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Datums Page Page 1 of 5
Station ID: 8729381 PUBLICATION DATE: 05/20/2004
Name: BASIN CREEK
FL
NOAA Chart: 11385 Latitude: 30° 29.8' N ( 30.49670)
USGS Quad: FREEPORT Longitude: 86° 14.4' W ( -86.24000)
To reach the tidal bench marks from the junction of U.S. Highway 331 and State
Highway 20 in Freeport, proceed west on State Highway 20 for 9.3 km (5.8 mi) to
a sand road leading NW, then NW along the sand road for 2.01 km (1.25 mi) to the
boat ramp at the Basin Bayou State Recreational Area, operated by the Florida
Department of Natural Resources. The bench marks are along the sand road. The
tide gage and staff were located on a free standing structure located 10.67 m
(35.0 ft) SW of the boat ramp.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 9381 C 1977
DESIGNATION: 872 9381 C TIDAL
MONUMENTATION: Tidal Station disk VM#: 10108
AGENCY: National Ocean Survey (NOS) IDB PID#: BG4600
SETTING CLASSIFICATION: Galvanized steel rod OPUS PID:
LATITUDE: 30° 29.8' N ( 30.49670) LONGITUDE: 86° 14.3' W ( -86.23830)
The primary bench mark is a disk located 53.89 m (176.8 ft) SSW of bench mark
9381 D 1977, 74 m (242 ft) SE of bench mark 9381 B 1977, 30 m (100 ft) ESE of
the centerline of the sand road, 7 m (23 ft) NE of the centerline of a trail
road leading SE, and 0.24 m (0.8 ft) SW of a witness post. The bench mark is
set 3 cm (0.1 ft) below ground level, crimped to the top of a galvanized steel
rod driven 12.2 m (40 ft), 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 5
Station ID: 8729381 PUBLICATION DATE: 05/20/2004
Name: BASIN CREEK
FL
NOAA Chart: 11385 Latitude: 30° 29.8' N ( 30.49670)
USGS Quad: FREEPORT Longitude: 86° 14.4' W ( -86.24000)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 9381 A 1977
DESIGNATION: 872 9381 A TIDAL
MONUMENTATION: Tidal Station disk VM#: 10106
AGENCY: National Ocean Survey (NOS) IDB PID#: BG4602
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 30° 29.8' N ( 30.49670) LONGITUDE: 86° 14.4' W ( -86.24000)
The bench mark is a disk set in the top of a concrete monument, 1.98 m (6.5 ft)
NW of the centerline of the drive to the boat ramp, 19.05 m (62.5 ft) NE of the
shoreline at the boat ramp, 11 m (36 ft) NW of a 0.61 m (2.0 ft) diameter pine
tree, 16 m (53 ft) of a 0.76 m (2.5 ft) diameter oak tree, 0.61 m (2.0 ft) SE of
a witness post, and at ground level.
BENCH MARK STAMPING: 9381 B 1977
DESIGNATION: 872 9381 B TIDAL
MONUMENTATION: Tidal Station disk VM#: 10107
AGENCY: National Ocean Survey (NOS) IDB PID#: BG4601
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 30° 29.8' N ( 30.49670) LONGITUDE: 86° 14.4' W ( -86.24000)
The bench mark is a disk set in the top of a concrete monument, 54 m (177 ft)
SSE of bench mark 9381 A 1977, 74 m (242 ft) NW of bench mark 9381 C 1977, 12 m
(40 ft) NE of the shoreline, 3.63 m (11.9 ft) SW of the centerline of the sand
road, 0.46 m (1.5 ft) NE of a witness post, and at ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 8729381 PUBLICATION DATE: 05/20/2004
Name: BASIN CREEK
FL
NOAA Chart: 11385 Latitude: 30° 29.8' N ( 30.49670)
USGS Quad: FREEPORT Longitude: 86° 14.4' W ( -86.24000)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 9381 D 1977
DESIGNATION: 872 9381 D TIDAL
MONUMENTATION: Tidal Station disk VM#: 10109
AGENCY: National Ocean Survey (NOS) IDB PID#: BG4599
SETTING CLASSIFICATION: Galvanized steel rod OPUS PID:
LATITUDE: 30° 29.8' N ( 30.49670) LONGITUDE: 86° 14.3' W ( -86.23830)
The bench mark is a disk located 62 m (205 ft) WNW of bench mark 9381 E 1977,
53.92 m (176.9 ft) NNE of bench mark 9381 C 1977, 3.41 m (11.2 ft) NW of the
centerline of the sand road, 3 m (10 ft) SE of a multi-trunked oak tree, and
0.24 m (0.8 ft) SE of a witness post. The bench mark is crimped to the top of a
galvanized steel rod driven 12.2 m (40 ft), and encased in a PVC pipe and
concrete kickblock.
BENCH MARK STAMPING: 9381 E 1977
DESIGNATION: 872 9381 E TIDAL
MONUMENTATION: Tidal Station disk VM#: 10110
AGENCY: National Ocean Survey (NOS) IDB PID#: BG4598
SETTING CLASSIFICATION: Galvanized steel rod OPUS PID:
LATITUDE: 30° 29.8' N ( 30.49670) LONGITUDE: 86° 14.3' W ( -86.23830)
The bench mark is a disk located 62 m (205 ft) NE of bench mark 9381 D 1977,
3.60 m (11.8 ft) SE of the centerline of the sand road, and 0.18 m (0.6 ft) NW
of a witness post. The bench mark is set 3 cm (0.1 ft) below ground level,
crimped to the top of a galvanized steel rod driven 12.2 m (40 ft), and encased
in a PVC pipe and concrete kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 8729381 PUBLICATION DATE: 05/20/2004
Name: BASIN CREEK
FL
NOAA Chart: 11385 Latitude: 30° 29.8' N ( 30.49670)
USGS Quad: FREEPORT Longitude: 86° 14.4' W ( -86.24000)
T I D A L D A T U M S
Tidal datums at BASIN CREEK based on:
LENGTH OF SERIES: 5 MONTHS
TIME PERIOD: July 1977 - November 1977
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8729840 PENSACOLA, PENSACOLA BAY
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 0.150
MEAN HIGH WATER MHW = 0.141
MEAN SEA LEVEL MSL = 0.075
MEAN TIDE LEVEL MTL = 0.072
MEAN LOW WATER MLW = 0.003
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum NAVD88 = -0.024
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
9381 C 1977 2.593 2.452
9381 A 1977 1.252 1.111
9381 B 1977 1.762 1.621
9381 D 1977 3.909 3.768
9381 E 1977 4.297 4.156
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 8729381 PUBLICATION DATE: 05/20/2004
Name: BASIN CREEK
FL
NOAA Chart: 11385 Latitude: 30° 29.8' N ( 30.49670)
USGS Quad: FREEPORT Longitude: 86° 14.4' W ( -86.24000)
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.
Station Location
Published bench mark
Unpublished bench mark
