U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 6
Station ID: 8728229 PUBLICATION DATE: 04/18/2024
Name: SHELL POINT, WALKER CREEK
FL
NOAA Chart: 11405 Latitude: 30° 3.5' N ( 30.05833)
USGS Quad: SPRING CREEK Longitude: 84° 17.4' W ( -84.29056)
THE GAUGE IS ABOUT 9.6 MI (15.4 KM) SOUTH-SOUTHEAST OF CRAWFORDVILLE, 8.7 MI
(14.0 KM) SOUTHWEST OF SAINT MARKS, 2.7 MI (4.3 KM) SOUTHEAST OF SPRING CREEK,
IN LOT 121 OF THE HARTSFIELD SURVEY. TO REACH THE GAUGE FROM THE INTERSECTION OF
U.S. HIGHWAY 98 (COASTAL HIGHWAY) AND COUNTY ROAD 365 (SPRING CREEK HIGHWAY) 5.1
MI (8.2 KM) SOUTHEAST OF CRAWFORDVILLE, GO SOUTH ON COUNTY ROAD 365 (SPRING
CREEK HIGHWAY) FOR 1.3 MI (2.1 KM) TO THE JUNCTION OF COUNTY ROAD 367 (SHELL
POINT ROAD) ON THE LEFT, TURN LEFT ON COUNTY ROAD 367 (SHELL POINT ROAD) AND GO
SOUTHERLY FOR 1.5 MI (2.4 KM) TO THE JUNCTION OF COUNTY ROAD 367A, CONTINUE
SOUTHEASTERLY ON COUNTY ROAD 367 (SHELL POINT ROAD) FOR 3.0 MI (4.8 KM) TO THE
JUNCTION OF BEATY TAFF DRIVE, TURN LEFT ON BEATY TAFF DRIVE AND GO EAST FOR 0.2
MI (0.3 KM) TO THE JUNCTION OF PEBBLE COURT ON THE LEFT AND THE GAUGE ON THE
LEFT, ATTACHED TO THE SOUTHEAST HEADWALL. BENCHMARKS ARE LOCATED IN THE VICINITY
ALONG SHELL POINT ROAD AND BEATY TAFF DRIVE.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 8229 G 2016
DESIGNATION: 872 8229 G
MONUMENTATION: Flange-encased Rod VM#: 24571
AGENCY: National Geodetic Survey (NGS) IDB PID#:
SETTING CLASSIFICATION: Stainles steel rod OPUS PID#: DR3122
LATITUDE: 30° 3.5' N ( 30.05811) LONGITUDE: 84° 17.4' W ( -84.28994)
The bench mark is a stainless steel rod located 44.3 m (145.2 ft) ENE of the NE
corner of the restroom facility, 15.1 m (49.5 ft) NNE of the approximate
centerline of Beatty Taft Drive, 10.7 m (35.0 ft) west of the approximate
centerline of Pebble Court, 4.1 m (13.6 ft) NNE of a carsonite witness post, and
0.7 m (2.2 ft) east of the east end of a concrete barrier of shell point beach
parking lot. The datum point is the top of a stainless steel rod driven 5.7m
(18.9 ft) to refusal, and encased in a 13.0 cm (5.0 in) PVC with a NGS logo cap.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 6
Station ID: 8728229 PUBLICATION DATE: 04/18/2024
Name: SHELL POINT, WALKER CREEK
FL
NOAA Chart: 11405 Latitude: 30° 3.5' N ( 30.05833)
USGS Quad: SPRING CREEK Longitude: 84° 17.4' W ( -84.29056)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: SHELL POINT II 1933
DESIGNATION: SHELL POINT 2
MONUMENTATION: Triangulation Station disk VM#: 8296
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Concrete monument OPUS PID#: BE1938
LATITUDE: 30° 3.5' N ( 30.05772) LONGITUDE: 84° 17.3' W ( -84.28903)
The bench mark is a disk set flush in a concrete monument 33.5 m (110 ft) north
of the shoreline of Apalachee Bay, 17.68 m (58.0 ft) south from the approximate
centerline of the Marina Road, 11.28 m (37.0 ft) WSW from a 0.8 m (2.6 ft)
diameter cedar tree, 0.46 m (1.5 ft) NE from a carsonite witness post set in
concrete, and 0.24 m (0.8 ft) north from a metal witness post.
BENCH MARK STAMPING: 8229 F 2016
DESIGNATION: 872 8229 F
MONUMENTATION: Survey disk VM#: 24572
AGENCY: FLDEP IDB PID#:
SETTING CLASSIFICATION: concrete monument OPUS PID:
LATITUDE: 30° 3.6' N ( 30.05917) LONGITUDE: 84° 17.6' W ( -84.29344)
The bench mark is a disk located 17.6 m (57.7 ft) north of the approximate
centerline of Beatty Taft Drive, 12.2 m (39.9 ft) south of the exit lane of
Shell Point boat ramp, 9.8 m (32.0 ft) east of the approximate centerline of
County Road 367 (Shell Point Road), 3.7 m (12.3 ft) west of a chain link fence,
and 3.7 m (12.2 ft) west of a carsonite witness post.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 6
Station ID: 8728229 PUBLICATION DATE: 04/18/2024
Name: SHELL POINT, WALKER CREEK
FL
NOAA Chart: 11405 Latitude: 30° 3.5' N ( 30.05833)
USGS Quad: SPRING CREEK Longitude: 84° 17.4' W ( -84.29056)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 8229 H 2017
DESIGNATION: 872 8229 H
MONUMENTATION: Flange-encased Rod VM#: 24573
AGENCY: National Geodetic Survey (NGS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 30° 3.7' N ( 30.06086) LONGITUDE: 84° 17.6' W ( -84.29364)
The bench mark is a stainless steel rod located 27.3 m (89.7 ft) south of the
approximate centerline of Walker Creek Drive, 10.0 m (32.9 ft) SE of wooden
power pole number A3 173 l 1 with a transformer attached, 6.8 m (22.3 ft) east
of the approximate centerline of Shell Point Road, 4.2 m (13.9 ft) NNW of the NE
corner of a concrete storm drain, and 3.4 m (11.3 ft) west of a carsonite
witness post. The datum point is the top of a stainless steel rod driven 10.4 m
(34.2 ft) to refusal and encased in a 13.0 cm (5.0 in) PVC with a NGS logo cap.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 6
Station ID: 8728229 PUBLICATION DATE: 04/18/2024
Name: SHELL POINT, WALKER CREEK
FL
NOAA Chart: 11405 Latitude: 30° 3.5' N ( 30.05833)
USGS Quad: SPRING CREEK Longitude: 84° 17.4' W ( -84.29056)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: P 394 1981
DESIGNATION: P 394
MONUMENTATION: Flange-encased Rod VM#: 24574
AGENCY: National Geodetic Survey (NGS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 30° 4.2' N ( 30.06947) LONGITUDE: 84° 17.8' W ( -84.29633)
The bench mark is a stainless steel rod located 13.7 m (45.0 ft) SE of a 72-inch
wooden sign post, 8.8 m (28.9 ft) WSW of the centerline of County Road 367, 0.7
m (2.3 ft) SW of a metal witness post, and 0.5 m (1.8 ft) ENE of a carsonite
witness post. The datum point is the top of a stainless steel rod driven 12.8 m
(42.0 ft) to refusal and encased in a 13.0 cm (5.0 in) PVC with a NGS logo cap.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 6
Station ID: 8728229 PUBLICATION DATE: 04/18/2024
Name: SHELL POINT, WALKER CREEK
FL
NOAA Chart: 11405 Latitude: 30° 3.5' N ( 30.05833)
USGS Quad: SPRING CREEK Longitude: 84° 17.4' W ( -84.29056)
T I D A L D A T U M S
Tidal datums at SHELL POINT, WALKER CREEK based on:
LENGTH OF SERIES: 1 YEAR
TIME PERIOD: July 2022 - June 2023
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8727520 CEDAR KEY, GULF OF MEXICO
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
HIGHEST OBSERVED WATER LEVEL (08/30/2023) = 2.333
MEAN HIGHER HIGH WATER MHHW = 1.075
MEAN HIGH WATER MHW = 1.006
North American Vertical Datum NAVD88 = 0.615
MEAN TIDE LEVEL MTL = 0.607
MEAN SEA LEVEL MSL = 0.602
MEAN LOW WATER MLW = 0.207
MEAN LOWER LOW WATER MLLW = 0.000
LOWEST OBSERVED WATER LEVEL (09/29/2022) = -0.956
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
8229 G 2016 2.184 1.178
SHELL POINT II 1933 2.709 1.703
8229 F 2016 1.740 0.734
8229 H 2017 2.201 1.195
P 394 1981 1.895 0.889
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 6
Station ID: 8728229 PUBLICATION DATE: 04/18/2024
Name: SHELL POINT, WALKER CREEK
FL
NOAA Chart: 11405 Latitude: 30° 3.5' N ( 30.05833)
USGS Quad: SPRING CREEK Longitude: 84° 17.4' W ( -84.29056)
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.