U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 8724979 PUBLICATION DATE: 02/26/2004
Name: BIG MARCO RIVER, U.S. 92
FL
NOAA Chart: 11429 Latitude: 25° 56.0' N ( 25.93330)
USGS Quad: MARCO ISLAND Longitude: 81° 39.3' W ( -81.65500)
To reach the tidal bench marks from the intersection of U.S. Highway 41 and
State Road 92, proceed west on State Road 92 for 10.3 km (6.4 mi), going over
Big Marco River, to Moran's Barge Marina. The bench marks are located in the
area around Moran's Barge Marina and to the east. The tide gage and staff were
located on the Moran's Barge Marina Pier.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 4979 A 1978
DESIGNATION: 872 4979 A TIDAL
MONUMENTATION: Tidal Station disk VM#: 9753
AGENCY: National Ocean Survey (NOS) IDB PID#: AC3392
SETTING CLASSIFICATION: Concrete sea wall OPUS PID:
LATITUDE: 25° 56.0' N ( 25.93330) LONGITUDE: 81° 39.3' W ( -81.65500)
The primary bench mark is a disk set in the concrete sea wall on the east side
of the Moran's Barge Marina boat ramp, 8.53 m (28.0 ft) SE of the NE corner of
Moran's Barge Marina.
BENCH MARK STAMPING: 4979 B 1978
DESIGNATION: 872 4979 B TIDAL
MONUMENTATION: Tidal Station disk VM#: 9754
AGENCY: National Ocean Survey (NOS) IDB PID#: AC3393
SETTING CLASSIFICATION: Concrete sea wall OPUS PID:
LATITUDE: 25° 56.0' N ( 25.93330) LONGITUDE: 81° 39.3' W ( -81.65500)
The bench mark is a disk set flush in the concrete sea wall on the west side of
the Moran's Barge Marina boat ramp, and 5.15 m (16.9 ft) SSE of the NE corner of
the tackle shop. NOTE: Mark not found in 2002 by US Power Squadron.
11/23/2002: Concrete walkways appear to have been placed on the sea wall since
last report.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 8724979 PUBLICATION DATE: 02/26/2004
Name: BIG MARCO RIVER, U.S. 92
FL
NOAA Chart: 11429 Latitude: 25° 56.0' N ( 25.93330)
USGS Quad: MARCO ISLAND Longitude: 81° 39.3' W ( -81.65500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 4979 C 1978
DESIGNATION: 872 4979 C TIDAL
MONUMENTATION: Tidal Station disk VM#: 9755
AGENCY: National Ocean Survey (NOS) IDB PID#: AC3395
SETTING CLASSIFICATION: Galvanized steel rod OPUS PID:
LATITUDE: 25° 55.9' N ( 25.93170) LONGITUDE: 81° 39.3' W ( -81.65500)
The bench mark is a disk located under the west end of the State Road 92 bridge
over Big Marco River, 61 m (200 ft) west of bench mark 4979 F 1978, 8 m (26 ft)
east of the centerline of a paved road (under the bridge) that leads to Moran's
Barge Marina, 0.30 m (1.0 ft) south of the south piling of the westernmost group
of pilings supporting the bridge, and 0.30 m (1.0 ft) south of a witness post.
The bench mark is crimped to a galvanized steel rod driven 7.3 m (24 ft) to
refusal, and encased in a 4-inch PVC pipe and concrete kickblock.
BENCH MARK STAMPING: 4979 E 1978
DESIGNATION: 872 4979 E TIDAL
MONUMENTATION: Tidal Station disk VM#: 9756
AGENCY: National Ocean Survey (NOS) IDB PID#: AC3396
SETTING CLASSIFICATION: Galvanized steel rod OPUS PID:
LATITUDE: 25° 55.9' N ( 25.93170) LONGITUDE: 81° 39.3' W ( -81.65500)
The bench mark is a disk located 61 m (200 ft) south of the State Road 92 bridge
over Big Marco River, 27 m (87 ft) SE of the junction of the drive to the
Moran's Barge Marina and County Road 892 (Goodland Road), 12 m (39 ft) south of
a concrete power pole, 1 m (3 ft) east of a small monument to old Goodland Road,
and 0.46 m (1.5 ft) east of a witness post. The bench mark is 0.09 m (0.3 ft)
below the gravel around monument, crimped to a galvanized steel rod driven 6.7 m
(22 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
Station ID: 8724979 PUBLICATION DATE: 02/26/2004
Name: BIG MARCO RIVER, U.S. 92
FL
NOAA Chart: 11429 Latitude: 25° 56.0' N ( 25.93330)
USGS Quad: MARCO ISLAND Longitude: 81° 39.3' W ( -81.65500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 4979 F 1978
DESIGNATION: 872 4979 F TIDAL
MONUMENTATION: Tidal Station disk VM#: 9757
AGENCY: National Ocean Survey (NOS) IDB PID#: AC3394
SETTING CLASSIFICATION: Bridge pier foundation OPUS PID:
LATITUDE: 25° 55.9' N ( 25.93170) LONGITUDE: 81° 39.3' W ( -81.65500)
The bench mark is a disk under the State Road 92 bridge over Big Marco River,
set in the SW corner of the base of the westernmost concrete bridge pier that is
in the water, 17.83 m (58.5 ft) north of the north side of the old wooden bridge
and 1 m (2 ft) above the approximate high water mark.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 8724979 PUBLICATION DATE: 02/26/2004
Name: BIG MARCO RIVER, U.S. 92
FL
NOAA Chart: 11429 Latitude: 25° 56.0' N ( 25.93330)
USGS Quad: MARCO ISLAND Longitude: 81° 39.3' W ( -81.65500)
T I D A L D A T U M S
Tidal datums at BIG MARCO RIVER, U.S. 92 based on:
LENGTH OF SERIES: 5 MONTHS
TIME PERIOD: March 1978 - July 1978
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8724967 MARCO ISLAND, CAXAMBAS PASS
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 1.021
MEAN HIGH WATER MHW = 0.943
North American Vertical Datum NAVD88 = 0.740
MEAN TIDE LEVEL MTL = 0.554
MEAN SEA LEVEL MSL = 0.551
MEAN LOW WATER MLW = 0.165
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
4979 A 1978 1.478 0.535
4979 B 1978 1.564 0.621
4979 C 1978 2.363 1.420
4979 E 1978 1.638 0.695
4979 F 1978 1.566 0.623
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 8724979 PUBLICATION DATE: 02/26/2004
Name: BIG MARCO RIVER, U.S. 92
FL
NOAA Chart: 11429 Latitude: 25° 56.0' N ( 25.93330)
USGS Quad: MARCO ISLAND Longitude: 81° 39.3' W ( -81.65500)
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.