m) south of
Bench Mark 5769 A 1977, 42.0 feet (12.8 m) east of centerline of Highway 771
(alt. 45) and 1.0 foot (0.3 m) west of east edge of seawall, and is set in top
of the seawall.

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

                                                   PUBLICATION DATE:  10/22/1984
Station ID: 8725769                                SUPERCEDED DATE:   04/21/2003
Name:       EL JOBEAN, MYAKKA RIVER                           
            FLORIDA
NOAA Chart: 11426                                  Latitude:         26° 57.7' N
USGS Quad:  EL JOBEAN                              Longitude:        82° 12.6' W


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


                         BENCH MARK STAMPING:  5769 C 1977

MONUMENTATION:           Survey Disk                               VM#:     6056
AGENCY:                                                            PID#:  AG7767
SETTING CLASSIFICATION:  Seawall


The bench mark is at the north end of the bridge over the Myakka River, 192.0
feet (58.5 m) south of Bench Mark 5769 B 1977, 175.0 feet (53.3 m) NE of S.R.D.
Bench Mark, 43.0 feet (13.1 m) east of centerline of Highway 771 (alt. 45), 20.0
feet (6.1 m) east of east curb of Highway 771 (alt. 45) and 1.0 foot (0.3 m)
west of east edge of seawall, and is set in top of the seawall.



                         BENCH MARK STAMPING:  UNSTAMPED

MONUMENTATION:           Survey Disk                               VM#:     6057
AGENCY:                                                            PID#:  AG7769
SETTING CLASSIFICATION:  Concrete Banister


The bench mark is set in banister of bridge on west side of north end of bridge
over the Myakka River, 175.0 feet (53.3 m) southwest of Bench Mark 5769 C 1977,
19.0 feet (5.8 m) west of centerline of Highway 771 (alt. 45) and 4.0 feet (1.2
m) west of west curb and walkway on bridge.



                         BENCH MARK STAMPING:  MYAKKA 1981

MONUMENTATION:           Survey Disk                               VM#:     6058
AGENCY:                                                            PID#:  AG7768
SETTING CLASSIFICATION:  Sidewalk


The bench mark is set into sidewalk of bridge on the north side of the east end
of the bridge over the Myakka River, 8.5 feet (2.6 m) north of Florida S.R.D.
Bench Mark, 4.5 feet (1.4 m) west of street edge of curb and 2.9 feet (0.9 m)
east of the Myakka River sign.

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

                                                   PUBLICATION DATE:  10/22/1984
Station ID: 8725769                                SUPERCEDED DATE:   04/21/2003
Name:       EL JOBEAN, MYAKKA RIVER                           
            FLORIDA
NOAA Chart: 11426                                  Latitude:         26° 57.7' N
USGS Quad:  EL JOBEAN                              Longitude:        82° 12.6' W


                            T I D A L   D A T U M S 


Tidal datums at EL JOBEAN, MYAKKA RIVER based on:

     LENGTH OF SERIES:      5 MONTHS
     TIME PERIOD:           AUG. - DEC. 1977
     TIDAL EPOCH:           1960-1978
     CONTROL TIDE STATION:  8725744 PUNTA GORDA


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

     HIGHEST OBSERVED WATER LEVEL (09/26/1977)         =   3.05
     MEAN HIGHER HIGH WATER                     MHHW   =   2.05
     MEAN HIGH WATER                            MHW    =   1.78
     MEAN TIDE LEVEL                            MTL    =   1.11
     MEAN LOW WATER                             MLW    =   0.44
     MEAN LOWER LOW WATER                       MLLW   =   0.00
     LOWEST  OBSERVED WATER LEVEL (11/11/1977)         =  -1.28

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In FEET above:

     Stamping or Designation                    MLLW        MHW

     5769 A 1977                                 4.66      2.88
     5769 B 1977                                 4.69      2.91
     5769 C 1977                                 4.65      2.87
     UNSTAMPED                                  19.16     17.38
     MYAKKA 1981                                15.74     13.96


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

                                                   PUBLICATION DATE:  10/22/1984
Station ID: 8725769                                SUPERCEDED DATE:   04/21/2003
Name:       EL JOBEAN, MYAKKA RIVER                           
            FLORIDA
NOAA Chart: 11426                                  Latitude:         26° 57.7' N
USGS Quad:  EL JOBEAN                              Longitude:        82° 12.6' 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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Revised: 08/08/2018
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