Superseded Bench Mark Sheet for 8729974, PERDIDO KEY, OLD RIVER FL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:  06/21/1984
Station ID: 8729974                                SUPERCEDED DATE:   04/21/2003
Name:       PERDIDO KEY, OLD RIVER                            
            FLORIDA
NOAA Chart: 11382                                  Latitude:         30° 18.2' N
USGS Quad:  PERDIDO BAY                            Longitude:        87° 26.7' W


To reach the tidal bench marks from the south end of the SR292 bridge over Old
River, proceed SW on Gulf Beach Highway 2.3 miles (3.7 km) to a black top road
leading NW, then on the black top road continue 0.4 miles (0.6 km) to a private
residence on the north side of the road.  The bench marks are located along the
blacktop road, and the tide gage and staff were located on a dock behind a
private residence (Kaufman).


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


                 PRIMARY BENCH MARK STAMPING:  9974 A 1977

MONUMENTATION:           Survey Disk                               VM#:    10332
AGENCY:                                                            PID#:  BG3646
SETTING CLASSIFICATION:  Copper-Coated Steel Rod


The bench mark is in front of the Kaufman residence, 67.5 feet (20.6 m) east of
Bench Mark 9974 E 1977, 28.2 feet (8.6 m) NW of the centerline of a blacktop
road, and 7.0 feet (2.1 m) NE of a power pole.  The bench mark is 0.2 foot (0.1
m) below ground level, crimped to a copper-coated steel rod driven to refusal
and encased in a 4-inch PVC pipe and concrete kickblock.



                         BENCH MARK STAMPING:  9974 B 1977

MONUMENTATION:           Survey Disk                               VM#:    10333
AGENCY:                                                            PID#:  BG3644
SETTING CLASSIFICATION:  Copper-Coated Steel Rod


The bench mark is 385 feet (117 m) SW of Bench Mark 9974 A 1977, 62 feet (19 m)
SW of the center of a drainage ditch, 25 feet (8 m) NE of a power pole, 23 feet
(7 m) NW of the centerline of the blacktop road.  The bench mark is 0.5 foot
(0.2 m) below ground level, crimped to a copper-coated steel rod driven 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:  06/21/1984
Station ID: 8729974                                SUPERCEDED DATE:   04/21/2003
Name:       PERDIDO KEY, OLD RIVER                            
            FLORIDA
NOAA Chart: 11382                                  Latitude:         30° 18.2' N
USGS Quad:  PERDIDO BAY                            Longitude:        87° 26.7' W


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


                         BENCH MARK STAMPING:  9974 C 1977

MONUMENTATION:           Survey Disk                               VM#:    10334
AGENCY:                                                            PID#:  BG3643
SETTING CLASSIFICATION:  Copper-Coated Steel Rod


The bench mark is 300 feet (91 m) SW of Bench Mark 9974 B 1977, 86.5 feet (26.3
m) NE of the NE corner of house #1018, and 18.4 feet (5.6 m) NW of the
centerline of a blacktop road.  The bench mark is 0.3 foot (0.1 m) below ground
level, crimped to a copper-coated steel rod driven to refusal and encased in a
PVC pipe and concrete kickblock.



                         BENCH MARK STAMPING:  9974 D 1977

MONUMENTATION:           Survey Disk                               VM#:    10335
AGENCY:                                                            PID#:  BG3642
SETTING CLASSIFICATION:  Copper-Coated Steel Rod


The bench mark is 330 feet (101 m) SW of Bench Mark 9974 C 1977, 161.5 feet
(49.2 m) SE of the SE corner of house#1019, 59 feet (18 m) SE of power pole
0913, and 26 feet (8 m) SE of the centerline of the blacktop road.  The bench
mark is 0.1 foot (0.03 m) below ground level, crimped to a copper-coated steel
rod driven to refusal and encased in a PVC pipe and concrete kickblock.



                         BENCH MARK STAMPING:  9974 E 1977

MONUMENTATION:           Survey Disk                               VM#:    10336
AGENCY:                                                            PID#:  BG3645
SETTING CLASSIFICATION:  Concrete Foundation


The bench mark is set flush in the NW corner of a concrete pump slab, 75.4 feet
(23.0 m) SE of the NE corner of house #1017, 67.5 feet (20.6 m) west of Bench
Mark 9974 A 1977 and 33 feet (10 m) NE of the centerline of the driveway for
house #1017.

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

                                                   PUBLICATION DATE:  06/21/1984
Station ID: 8729974                                SUPERCEDED DATE:   04/21/2003
Name:       PERDIDO KEY, OLD RIVER                            
            FLORIDA
NOAA Chart: 11382                                  Latitude:         30° 18.2' N
USGS Quad:  PERDIDO BAY                            Longitude:        87° 26.7' W


                            T I D A L   D A T U M S 


Tidal datums at PERDIDO KEY, OLD RIVER based on:

     LENGTH OF SERIES:      2 MONTHS
     TIME PERIOD:           MARCH-APRIL 1977
     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 (03/28/1977)         =   1.75
     MEAN HIGHER HIGH WATER                     MHHW   =   0.64
     MEAN HIGH WATER                            MHW    =   0.60
     MEAN TIDE LEVEL                            MTL    =   0.30
     MEAN LOW WATER                             MLW    =   0.01
     MEAN LOWER LOW WATER                       MLLW   =   0.00
     LOWEST  OBSERVED WATER LEVEL (01/20/1977)         =  -1.30

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In FEET above:

     Stamping or Designation                    MLLW        MHW

     9974 A 1977                                 3.76      3.16
     9974 B 1977                                 2.82      2.22
     9974 C 1977                                 5.40      4.80
     9974 D 1977                                 3.77      3.17
     9974 E 1977                                 4.98      4.38


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

                                                   PUBLICATION DATE:  06/21/1984
Station ID: 8729974                                SUPERCEDED DATE:   04/21/2003
Name:       PERDIDO KEY, OLD RIVER                            
            FLORIDA
NOAA Chart: 11382                                  Latitude:         30° 18.2' N
USGS Quad:  PERDIDO BAY                            Longitude:        87° 26.7' 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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