U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 8724033 PUBLICATION DATE: 12/12/2003
Name: PIGEON KEY (INSIDE)
FL
NOAA Chart: 11449 Latitude: 24° 42.3' N ( 24.70500)
USGS Quad: SEVENMILE BRIDGE Longitude: 81° 9.4' W ( -81.15670)
To reach the tidal bench marks from the post office in Marathon, proceed 4.7 km
(2.9 mi) SW along U.S. Highway 1 to the old Seven Mile Bridge, go 3.1 km (1.9
mi) on the old bridge to the ramp leading down from Seven Mile Bridge to Pigeon
Key. The bench marks are located on the concrete bases of the old bridge piers
and near the pool on the south end of the Key. The tide gage and staff were
located on the dock at the north end of the Key. This bench mark network was
also used for tide station 872 4032 which was located on the south end of the
Key.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: NO 1 1935
DESIGNATION: 872 4033 TIDAL 1
MONUMENTATION: Tidal Station disk VM#: 6315
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: AA0292
SETTING CLASSIFICATION: Concrete base for bridge pier OPUS PID:
LATITUDE: 24° 42.3' N ( 24.70500) LONGITUDE: 81° 9.3' W ( -81.15500)
The primary bench mark is a disk set in the top of the north corner of the
concrete base to the third pier NE of the bridge pier at the edge of the water
on the west side of the Key, 10 m (32 ft) west of the extended centerline of the
dock on the north side of the Key, 3 m (9 ft) SW of the center of a sideway,
0.15 m (0.5 ft) north of the north corner of the bridge pier, and 0.46 m (1.5
ft) above ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 8724033 PUBLICATION DATE: 12/12/2003
Name: PIGEON KEY (INSIDE)
FL
NOAA Chart: 11449 Latitude: 24° 42.3' N ( 24.70500)
USGS Quad: SEVENMILE BRIDGE Longitude: 81° 9.4' W ( -81.15670)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 3 1935
DESIGNATION: 872 4033 TIDAL 3
MONUMENTATION: Tidal Station disk VM#: 6316
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: AA0291
SETTING CLASSIFICATION: Concrete base for bridge pier OPUS PID:
LATITUDE: 24° 42.3' N ( 24.70500) LONGITUDE: 81° 9.4' W ( -81.15670)
The bench mark is a disk set in the top of the north corner of the concrete base
of the bridge pier located at the edge of the water on the west side of the Key
under the old Savannah Bridge, 2 m (6 ft) NE of the extended centerline of the
ramp leading to the Key, and 1 m (2 ft) above ground level.
BENCH MARK STAMPING: MOSER 1935 NO 4 1976
DESIGNATION: MOSER RM 4
MONUMENTATION: Reference Mark disk VM#: 6317
AGENCY: National Geodetic Survey (NGS) IDB PID#: AA0924
SETTING CLASSIFICATION: Concrete floor OPUS PID:
LATITUDE: 24° 42.3' N ( 24.70500) LONGITUDE: 81° 9.3' W ( -81.15500)
The bench mark is a disk set in the top of the SE corner of the concrete floor
of the picnic area located on Pigeon Key near the shark pool, 24.29 m (79.7 ft)
north of bench mark 90 70 C17, 21 m (69 ft) SSE of the corner of a fence at the
entrance to Pigeon Key, and 0.03 m (0.1 ft) above ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 8724033 PUBLICATION DATE: 12/12/2003
Name: PIGEON KEY (INSIDE)
FL
NOAA Chart: 11449 Latitude: 24° 42.3' N ( 24.70500)
USGS Quad: SEVENMILE BRIDGE Longitude: 81° 9.4' W ( -81.15670)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: V 278 1966
DESIGNATION: V 278
MONUMENTATION: Bench Mark disk VM#: 6318
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: AA0289
SETTING CLASSIFICATION: Concrete curb OPUS PID:
LATITUDE: 24° 42.3' N ( 24.70500) LONGITUDE: 81° 9.3' W ( -81.15500)
The bench mark is a disk set in the top of the north curb located at the old
Seven Mile Bridge near the junction of U.S. Highway 1 and the road leading down
the ramp to Pigeon Key, 3 m (10 ft) north of the centerline of the highway, and
0.15 m (0.5 ft) above highway level.
BENCH MARK STAMPING: 90 70 C17
DESIGNATION: C17
ALIAS: DOT
MONUMENTATION: Survey disk VM#: 6319
AGENCY: Florida Department of Transportation
(FLDT) IDB PID#: AA0923
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 24° 42.2' N ( 24.70330) LONGITUDE: 81° 9.3' W ( -81.15500)
The bench mark is a disk set in a concrete monument located on the SW side of an
old swimming pool/boat dock, 112 m (369 ft) south of the bridge abutment, 26.03
m (85.4 ft) SW of the NW end of the shark pool, 24.20 m (79.4 ft) south of the
west side of a concrete pavillion, 5.61 m (18.4 ft) NW of the SW end of the
pool, 2.83 m (9.3 ft) west of the west end of the pool, 0.55 m (1.8 ft) east of
a witness post, and 0.06 m (0.2 ft) above ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 8724033 PUBLICATION DATE: 12/12/2003
Name: PIGEON KEY (INSIDE)
FL
NOAA Chart: 11449 Latitude: 24° 42.3' N ( 24.70500)
USGS Quad: SEVENMILE BRIDGE Longitude: 81° 9.4' W ( -81.15670)
T I D A L D A T U M S
Tidal datums at PIGEON KEY (INSIDE) based on:
LENGTH OF SERIES: 2 MONTHS
TIME PERIOD: November 1973 - December 1973
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8724211 BIG PINE KEY VIADUCT
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
North American Vertical Datum NAVD88 = 0.394
MEAN HIGHER HIGH WATER MHHW = 0.298
MEAN HIGH WATER MHW = 0.219
MEAN SEA LEVEL MSL = 0.143
MEAN TIDE LEVEL MTL = 0.130
MEAN LOW WATER MLW = 0.041
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 1935 1.165 0.946
NO 3 1935 1.156 0.937
MOSER 1935 NO 4 1976 0.796 0.577
V 278 1966 8.396 8.177
90 70 C17 0.868 0.649
Foot Notes:
Bench marks 90 70 C17 and MOSER 1935 NO 4 1976 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 5 of 5
Station ID: 8724033 PUBLICATION DATE: 12/12/2003
Name: PIGEON KEY (INSIDE)
FL
NOAA Chart: 11449 Latitude: 24° 42.3' N ( 24.70500)
USGS Quad: SEVENMILE BRIDGE Longitude: 81° 9.4' W ( -81.15670)
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.