Superseded Bench Mark Sheet for 8726614, ALAFIA RIVER NORTH FL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:  08/07/1985
Station ID: 8726614                                SUPERCEDED DATE:   04/21/2003
Name:       ALAFIA RIVER NORTH                                
            FLORIDA
NOAA Chart: 11412                                  Latitude:         27° 52.2' N
USGS Quad:  BRANDON                                Longitude:        82° 19.2' W


To reach the tidal bench marks from the intersection of Riverview Drive and U.S.
Highway 301 in Riverview, proceed south on U.S. Highway 301 to Glen D. Litkes
Auto Salvage Company.  The bench marks are located near the Salvage Company. 
The tide gage and staff were located on the wooden dock behind the Salvage
Company.


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


                 PRIMARY BENCH MARK STAMPING:  6614 A 1977

MONUMENTATION:           Survey Disk                               VM#:     6623
AGENCY:                                                            PID#:  AG7481
SETTING CLASSIFICATION:  Concrete Bridge Abutment


The bench mark is at the NE corner of the bridge over the Alafia River, 26.4
feet (8.0 m) east of the centerline of U.S. Highway 301, 6 feet (2 m) east of
the east edge of the bridge, and 1.4 feet (0.4 m) west of the west edge of the
abutment foundation.



                         BENCH MARK STAMPING:  6614 B 1977

MONUMENTATION:           Survey Disk                               VM#:     6624
AGENCY:                                                            PID#:  AG7480
SETTING CLASSIFICATION:  Bridge Abutment


The bench mark is at the NW corner of the bridge over the Alafia River, 21.5
feet (6.6 m) west of the centerline of U.S. Highway 301, 6.1 feet (1.9 m) east
of the west end of the bridge abutment wingwall, and 0.7 feet (0.2 m) west of
the bridge rail.

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

                                                   PUBLICATION DATE:  08/07/1985
Station ID: 8726614                                SUPERCEDED DATE:   04/21/2003
Name:       ALAFIA RIVER NORTH                                
            FLORIDA
NOAA Chart: 11412                                  Latitude:         27° 52.2' N
USGS Quad:  BRANDON                                Longitude:        82° 19.2' W


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


                         BENCH MARK STAMPING:  6614 C 1977

MONUMENTATION:           Survey Disk                               VM#:     6625
AGENCY:                                                            PID#:  AG7482
SETTING CLASSIFICATION:  Concrete Post


The bench mark is just NE of the north end of the bridge, 61.5 feet (18.7 m) NE
of the SE corner of a wood frame house, 46.8 feet (14.3 m) west of a fence, 45
feet (14 m) north of north river bank, 41.5 feet (12.6 m) NNE of the north end
of a wooden walkway to a dock, 1.7 feet (0.5 m) south of the SE corner of a tin
building, and 1.3 feet (0.4 m) south of a witness post.  The bench mark is set
in the top of a concrete post.



                         BENCH MARK STAMPING:  6614 E 1977

MONUMENTATION:           Survey Disk                               VM#:     6626
AGENCY:                                                            PID#:  AG7479
SETTING CLASSIFICATION:  Concrete Curb


The bench mark is located in front of Glen Litkes property, 40.2 feet (12.3 m)
SW of the SW corner of a bike parts supply building, 37 feet (11 m) SW of a
power pole, and 26.8 feet (8.2 m) east of the centerline of U.S. Highway 301.



                         BENCH MARK STAMPING:  6614 F 1977

MONUMENTATION:           Survey Disk                               VM#:     6627
AGENCY:                                                            PID#:  AG7478
SETTING CLASSIFICATION:  Concrete Curb


The bench mark is located at the intersection of U.S. Highway 301 and Riverview
Drive, 41 feet (12 m) north of the centerline of Riverview Drive, 32.1 feet (9.8
m) east of the centerline of U.S. Highway 301, 23.6 feet (7.2 m) west of a
telephone pole, and 9 feet (3 m) WSW of traffic light pole # 0735.

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

                                                   PUBLICATION DATE:  08/07/1985
Station ID: 8726614                                SUPERCEDED DATE:   04/21/2003
Name:       ALAFIA RIVER NORTH                                
            FLORIDA
NOAA Chart: 11412                                  Latitude:         27° 52.2' N
USGS Quad:  BRANDON                                Longitude:        82° 19.2' W


                            T I D A L   D A T U M S 


Tidal datums at ALAFIA RIVER NORTH based on:

     LENGTH OF SERIES:      2 MONTHS
     TIME PERIOD:           March - April 1977
     TIDAL EPOCH:           1960-1978
     CONTROL TIDE STATION:  8726537 APOLLO BEACH


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

     HIGHEST OBSERVED WATER LEVEL (01/10/1977)         =   3.59
     MEAN HIGHER HIGH WATER                     MHHW   =   2.75
     MEAN HIGH WATER                            MHW    =   2.48
     MEAN TIDE LEVEL                            MTL    =   1.45
     MEAN LOW WATER                             MLW    =   0.42
     MEAN LOWER LOW WATER                       MLLW   =   0.00
     LOWEST  OBSERVED WATER LEVEL (02/02/1977)         =  -1.27

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In FEET above:

     Stamping or Designation                    MLLW        MHW

     6614 A 1977                                15.28     12.80
     6614 B 1977                                20.32     17.84
     6614 C 1977                                 7.16      4.68
     6614 E 1977                                14.56     12.08
     6614 F 1977                                16.78     14.30


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

                                                   PUBLICATION DATE:  08/07/1985
Station ID: 8726614                                SUPERCEDED DATE:   04/21/2003
Name:       ALAFIA RIVER NORTH                                
            FLORIDA
NOAA Chart: 11412                                  Latitude:         27° 52.2' N
USGS Quad:  BRANDON                                Longitude:        82° 19.2' 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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