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

                                                                                
Station ID: 8729376                         PUBLICATION DATE:  12/20/2023
Name:       SANTA ROSA HOGTOWN BAYOU                          
            FL
NOAA Chart: 11385                           Latitude:   30° 24.0' N (  30.40000)
USGS Quad:  FREEPORT                        Longitude:  86° 13.7' W ( -86.22830)


To reach the tidal bench marks from the intersection of U.S. Highway 98 and
County Road 393 in Santa Rosa Beach, proceed north on County Road 393 for 2.6 km
(1.6 mi) to the Charles E. Cessna Landing on the south shore of Hogtown Bayou. 
The bench marks are in the vicinity of Lions Park and along County Road 393. 
Turn left and go northwest on the paved entrance road for about 260 Ft. (79.2m)
to a dock on the right and the Aquatrak.


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


                 PRIMARY BENCH MARK STAMPING:  9376 A 1977
                         DESIGNATION:          872 9376 A TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:        10101
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Concrete chimmey foundation           OPUS PID#: BG3580
LATITUDE:   30° 23.9' N (  30.39850)          LONGITUDE:  86° 13.8' W ( -86.22922)


The bench mark is a disk set in the top of an old chimney foundation, 87 m (285
ft) west of the centerline of County Road 393, 16.00 m (52.5 ft) SE of the SE
corner of the westernmost covered picnic table in Lions Park, 2 m (5 ft) north
of a light pole, and 1.07 m (3.5 ft) above ground level.



                         BENCH MARK STAMPING:  9376 C 1992
                         DESIGNATION:          872 9376 C

MONUMENTATION:           Tidal Station disk                    VM#:        16528
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Concrete racquet ball court           OPUS PID#: DQ5789
LATITUDE:   30° 23.9' N (  30.39814)          LONGITUDE:  86° 13.8' W ( -86.22992)


The bench mark is a disk located 79.2 m (260.0 ft) SW of (NOS mark 9367 A 1977,
7.3 m (24.0 ft) SW of a carsonite witness post, and 0.5 m (1.5 ft) SE of a
cement block wall.

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

                                                                                
Station ID: 8729376                         PUBLICATION DATE:  12/20/2023
Name:       SANTA ROSA HOGTOWN BAYOU                          
            FL
NOAA Chart: 11385                           Latitude:   30° 24.0' N (  30.40000)
USGS Quad:  FREEPORT                        Longitude:  86° 13.7' W ( -86.22830)


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


                         BENCH MARK STAMPING:  9376 H 2016
                         DESIGNATION:          872 9736 H

MONUMENTATION:           Flange-encased Rod                    VM#:        24357
AGENCY:                  National Geodetic Survey (NGS)        IDB PID#:        
SETTING CLASSIFICATION:  Stainless Steel Rod                   OPUS PID#: DQ5790
LATITUDE:   30° 23.9' N (  30.39783)          LONGITUDE:  86° 13.8' W ( -86.22994)


The bench mark is a flange encased rod located 34.5 m (113.2 ft) east of a
carsonite witness post, 21.9 m (71.8 ft) south of the SW corner of a racquetball
court, 14.0 m (45.8 ft) NNE of concrete light pole number 114504, 6.8 m (22.3
ft) north of the approximate centerline of Hogtown Bayou Lane, and 3.9 m (12.8
ft) NW of the SE end of a concrete sidewalk.  The datum point is the top of a
stainless steel rod driven 14.2 m (46.6 ft) to refusal, and encased in 12 cm
(0.4 ft) PVC with a NOS logo cap.



                         BENCH MARK STAMPING:  9376 G 2016
                         DESIGNATION:          872 9376 G

MONUMENTATION:           Flange-encased Rod                    VM#:        24358
AGENCY:                  National Geodetic Survey (NGS)        IDB PID#:        
SETTING CLASSIFICATION:  Stainless Steel Rod                   OPUS PID#: DQ5788
LATITUDE:   30° 23.9' N (  30.39842)          LONGITUDE:  86° 13.8' W ( -86.22953)


The bench mark is a stainless steel rod located 30.9 m (101.4 ft) west of NOS
mark 9367 A 1977, 13.7 m (45.0 ft) WNW of the approximate centerline of Hogtown
Bayou Lane, 413.1 m (43.0) SSE of a carsonite witness post, 12.6 m (41.3 ft) SE
of the SE corner of a wooden fishing pier, and 3.9 m (12.8 ft) WNW of the NW
edge of a gravel parking lot. The datum point is the top of a stainless steel
rod driven 13.3m (43.7 ft) to refusal and encased in NOS logo cap.

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

                                                                                
Station ID: 8729376                         PUBLICATION DATE:  12/20/2023
Name:       SANTA ROSA HOGTOWN BAYOU                          
            FL
NOAA Chart: 11385                           Latitude:   30° 24.0' N (  30.40000)
USGS Quad:  FREEPORT                        Longitude:  86° 13.7' W ( -86.22830)


                            T I D A L   D A T U M S 


Tidal datums at SANTA ROSA HOGTOWN BAYOU based on:

     LENGTH OF SERIES:      4 MONTHS
     TIME PERIOD:           April 2021 - July 2021
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  8729840 PENSACOLA, PENSACOLA BAY


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

     North American Vertical Datum              NAVD88 =  0.370
     MEAN HIGHER HIGH WATER                     MHHW   =  0.183
     MEAN HIGH WATER                            MHW    =  0.177
     MEAN SEA LEVEL                             MSL    =  0.090
     MEAN TIDE LEVEL                            MTL    =  0.088
     MEAN LOWER LOW WATER                       MLLW   =  0.000
     MEAN LOW WATER                             MLW    =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     9376 A 1977                                 2.118    1.941
     9376 C 1992                                 1.173    0.996
     9376 H 2016                                 1.364    1.187
     9376 G 2016                                 1.001    0.824


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

                                                                                
Station ID: 8729376                         PUBLICATION DATE:  12/20/2023
Name:       SANTA ROSA HOGTOWN BAYOU                          
            FL
NOAA Chart: 11385                           Latitude:   30° 24.0' N (  30.40000)
USGS Quad:  FREEPORT                        Longitude:  86° 13.7' W ( -86.22830)


                             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 NGS's Integrated Data Base (IDB PID)
provides geodetic datum based on traditionally leveled and bluebooked ties to
the National Spatial Reference System(NSRS) https://www.ngs.noaa.gov/datasheets/.
The NGS Online Positioning User Service (OPUS PID) provides geodetic datum based
on GPS position & tie it to the NSRS https://www.ngs.noaa.gov/OPUS/.

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.