Superseded Bench Mark Sheet for 8729071, MILL BAYOU, NORTH BAY FL

Present Epoch

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                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  4

                                                   PUBLICATION DATE:  12/09/1987
Station ID: 8729071                                SUPERCEDED DATE:   04/21/2003
Name:       MILL BAYOU, NORTH BAY                             
            FLORIDA
NOAA Chart: 11390                                  Latitude:         30° 14.7' N
USGS Quad:  SPRINGFIELD                            Longitude:        85° 36.3' W


To reach the tidal bench marks from Lynn Haven, proceed from the intersection of
County Road 389 with State Road 77, 1.3 miles (2.1 km) east on County Road 389
to 12th Street, 0.9 mile (1.4 km) east on 12th Street to its end at Harvard
Boulevard, 0.3 mile (0.5 km) north on Harvard Boulevard to its intersection with
9th Street, 0.3 mile (0.5 km) east on 9th Street to the road fork of Feral Lane,
and then left on Feral Lane for 0.35 mile (0.56 km).  The bench marks are
primarily along Feral Lane.  The tide gage and staff were located on a pier on
the property to the north of 2963 Feral Lane.


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


                 PRIMARY BENCH MARK STAMPING:  9071 A 1976

MONUMENTATION:           Survey Disk                               VM#:     9968
AGENCY:                                                            PID#:  BE2970
SETTING CLASSIFICATION:  Copper-clad Steel Rod


The bench mark is located at 2643 Feral Lane, 156.6 feet (47.7 m) north of Bench
Mark 9071 D 1976, 32.4 feet (9.9 m) south of the centerline of the drive leading
to the residence, 27.6 feet (8.4 m) east of the centerline of Feral Drive, 1.6
feet (0.5 m) west of a property corner marker, and 1.0 foot (0.3 m) west of a
witness post.  The bench mark is 0.2 foot (0.1 m) above ground level, crimped to
a copper-clad steel rod driven 40 feet (12 m), and encased in a PVC pipe and
concrete kickblock.



                         BENCH MARK STAMPING:  9071 B 1976

MONUMENTATION:           Survey Disk                               VM#:     9969
AGENCY:                                                            PID#:  BE2972
SETTING CLASSIFICATION:  Copper-clad Steel Rod


The bench mark is located at 2643 Feral Lane, 319 feet (97 m) east of the
centerline of Feral Lane, 292.5 feet (89.2 m) east of Bench Mark 9071 A 1976,
66.3 feet (20.2 m) SE of the SE corner of the house, 21 feet (6 m) east of a
lone palm tree, 5.4 feet (1.6 m) WSW of a 14-inch diameter pine tree, and 0.5
foot (0.2 m) SW of a witness post.  The bench mark is 0.2 foot (0.1 m) above
ground level, crimped to a copper-clad steel rod driven to an unspecified depth
to refusal, and encased in a PVC pipe and concrete kickblock.

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

                                                   PUBLICATION DATE:  12/09/1987
Station ID: 8729071                                SUPERCEDED DATE:   04/21/2003
Name:       MILL BAYOU, NORTH BAY                             
            FLORIDA
NOAA Chart: 11390                                  Latitude:         30° 14.7' N
USGS Quad:  SPRINGFIELD                            Longitude:        85° 36.3' W


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


                         BENCH MARK STAMPING:  9071 C 1976

MONUMENTATION:           Survey Disk                               VM#:     9970
AGENCY:                                                            PID#:  BE2969
SETTING CLASSIFICATION:  Concrete Pad


The bench mark is set flush in the SW corner of a 3-foot (1 m) by 3-foot (1 m)
square concrete base for a transformer, 196.0 feet (59.7 m) NNE of Bench Mark
9071 A 1976, 165 feet (50 m) north of the drive to 2643 Feral Lane, 94.2 feet
(28.7 m) south of a metal culvert, and 17.4 feet (5.3 m) east of the centerline
of Feral Lane.



                         BENCH MARK STAMPING:  9071 D 1976

MONUMENTATION:           Survey Disk                               VM#:     9971
AGENCY:                                                            PID#:  BE2971
SETTING CLASSIFICATION:  Concrete Pad


The bench mark is set flush in the NW corner of a concrete base for a
transformer, 37.5 feet (11.4 m) NW of the centerline of the drive leading to
2963 Feral Lane, 19.8 feet (6.0 m) east of the centerline of Feral Lane, 5.4
feet (1.6 m) NNW of a property corner marker, and 3.4 feet (1.0 m) east of the
west corner of the pad.



                         BENCH MARK STAMPING:  9071 E 1984

MONUMENTATION:           Survey Disk                               VM#:     9972
AGENCY:                                                            PID#:  BE2968
SETTING CLASSIFICATION:  Culvert Headwall


The bench mark is set into the top of the culvert headwall at the intersection
of old 9th Street and Feral Lane, 48.7 feet (14.8 m) south of the centerline of
old 9th Street (now a private drive), 18.2 feet (5.5 m) NE of the centerline of
Feral Lane, and 0.9 foot (0.3 m) NW of the SE end of the concrete headwall.

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

                                                   PUBLICATION DATE:  12/09/1987
Station ID: 8729071                                SUPERCEDED DATE:   04/21/2003
Name:       MILL BAYOU, NORTH BAY                             
            FLORIDA
NOAA Chart: 11390                                  Latitude:         30° 14.7' N
USGS Quad:  SPRINGFIELD                            Longitude:        85° 36.3' W


                            T I D A L   D A T U M S 


Tidal datums at MILL BAYOU, NORTH BAY based on:

     LENGTH OF SERIES:      1 MONTH
     TIME PERIOD:           NOVEMBER 1976
     TIDAL EPOCH:           1960-1978
     CONTROL TIDE STATION:  8729840 PENSACOLA


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

     HIGHEST OBSERVED WATER LEVEL (01/06/1977)         =   2.84
     MEAN HIGHER HIGH WATER                     MHHW   =   1.52
     MEAN HIGH WATER                            MHW    =   1.43
     MEAN TIDE LEVEL                            MTL    =   0.78
   * NATIONAL GEODETIC VERTICAL DATUM           NGVD29 =   0.26
     MEAN LOW WATER                             MLW    =   0.13
     MEAN LOWER LOW WATER                       MLLW   =   0.00
     LOWEST  OBSERVED WATER LEVEL (11/23/1976)         =  -1.34

   * NGVD is based on elevations published in Quad N360853, 6/73 and NOS
     leveling of 3/84. 
North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In FEET above:

     Stamping or Designation                    MLLW        MHW

     9071 A 1976                                14.30     12.87
     9071 B 1976                                 9.09      7.66
     9071 C 1976                                10.39      8.96
     9071 D 1976                                13.82     12.39
     9071 E 1984                                16.80     15.37


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

                                                   PUBLICATION DATE:  12/09/1987
Station ID: 8729071                                SUPERCEDED DATE:   04/21/2003
Name:       MILL BAYOU, NORTH BAY                             
            FLORIDA
NOAA Chart: 11390                                  Latitude:         30° 14.7' N
USGS Quad:  SPRINGFIELD                            Longitude:        85° 36.3' 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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