U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 8729364 PUBLICATION DATE: 04/29/2004
Name: ALLAQUAY BAYOU
FL
NOAA Chart: 11388 Latitude: 30° 29.3' N ( 30.48830)
USGS Quad: FREEPORT Longitude: 86° 12.3' W ( -86.20500)
To reach the tidal bench marks from the junction of U.S. Highway 331 (North) and
State Highway 20 in Freeport, proceed west on State Highway 20 for 6.9 km (4.3
mi) to Whitfield Road, proceed south on Whitfield Road for 2.16 km (1.35 mi) to
its end at a private fish camp. The bench marks are along the drive (extension
of Whitfield Road) to the fish camp. The tide gage and staff were located on a
private dock at the fish camp.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 9364 A 1977
DESIGNATION: 872 9364 A TIDAL
MONUMENTATION: Tidal Station disk VM#: 10096
AGENCY: National Ocean Survey (NOS) IDB PID#: BG4608
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 30° 29.4' N ( 30.49000) LONGITUDE: 86° 12.4' W ( -86.20670)
The bench mark is a disk set in the top of a concrete monument, 79 m (715 ft)
south of bench mark 9364 B 1977, 30.33 m (99.5 ft) ENE of the NE corner of the
main cabin, 21 m (70 ft) north of the shoreline, and 7.19 m (23.6 ft) NW of the
NW corner of the pumphouse.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 8729364 PUBLICATION DATE: 04/29/2004
Name: ALLAQUAY BAYOU
FL
NOAA Chart: 11388 Latitude: 30° 29.3' N ( 30.48830)
USGS Quad: FREEPORT Longitude: 86° 12.3' W ( -86.20500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 9364 B 1977
DESIGNATION: 872 9364 B TIDAL
MONUMENTATION: Tidal Station disk VM#: 10097
AGENCY: National Ocean Survey (NOS) IDB PID#: BG4607
SETTING CLASSIFICATION: Galvanized steel rod OPUS PID:
LATITUDE: 30° 29.4' N ( 30.49000) LONGITUDE: 86° 12.3' W ( -86.20500)
The bench mark is a disk located 103 m (338 ft) SSE of bench mark 9364 C 1977,
17.68 m (58.0 ft) NNW of the NW corner of the northeasternmost cottage, 4.15 m
(13.6 ft) east of the centerline of the drive, and 0.40 m (1.3 ft) west of a
witness post. The bench mark is set 6 cm (0.2 ft) below ground level, crimped
to the top of a galvanized steel rod driven 12.2 m (40 ft) to refusal, encased
in a PVC pipe and a concrete kickblock.
BENCH MARK STAMPING: 9364 C 1977
DESIGNATION: 872 9364 C TIDAL
MONUMENTATION: Tidal Station disk VM#: 10098
AGENCY: National Ocean Survey (NOS) IDB PID#: BG4606
SETTING CLASSIFICATION: Galvanized steel rod OPUS PID:
LATITUDE: 30° 29.5' N ( 30.49170) LONGITUDE: 86° 12.3' W ( -86.20500)
The bench mark is a disk located 82 m (269 ft) SSE of bench mark 9364 D 1977 and
4.72 m (15.5 ft) ENE of the centerline of the drive, 10.36 m (34.0 ft) SSW of a
0.6 m (2 ft) diameter oak tree, 64.47 m (211.5 ft) SSE of the northernmost
powerline pole on the property, and 0.40 m (1.3 ft) WSW of a witness post. The
bench mark is set 6 cm (0.2 ft) above ground level, crimped to the top of a
galvanized steel rod driven 12.2 m (40 ft) to refusal, encased in a PVC pipe and
a concrete kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 8729364 PUBLICATION DATE: 04/29/2004
Name: ALLAQUAY BAYOU
FL
NOAA Chart: 11388 Latitude: 30° 29.3' N ( 30.48830)
USGS Quad: FREEPORT Longitude: 86° 12.3' W ( -86.20500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 9364 D 1977
DESIGNATION: 872 9364 D TIDAL
MONUMENTATION: Tidal Station disk VM#: 10099
AGENCY: National Ocean Survey (NOS) IDB PID#: BG4605
SETTING CLASSIFICATION: Galvanized steel rod OPUS PID:
LATITUDE: 30° 29.5' N ( 30.49170) LONGITUDE: 86° 12.4' W ( -86.20670)
The bench mark is a disk located 74.68 m (245.0 ft) SW of bench mark 9364 E
1977, 31 m (101 ft) NE of the northernmost powerline pole on the property, 50 m
(165 ft) SW of the SE end of a corrugated pipe under the drive, 5.33 m (17.5 ft)
WNW of the centerline of the drive, and 0.49 m (1.6 ft) ESE of a witness post.
The bench mark is set at ground level, crimped to the top of a galvanized steel
rod driven 11.0 m (36 ft) to refusal, encased in a PVC pipe and a concrete
kickblock.
BENCH MARK STAMPING: 9364 E 1977
DESIGNATION: 872 9364 E TIDAL
MONUMENTATION: Tidal Station disk VM#: 10100
AGENCY: National Ocean Survey (NOS) IDB PID#: BG4604
SETTING CLASSIFICATION: Galvanized steel rod OPUS PID:
LATITUDE: 30° 29.5' N ( 30.49170) LONGITUDE: 86° 12.3' W ( -86.20500)
The bench mark is a disk located 283 m (930 ft) north of the shoreline, 23.41 m
(76.8 ft) NE of the SE end of a corrugated pipe culvert under the drive at a
90-degree curve in the drive, 3 m (10 ft) south of the east-west fence line,
3.20 m (10.5 ft) north of the centerline of Whitfield Road, and 0.37 m (1.2 ft)
south of a witness post. The bench mark is set at ground level, crimped to the
top of a galvanized steel rod driven to refusal, encased in PVC pipe and
concrete kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 8729364 PUBLICATION DATE: 04/29/2004
Name: ALLAQUAY BAYOU
FL
NOAA Chart: 11388 Latitude: 30° 29.3' N ( 30.48830)
USGS Quad: FREEPORT Longitude: 86° 12.3' W ( -86.20500)
T I D A L D A T U M S
Tidal datums at ALLAQUAY BAYOU 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 = 0.153
MEAN HIGH WATER MHW = 0.146
MEAN TIDE LEVEL MTL = 0.075
MEAN SEA LEVEL MSL = 0.073
MEAN LOW WATER MLW = 0.003
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum NAVD88 = -0.032
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
9364 A 1977 0.838 0.692
9364 B 1977 0.654 0.508
9364 C 1977 0.735 0.589
9364 D 1977 0.589 0.443
9364 E 1977 0.729 0.583
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 8729364 PUBLICATION DATE: 04/29/2004
Name: ALLAQUAY BAYOU
FL
NOAA Chart: 11388 Latitude: 30° 29.3' N ( 30.48830)
USGS Quad: FREEPORT Longitude: 86° 12.3' W ( -86.20500)
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.