Superseded Bench Mark Sheet for 8729045, LAIRD BAYOU, EAST BAY FL

Present Epoch

Printable version

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  5

                                                   PUBLICATION DATE:  04/17/2000
Station ID: 8729045                                SUPERCEDED DATE:   04/21/2003
Name:       LAIRD BAYOU, EAST BAY                             
            FLORIDA
NOAA Chart: 11389                                  Latitude:         30°  7.3' N
USGS Quad:  LONG POINT                             Longitude:        85° 31.7' W


To reach the tidal bench marks from the intersection of State Highway 22 and
U.S. Highway 98 bypass, proceed east on State Highway 22 for 8.5 km (5.3 mi) to
State Highway S-167, then south on State Highway S-167 for 2.9 km (1.8 mi) to
the first dirt road after crossing Cooks Bayou, go east on the dirt road for 1.9
km (1.2 mi) to its end.  The bench marks are located across the Bayou on the
spit of land at Laird Point.  The tide gage and staff were located on a small
platform at the entrance to Laird Bayou, 17m (55 ft) east of the west shore.


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


                 PRIMARY BENCH MARK STAMPING:  NO 2 1935
                         DESIGNATION:          872 9045 NO 2

MONUMENTATION:           Tidal Station disk                        VM#:     9954
AGENCY:                  US Coast and Geodetic Survey (USC&GS)     PID:         
SETTING CLASSIFICATION:  Concrete monument


The primary bench mark is a disk set in top of a concrete monument on the west
shore of Laird Bayou and north of Laird Point, 57 m (188 ft) SSE of bench mark
9045 A 1976, 30 m (100 ft) north of the point on the west side of the bayou
entrance, 18 m (60 ft) inshore from the approximate high water line, 3 m (10 ft)
WSW of a pine tree, 0.3 m (1 ft) east of a witness post, and at ground level.



                         BENCH MARK STAMPING:  9045 A 1976
                         DESIGNATION:          872 9045 A

MONUMENTATION:           Tidal Station disk                        VM#:     9955
AGENCY:                  National Ocean Survey (NOS)               PID:         
SETTING CLASSIFICATION:  Copper-clad steel rod


The bench mark is a disk set on the west shore of Laird Bayou and north of Laird
Point, 89 m (292 ft) south of bench mark 9045 B 1976, 8.29 m (27.2 ft) SW of the
approximate high water line, 3 m (10 ft) east of a stand of bushes on high
ground, and 0.3 m (1 ft) east of a witness post.  The bench mark is 0.15 m (0.5
ft) below ground level, crimped to a copper-clad steel rod driven 12.2 m (40 ft)
to refusal, and encased in a 4-inch PVC pipe and concrete kickblock.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  5

                                                   PUBLICATION DATE:  04/17/2000
Station ID: 8729045                                SUPERCEDED DATE:   04/21/2003
Name:       LAIRD BAYOU, EAST BAY                             
            FLORIDA
NOAA Chart: 11389                                  Latitude:         30°  7.3' N
USGS Quad:  LONG POINT                             Longitude:        85° 31.7' W


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


                         BENCH MARK STAMPING:  9045 B 1976
                         DESIGNATION:          872 9045 B

MONUMENTATION:           Tidal Station disk                        VM#:     9956
AGENCY:                  National Ocean Survey (NOS)               PID:         
SETTING CLASSIFICATION:  Copper-clad steel rod


The bench mark is a disk set 152 m (498 ft) NNW of bench mark NO 2 1935, 5.49 m
(18.0 ft) west of the approximate high water line, 2.13 m (7.0 ft) south of a
small tidal creek, and 0.3 m (1 ft) east of a witness post.  The bench mark is
0.12 m (0.4 ft) below ground level, crimped to a copper-clad steel rod driven
12.2 m (40 ft) to refusal, and encased in a 4-inch PVC pipe and concrete
kickblock.



                         BENCH MARK STAMPING:  9045 C 1976
                         DESIGNATION:          872 9045 C

MONUMENTATION:           Tidal Station disk                        VM#:     9957
AGENCY:                  National Ocean Survey (NOS)               PID:         
SETTING CLASSIFICATION:  Copper-clad steel rod


The bench mark is a disk set 82 m (270 ft) north of bench mark 9045 B 1976, 22 m
(72 ft) west of the approximate high water line, and 2.50 m (8.2 ft) south of a
0.3 m (1 ft) diameter tree with witness sign.  The bench mark is 0.24 m (0.8 ft)
below ground level, crimped to a copper-clad steel rod driven 12.2 m (40 ft) to
refusal, and encased in a 4-inch PVC pipe and concrete kickblock.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  5

                                                   PUBLICATION DATE:  04/17/2000
Station ID: 8729045                                SUPERCEDED DATE:   04/21/2003
Name:       LAIRD BAYOU, EAST BAY                             
            FLORIDA
NOAA Chart: 11389                                  Latitude:         30°  7.3' N
USGS Quad:  LONG POINT                             Longitude:        85° 31.7' W


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


                         BENCH MARK STAMPING:  9045 D 1991
                         DESIGNATION:          872 9045 D

MONUMENTATION:           Flange-encased Rod                        VM#:    12498
AGENCY:                  National Ocean Service (NOS)              PID:         
SETTING CLASSIFICATION:  Stainless steel rod


The bench mark is a metal rod set at the northeasternmost point of land
approximately 400 m (1300 ft)  ENE of Laird Point, 5.58 m (18.3 ft) NNE of a
0.06 m (0.2 ft) diameter cedar tree, 5.21 m (17.1 ft) north of a 0.18 m (0.6 ft)
diameter oak tree (easternmost of a group of three oak trees), 5.09 m (16.7 ft)
SW of a 0.18 m (0.6 ft) diameter oak tree, 4.42 m (14.5 ft) WNW of the west edge
of the approximate high water line of Laird Bayou, 3.4 m (11.0 ft) ESE of the
east edge of a needle grass marsh area, and 0.43 m (1.4 ft) ESE of a Carsonite
witness post.  The datum point is the top of a stainless steel rod driven 13.1 m
(43 ft) to refusal and encased in a 5-inch PVC pipe with logo cap.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  5

                                                   PUBLICATION DATE:  04/17/2000
Station ID: 8729045                                SUPERCEDED DATE:   04/21/2003
Name:       LAIRD BAYOU, EAST BAY                             
            FLORIDA
NOAA Chart: 11389                                  Latitude:         30°  7.3' N
USGS Quad:  LONG POINT                             Longitude:        85° 31.7' W


                            T I D A L   D A T U M S 


Tidal datums at LAIRD BAYOU, EAST BAY based on:

     LENGTH OF SERIES:      1 MONTHS
     TIME PERIOD:           September 1991 - September 1991
     TIDAL EPOCH:           1960-1978
     CONTROL TIDE STATION:  8729108 PANAMA CITY, ST. ANDREW BAY


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

     MEAN HIGHER HIGH WATER                     MHHW   =  0.456
     MEAN HIGH WATER                            MHW    =  0.423
     MEAN TIDE LEVEL                            MTL    =  0.229
     MEAN SEA LEVEL                             MSL    =  0.223
     MEAN LOW WATER                             MLW    =  0.035
     MEAN LOWER LOW WATER                       MLLW   =  0.000



Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     NO 2 1935                                   0.915    0.492
     9045 A 1976                                 0.654    0.231
     9045 B 1976                                 0.390   -0.033
     9045 C 1976                                 0.497    0.074
     9045 D 1991                                 1.000    0.577


                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  5 of  5

                                                   PUBLICATION DATE:  04/17/2000
Station ID: 8729045                                SUPERCEDED DATE:   04/21/2003
Name:       LAIRD BAYOU, EAST BAY                             
            FLORIDA
NOAA Chart: 11389                                  Latitude:         30°  7.3' N
USGS Quad:  LONG POINT                             Longitude:        85° 31.7' 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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