U.S. DEPARTMENT OF COMMERCE
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National Ocean Service
Datums Page Page 1 of 6
Station ID: 8724178 PUBLICATION DATE: 01/23/2004
Name: SPANISH HARBOR VIADUCT, BIG PINE KEY
FL
NOAA Chart: 11445 Latitude: 24° 38.9' N ( 24.64830)
USGS Quad: BIG PINE KEY Longitude: 81° 19.8' W ( -81.33000)
To reach the tidal bench marks from the post office in Marathon, proceed SW on
U.S. Highway 1 for 26.6 km (16.5 mi) to the west end of the bridge over Spanish
Harbor Channel. The bench marks are in the vicinity of the viaduct wing wall
and sea wall. The tide gage and staff were located on the north wing wall of
the west abutment of the Spanish Harbor Viaduct.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: NO 1 1936
DESIGNATION: 872 4178 TIDAL 1
MONUMENTATION: Tidal Station disk VM#: 6401
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: AA0258
SETTING CLASSIFICATION: Concrete wing wall OPUS PID:
LATITUDE: 24° 38.9' N ( 24.64830) LONGITUDE: 81° 19.8' W ( -81.33000)
The primary bench mark is a disk set in the top of the north concrete wing wall
at the west end of the Spanish Harbor Viaduct, 33 m (108 ft) north of the
centerline of U.S. Highway 1, and 5 m (15 ft) SE of the NW end of the winggwall.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 6
Station ID: 8724178 PUBLICATION DATE: 01/23/2004
Name: SPANISH HARBOR VIADUCT, BIG PINE KEY
FL
NOAA Chart: 11445 Latitude: 24° 38.9' N ( 24.64830)
USGS Quad: BIG PINE KEY Longitude: 81° 19.8' W ( -81.33000)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: F 70 RESET 1936
DESIGNATION: F 70 RESET
MONUMENTATION: Bench Mark disk VM#: 6402
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: AA0257
SETTING CLASSIFICATION: Concrete wing wall OPUS PID:
LATITUDE: 24° 38.9' N ( 24.64830) LONGITUDE: 81° 19.8' W ( -81.33000)
The bench mark is a disk set in the top of the north concrete wing wall at the
west end of Spanish Harbor Viaduct, 34 m (111 ft) SE of bench mark NO 1 1936, 4
m (14 ft) north of the centerline of U.S. Highway 1, and 1 m (3 ft) below U.S.
Highway 1.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 6
Station ID: 8724178 PUBLICATION DATE: 01/23/2004
Name: SPANISH HARBOR VIADUCT, BIG PINE KEY
FL
NOAA Chart: 11445 Latitude: 24° 38.9' N ( 24.64830)
USGS Quad: BIG PINE KEY Longitude: 81° 19.8' W ( -81.33000)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: K 273 1966
DESIGNATION: K 273
MONUMENTATION: Bench Mark disk VM#: 6403
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: AA0254
SETTING CLASSIFICATION: Concrete wing wall OPUS PID:
LATITUDE: 24° 38.9' N ( 24.64830) LONGITUDE: 81° 19.8' W ( -81.33000)
The bench mark is a disk set in the top of the south concrete wing wall at the
west end of Spanish Harbor Viaduct, 26 m (85 ft) south of the centerline of U.S.
Highway 1, 9.91 m (32.5 ft) NE of the SW end of the wing wall, and 3 m (10 ft)
below U.S. Highway 1.
BENCH MARK STAMPING: 4178 E 1982
DESIGNATION: 872 4178 E TIDAL
MONUMENTATION: Tidal Station disk VM#: 6404
AGENCY: National Ocean Survey (NOS) IDB PID#: AA0943
SETTING CLASSIFICATION: Concrete sea wall OPUS PID:
LATITUDE: 24° 38.9' N ( 24.64830) LONGITUDE: 81° 19.8' W ( -81.33000)
The bench mark is a disk set in the sea wall on the west end of the bridge over
Spanish Harbor Channel, on the south side of U.S. Highway 1, 58 m (190 ft) west
of the east end of the sea wall, 48.62 m (159.5 ft) east of the first power pole
west of the bridge, 0.3 m (1.0 ft) east of the west end of the sea wall, and 5 m
(15 ft) below U.S. Highway 1.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 6
Station ID: 8724178 PUBLICATION DATE: 01/23/2004
Name: SPANISH HARBOR VIADUCT, BIG PINE KEY
FL
NOAA Chart: 11445 Latitude: 24° 38.9' N ( 24.64830)
USGS Quad: BIG PINE KEY Longitude: 81° 19.8' W ( -81.33000)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 4178 F 1982
DESIGNATION: 872 4178 F TIDAL
MONUMENTATION: Tidal Station disk VM#: 6405
AGENCY: National Ocean Survey (NOS) IDB PID#: AA0944
SETTING CLASSIFICATION: Concrete sea wall OPUS PID:
LATITUDE: 24° 38.9' N ( 24.64830) LONGITUDE: 81° 19.8' W ( -81.33000)
The bench mark is a disk set in the sea wall on the west end of the bridge over
Spanish Harbor Channel, on the south side of U.S. Highway 1 where the sea wall
joins the bridge wing wall, and 5 m (15 ft) below U.S. Highway 1.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 6
Station ID: 8724178 PUBLICATION DATE: 01/23/2004
Name: SPANISH HARBOR VIADUCT, BIG PINE KEY
FL
NOAA Chart: 11445 Latitude: 24° 38.9' N ( 24.64830)
USGS Quad: BIG PINE KEY Longitude: 81° 19.8' W ( -81.33000)
T I D A L D A T U M S
Tidal datums at SPANISH HARBOR VIADUCT, BIG PINE KEY based on:
LENGTH OF SERIES: 1 MONTH
TIME PERIOD: June 1974 - June 1974
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8724580 KEY WEST
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
North American Vertical Datum NAVD88 = 0.442
MEAN HIGHER HIGH WATER MHHW = 0.426
MEAN HIGH WATER MHW = 0.349
MEAN SEA LEVEL MSL = 0.194
MEAN TIDE LEVEL MTL = 0.190
MEAN LOW WATER MLW = 0.031
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
NO 1 1936 0.690 0.341
F 70 RESET 1936 4.982 4.633
K 273 1966 0.672 0.323
4178 E 1982 1.564 1.215
4178 F 1982 1.556 1.207
Foot Notes:
Bench marks 4178 E 1982 and 4178 F 1982 are based on one differential leveling
connection and do not meet the quality control standards of the NOS. Therefore,
caution should be used when deriving elevations for these marks.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 6
Station ID: 8724178 PUBLICATION DATE: 01/23/2004
Name: SPANISH HARBOR VIADUCT, BIG PINE KEY
FL
NOAA Chart: 11445 Latitude: 24° 38.9' N ( 24.64830)
USGS Quad: BIG PINE KEY Longitude: 81° 19.8' W ( -81.33000)
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.