U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 6
Station ID: 8724211 PUBLICATION DATE: 06/09/2003
Name: BIG PINE KEY VIADUCT
FL
NOAA Chart: 11445 Latitude: 24° 40.2' N ( 24.67000)
USGS Quad: BIG PINE KEY Longitude: 81° 22.1' W ( -81.36830)
To reach the tidal bench marks from the post office in Marathon, proceed 31.9 km
(19.8 mi) SW on U.S. Highway 1 to a gravel road on the right, then 0.1 km (0.05
mi) north along the gravel road to the first canal. The bench marks are located
in the vicinity of the canal and near the gravel road. The tide gage and staff
were located at the east end of the first canal, north of U.S. Highway 1.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: NO 1 1971
DESIGNATION: 872 4211 TIDAL 1
MONUMENTATION: Tidal Station disk VM#: 8912
AGENCY: National Ocean Survey (NOS) IDB PID#: AA0792
SETTING CLASSIFICATION: Concrete walkway OPUS PID:
LATITUDE: 24° 40.2' N ( 24.67000) LONGITUDE: 81° 22.1' W ( -81.36830)
The primary bench mark is a disk set in a concrete walkway around the canal,
located at the east end of the first canal north of U.S. Highway 1, 73.61 m
(241.5 ft) north of the centerline of U.S. Highway 1, 37 m (123 ft) west of the
centerline of the gravel road, 23.56 m (77.3 ft) west of bench mark J 328 1970,
2 m (7 ft) south of the south side of the canal, 0.12 m (0.4 ft) north of a low
cinder block wall, and 0.09 m (1.0 ft) below ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 6
Station ID: 8724211 PUBLICATION DATE: 06/09/2003
Name: BIG PINE KEY VIADUCT
FL
NOAA Chart: 11445 Latitude: 24° 40.2' N ( 24.67000)
USGS Quad: BIG PINE KEY Longitude: 81° 22.1' W ( -81.36830)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: J 328 1970
DESIGNATION: J 328
MONUMENTATION: Bench Mark disk VM#: 8913
AGENCY: National Geodetic Survey (NGS) IDB PID#: AA0235
SETTING CLASSIFICATION: Concrete sea wall OPUS PID:
LATITUDE: 24° 40.2' N ( 24.67000) LONGITUDE: 81° 22.1' W ( -81.36830)
The bench mark is a disk set in the top of the SE corner of a concrete seawall,
located at the east end of the first canal north of U.S. Highway 1, 73.61 m
(241.5 ft) north of the centerline of U.S. Highway 1, 20.39 m (66.9 ft) south of
bench mark K 328 1970, 14 m (46 ft) west of the centerline of the gravel road
leading north, 0.43 m (1.4 ft) NW of the SE corner of the sea wall and dock, and
1 m (2 ft) below the level of the ground.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 6
Station ID: 8724211 PUBLICATION DATE: 06/09/2003
Name: BIG PINE KEY VIADUCT
FL
NOAA Chart: 11445 Latitude: 24° 40.2' N ( 24.67000)
USGS Quad: BIG PINE KEY Longitude: 81° 22.1' W ( -81.36830)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: K 328 1970
DESIGNATION: K 328
MONUMENTATION: Bench Mark disk VM#: 8914
AGENCY: National Geodetic Survey (NGS) IDB PID#: AA0233
SETTING CLASSIFICATION: Concrete sea wall OPUS PID:
LATITUDE: 24° 40.2' N ( 24.67000) LONGITUDE: 81° 22.1' W ( -81.36830)
The bench mark is a disk set in top of the NE corner of a concrete sea wall,
located at the east end of the first canal north of U.S. Highway 1, 94.00 m
(308.4 ft) north of the centerline of U.S. Highway 1, 20.39 m (66.9 ft) north of
bench mark J 328 1970, 15 m (48 ft) west of the centerline of the gravel road,
and level with the top of the sea wall.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 6
Station ID: 8724211 PUBLICATION DATE: 06/09/2003
Name: BIG PINE KEY VIADUCT
FL
NOAA Chart: 11445 Latitude: 24° 40.2' N ( 24.67000)
USGS Quad: BIG PINE KEY Longitude: 81° 22.1' W ( -81.36830)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: M 328 1970
DESIGNATION: M 328
MONUMENTATION: Bench Mark disk VM#: 8915
AGENCY: National Geodetic Survey (NGS) IDB PID#: AA0226
SETTING CLASSIFICATION: Bedrock OPUS PID:
LATITUDE: 24° 40.3' N ( 24.67170) LONGITUDE: 81° 22.1' W ( -81.36830)
The bench mark is a disk set in the top of a mass of outcropping bedrock,
located 0.2 km (0.1 mi) north along the gravel road from U.S. Highway 1, 10 m
(32 ft) east of the centerline of the gravel road, 5 m (16 ft) NE of the 5#
powerline pole from U.S. Highway 1, and level with the ground.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 6
Station ID: 8724211 PUBLICATION DATE: 06/09/2003
Name: BIG PINE KEY VIADUCT
FL
NOAA Chart: 11445 Latitude: 24° 40.2' N ( 24.67000)
USGS Quad: BIG PINE KEY Longitude: 81° 22.1' W ( -81.36830)
T I D A L D A T U M S
Tidal datums at BIG PINE KEY VIADUCT based on:
LENGTH OF SERIES: 1 YEAR
TIME PERIOD: January 1974 - December 1974
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8724580 KEY WEST
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
HIGHEST OBSERVED WATER LEVEL (10/07/1974) = 0.679
North American Vertical Datum NAVD88 = 0.377
MEAN HIGHER HIGH WATER MHHW = 0.334
MEAN HIGH WATER MHW = 0.264
MEAN SEA LEVEL MSL = 0.148
MEAN TIDE LEVEL MTL = 0.143
MEAN LOW WATER MLW = 0.023
MEAN LOWER LOW WATER MLLW = 0.000
LOWEST OBSERVED WATER LEVEL (02/10/1971) = -0.373
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
NO 1 1971 0.880 0.616
J 328 1970 0.883 0.619
K 328 1970 1.367 1.103
M 328 1970 0.574 0.310
Foot Notes:
Bench mark M 328 1970 is based on one differential leveling connection and does
not meet the quality control standards of the NOS. Therefore, caution should be
used when deriving elevations for this mark.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 6
Station ID: 8724211 PUBLICATION DATE: 06/09/2003
Name: BIG PINE KEY VIADUCT
FL
NOAA Chart: 11445 Latitude: 24° 40.2' N ( 24.67000)
USGS Quad: BIG PINE KEY Longitude: 81° 22.1' W ( -81.36830)
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.