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Datums Page Page 1 of 6
Station ID: 8723970 PUBLICATION DATE: 09/26/2011
Name: VACA KEY, FLORIDA BAY
FL
NOAA Chart: 11449 Latitude: 24° 42.7' N ( 24.71170)
USGS Quad: MARATHON Longitude: 81° 6.3' W ( -81.10500)
To reach the tidal bench marks from the Post Office in Marathon, go WSW on U.S.
Highway 1 for 2.9 km (1.8 mi) to the U.S. Coast Guard Station Marathon. The
bench marks are in the area of the Coast Guard Station, Faro Blanco Resort, and
nearby Buccaneer Resort. The tide gage and staff are on a platform at the NW
corner of the Coast Guard boat basin.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 3970 N 1999
DESIGNATION: 872 3970 N
MONUMENTATION: Tidal Station disk VM#: 15849
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Bulkhead with deep piles OPUS PID:
LATITUDE: 24° 42.6' N ( 24.71069) LONGITUDE: 81° 6.4' W ( -81.10642)
The primary bench mark is a disk set flush in the concrete bulkhead in the SW
area of the U.S. Coast Guard Station, 32.00 m (104.99 ft) NE of the SW corner of
the USCG rental units 3 and 4, 17.45 m (57.25 ft) SE of the SE face of the round
waste treatment tank, 0.35 m (1.15 ft) west of the SE face of the bulkhead, and
0.30 m (0.98 ft) east of the west edge of the bulkhead.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 6
Station ID: 8723970 PUBLICATION DATE: 09/26/2011
Name: VACA KEY, FLORIDA BAY
FL
NOAA Chart: 11449 Latitude: 24° 42.7' N ( 24.71170)
USGS Quad: MARATHON Longitude: 81° 6.3' W ( -81.10500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 3970 A 1978
DESIGNATION: 872 3970 A TIDAL
MONUMENTATION: Tidal Station disk VM#: 698
AGENCY: National Ocean Survey (NOS) IDB PID#: AA0895
SETTING CLASSIFICATION: Walkway OPUS PID:
LATITUDE: 24° 42.5' N ( 24.70914) LONGITUDE: 81° 6.3' W ( -81.10481)
The bench mark is a disk set flush in the walkway around the Faro Blanco Resort
Check-In Office, 56.39 m (185.01 ft) east of bench mark 3970 B 1978, 40.75 m
(133.69 ft) north of the centerline of U.S. Highway 1, 5.79 m (19.0 ft) west of
the centerline of the driveway, and 0.52 m (1.71 ft) NE of the NE corner of the
Office. NOTE: this mark is under the building overhang and needs a short rod
for leveling.
BENCH MARK STAMPING: 3970 B 1978
DESIGNATION: 872 3970 B TIDAL
MONUMENTATION: Tidal Station disk VM#: 699
AGENCY: National Ocean Survey (NOS) IDB PID#: AA0894
SETTING CLASSIFICATION: Walkway OPUS PID:
LATITUDE: 24° 42.6' N ( 24.70917) LONGITUDE: 81° 6.2' W ( -81.10408)
The bench mark is a disk set flush in the walkway around Pancho's (closed),
56.39 m (185.01 ft) west of bench mark 3970 A 1978, 35.24 m (115.62 ft) north of
the centerline of U.S. Highway 1, 3.23 m (10.60 ft) SSW of the SW corner of the
walkway, and 0.3 m (1.0 ft) SW of the SW corner of the grill. Note: Restuarant
is Panchos and is closed.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 6
Station ID: 8723970 PUBLICATION DATE: 09/26/2011
Name: VACA KEY, FLORIDA BAY
FL
NOAA Chart: 11449 Latitude: 24° 42.7' N ( 24.71170)
USGS Quad: MARATHON Longitude: 81° 6.3' W ( -81.10500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 3970 K 1988
DESIGNATION: 872 3970 K TIDAL
MONUMENTATION: Tidal Station disk VM#: 702
AGENCY: Florida Dept. of Natural Resources IDB PID#: AA1708
SETTING CLASSIFICATION: Concrete flagpole base OPUS PID:
LATITUDE: 24° 42.6' N ( 24.70944) LONGITUDE: 81° 6.4' W ( -81.10597)
The bench mark is a tidal disk set in the SE corner of the black concrete base
of the flagpole at the U.S. Coast Guard Station Marathon, 32.95 m (108.10 ft) SW
of bench mark 3970 L 1988, 21.18 m (69.49 ft) ESE of the NE corner of the main
building, and 9.97 m (32.71 ft) west of the centerline of the Coast Guard
Station road.
BENCH MARK STAMPING: 3970 L 1988
DESIGNATION: 872 3970 L TIDAL
MONUMENTATION: Tidal Station disk VM#: 703
AGENCY: Florida Dept. Natural Resource IDB PID#: AA1707
SETTING CLASSIFICATION: Rock Outcrop OPUS PID#: AA1707
LATITUDE: 24° 42.6' N ( 24.70972) LONGITUDE: 81° 6.4' W ( -81.10586)
The bench mark is a disk set flush in a rock outcrop at the Coast Guard Station,
32.95 m (108.10 ft) NE of flagpole with black base, 18.41 m (60.4 ft) NNW of the
SW corner of the tennis court, 11.83 m (38.81 ft) SSW of the NW corner of the
tennis court, and 4.42 m (14.50 ft) east of the centerline of the coast guard
station road, and at ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 6
Station ID: 8723970 PUBLICATION DATE: 09/26/2011
Name: VACA KEY, FLORIDA BAY
FL
NOAA Chart: 11449 Latitude: 24° 42.7' N ( 24.71170)
USGS Quad: MARATHON Longitude: 81° 6.3' W ( -81.10500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 3970 M 1988
DESIGNATION: 872 3970 M TIDAL
MONUMENTATION: Tidal Station disk VM#: 704
AGENCY: National Ocean Service (NOS) IDB PID#: AA1706
SETTING CLASSIFICATION: Rock Outcrop OPUS PID:
LATITUDE: 24° 42.6' N ( 24.70961) LONGITUDE: 81° 6.3' W ( -81.10567)
The bench mark is a disk set flush under the grass in a rock outcrop at the
Coast Guard Station, 24.29 m (79.69 ft) north of the SE corner of the tennis
court, 23.47 m ( 77.00 ft) ENE of bench mark 3970 L 1988, 5.58 m (18.31ft) SSE
of the NE corner of the tennis court, and 3.41 m (11.19 ft) west of a chain link
fence along the east property line.
BENCH MARK STAMPING: 3970 P 2010
DESIGNATION: 872 3970 P
MONUMENTATION: Bench Mark disk VM#: 19618
AGENCY: IDB PID#:
SETTING CLASSIFICATION: Sea Wall USCG Base OPUS PID:
LATITUDE: 24° 42.6' N ( 24.71039) LONGITUDE: 81° 6.4' W ( -81.10631)
The bench mark is a disk located in Vaca Key on the east sea wall of the USCG
marina, approximately 30.193 m (99.1 ft) NW of the NW corner of the USCG
maintenence building, 19.403 m (63.7 ft) east of the west side sea wall of the
USCG marina, 4.285 m (14.1 ft) west of the NW corner of the residental house
located on the USCG property, 3.045 m (10.0 ft) NE of the north side of the
light pole on the east sea wall, 0.265 m (0.9 ft) east of the waters edge.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 6
Station ID: 8723970 PUBLICATION DATE: 09/26/2011
Name: VACA KEY, FLORIDA BAY
FL
NOAA Chart: 11449 Latitude: 24° 42.7' N ( 24.71170)
USGS Quad: MARATHON Longitude: 81° 6.3' W ( -81.10500)
T I D A L D A T U M S
Tidal datums at VACA KEY, FLORIDA BAY based on:
LENGTH OF SERIES: 19 YEARS
TIME PERIOD: January 1983 - December 2001
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 (10/24/2005) = 2.064
North American Vertical Datum NAVD88 = 0.407
MEAN HIGHER HIGH WATER MHHW = 0.297
MEAN HIGH WATER MHW = 0.265
MEAN SEA LEVEL MSL = 0.156
MEAN TIDE LEVEL MTL = 0.156
MEAN LOW WATER MLW = 0.047
MEAN LOWER LOW WATER MLLW = 0.000
LOWEST OBSERVED WATER LEVEL (02/04/1971) = -0.321
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
3970 N 1999 0.949 0.684
3970 A 1978 1.628 1.363
3970 B 1978 1.522 1.257
3970 K 1988 1.221 0.956
3970 L 1988 1.473 1.208
3970 M 1988 1.510 1.245
3970 P 2010 0.931 0.666
Foot Notes:
Bench marks 3970 P 2010 is 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 this mark.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 6
Station ID: 8723970 PUBLICATION DATE: 09/26/2011
Name: VACA KEY, FLORIDA BAY
FL
NOAA Chart: 11449 Latitude: 24° 42.7' N ( 24.71170)
USGS Quad: MARATHON Longitude: 81° 6.3' W ( -81.10500)
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
