Superseded Bench Mark Sheet for 8726467, MARSH BRANCH, RUSKIN FL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:  06/27/1985
Station ID: 8726467                                SUPERCEDED DATE:   04/21/2003
Name:       MARSH BRANCH, LITTLE MANATEE RIVER                
            FLORIDA
NOAA Chart: 11412                                  Latitude:         27° 43.1' N
USGS Quad:  RUSKIN                                 Longitude:        82° 27.2' W


To reach the tidal bench marks from the intersection of U.S. Highway 41 and
Shell Point Road, proceed 0.8 mile (1.3 km) west on Shell Point Road to Yost
Trailer Park.  The bench marks are located in the area around the trailer park. 
The tide gage and staff were located on a pier behind the trailer park.


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


                 PRIMARY BENCH MARK STAMPING:  6467 B 1977

MONUMENTATION:           Survey Disk                               VM#:     6508
AGENCY:                                                            PID#:  AG7515
SETTING CLASSIFICATION:  Concrete Seawall


The bench mark is 34.5 feet (10.5 m) south of the centerline of the paved road
around the trailer park, 18 feet (5 m) south of the north end of the boat ramp,
and 0.6 foot (0.2 m) west of the west edge of the boat ramp.



                         BENCH MARK STAMPING:  6467 C 1977

MONUMENTATION:           Survey Disk                               VM#:     6509
AGENCY:                                                            PID#:  AG7514
SETTING CLASSIFICATION:  Concrete Platform


The bench mark is at the SE corner of the boatlift, 28.5 feet (8.7 m) west of
the centerline of the paved road around the trailer park, 8.3 feet (2.5 m) east
of the center of the boatlift, and 1 foot (0.3 m) west of the east side of the
boatlift.

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

                                                   PUBLICATION DATE:  06/27/1985
Station ID: 8726467                                SUPERCEDED DATE:   04/21/2003
Name:       MARSH BRANCH, LITTLE MANATEE RIVER                
            FLORIDA
NOAA Chart: 11412                                  Latitude:         27° 43.1' N
USGS Quad:  RUSKIN                                 Longitude:        82° 27.2' W


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


                         BENCH MARK STAMPING:  6467 E 1977

MONUMENTATION:           Survey Disk                               VM#:     6510
AGENCY:                                                            PID#:  AG7513
SETTING CLASSIFICATION:  Copper-clad Steel Rod


The bench mark is 120 feet (37 m) NW of the NW corner of the Ruskin Drive-in
Restaurant, 26.5 feet (8.1 m) north of the centerline of Shell Point Road, 1.6
feet (0.5 m) east of utility pole #25, and 0.8 foot (0.2 m) south of a witness
post.  The bench mark is crimped to a copper-clad steel rod driven 40 feet (12
m) to refusal, and encased in a PVC pipe and concrete kickblock.



                         BENCH MARK STAMPING:  Y 261 1966

MONUMENTATION:           Survey Disk                               VM#:     6511
AGENCY:                                                            PID#:  AG6211
SETTING CLASSIFICATION:  Concrete Monument


The bench mark is set in the front of Yost Trailer Park, 140.0 feet (42.7 m) SW
of the SW corner of the Shop-and-Go grocery store, 26.2 feet (8.0 m) north of
the centerline of Shell Point Road, 1.2 feet (0.4 m) west of utility pole #27,
and 0.7 foot (0.2 m) south of a witness post.

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

                                                   PUBLICATION DATE:  06/27/1985
Station ID: 8726467                                SUPERCEDED DATE:   04/21/2003
Name:       MARSH BRANCH, LITTLE MANATEE RIVER                
            FLORIDA
NOAA Chart: 11412                                  Latitude:         27° 43.1' N
USGS Quad:  RUSKIN                                 Longitude:        82° 27.2' W


                            T I D A L   D A T U M S 


Tidal datums at MARSH BRANCH, LITTLE MANATEE RIVER based on:

     LENGTH OF SERIES:      2 MONTHS
     TIME PERIOD:           MARCH-APRIL 1977
     TIDAL EPOCH:           1960-1978
     CONTROL TIDE STATION:  8726520 ST. PETERSBURG


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

     HIGHEST OBSERVED WATER LEVEL (01/14/1977)         =   2.89
     MEAN HIGHER HIGH WATER                     MHHW   =   2.14
     MEAN HIGH WATER                            MHW    =   1.94
     MEAN TIDE LEVEL                            MTL    =   1.08
     MEAN LOW WATER                             MLW    =   0.23
     MEAN LOWER LOW WATER                       MLLW   =   0.00
     LOWEST  OBSERVED WATER LEVEL (03/01/1977)         =  -1.13

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In FEET above:

     Stamping or Designation                    MLLW        MHW

     6467 B 1977                                 3.76      1.82
     6467 C 1977                                 4.60      2.66
     6467 E 1977                                 5.84      3.90
     Y 261 1966                                  5.63      3.69


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

                                                   PUBLICATION DATE:  06/27/1985
Station ID: 8726467                                SUPERCEDED DATE:   04/21/2003
Name:       MARSH BRANCH, LITTLE MANATEE RIVER                
            FLORIDA
NOAA Chart: 11412                                  Latitude:         27° 43.1' N
USGS Quad:  RUSKIN                                 Longitude:        82° 27.2' 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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