U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 8724238 PUBLICATION DATE: 03/09/2004
Name: MUNSON KEY
FL
NOAA Chart: 11445 Latitude: 24° 37.4' N ( 24.62330)
USGS Quad: LOGGERHEAD KEY Longitude: 81° 24.2' W ( -81.40330)
To reach the tidal bench marks from the east end of the U.S. Highway 1 bridge
between Little Torch Key and Big Pine Key, proceed SW by boat 5.8 km (3.1 nm) to
the west end of Munson Island, Newfound Harbor Keys. The bench marks are
located on the grounds of the Newfound Harbor Yacht Club. The tide gage and
staff were located at the inside bend of the pier at the yacht club.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: NO 1 1937
DESIGNATION: 872 4238 TIDAL 1
MONUMENTATION: Tidal Station disk VM#: 6847
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Concrete block OPUS PID:
LATITUDE: 24° 37.4' N ( 24.62330) LONGITUDE: 81° 24.2' W ( -81.40330)
The primary bench mark is a disk set flush in the SW corner of a concrete block
located on the grounds of the Newfound Harbor Yacht Club on Munson Key near the
pier, 47.24 m (155.0 ft) SW of bench mark 4238 F 1984, 9.75 m (32.0 ft) SE of
the SE corner of the pier, 6.49 m (21.3 ft) NNE of the northwest side of the
house, 2.99 m (9.8 ft) NW of the NW side of the house.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 8724238 PUBLICATION DATE: 03/09/2004
Name: MUNSON KEY
FL
NOAA Chart: 11445 Latitude: 24° 37.4' N ( 24.62330)
USGS Quad: LOGGERHEAD KEY Longitude: 81° 24.2' W ( -81.40330)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 2 1937
DESIGNATION: 872 4238 TIDAL 2
MONUMENTATION: Tidal Station disk VM#: 6848
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Concrete step OPUS PID:
LATITUDE: 24° 37.4' N ( 24.62330) LONGITUDE: 81° 24.2' W ( -81.40330)
The bench mark is a disk set flush in the second concrete step of the NE steps
to the storm house (NE of the main building), and 15.21 m (49.9 ft) south of
bench mark 4238 F 1984.
BENCH MARK STAMPING: NO 5 1973
DESIGNATION: 872 4238 TIDAL 5
MONUMENTATION: Tidal Station disk VM#: 6849
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete step OPUS PID:
LATITUDE: 24° 37.4' N ( 24.62330) LONGITUDE: 81° 24.2' W ( -81.40330)
The bench mark is a disk set flush in the bottom concrete step located at the NW
side of the storm house, 6.25 m (20.5 ft) east of the NE corner of the main
house, 5.64 m (18.5 ft) SW of the north corner of the storm house, and 2.83 m
(9.3 ft) NE of the west corner of the storm house.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 8724238 PUBLICATION DATE: 03/09/2004
Name: MUNSON KEY
FL
NOAA Chart: 11445 Latitude: 24° 37.4' N ( 24.62330)
USGS Quad: LOGGERHEAD KEY Longitude: 81° 24.2' W ( -81.40330)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 6 1973
DESIGNATION: 872 4238 TIDAL 6
MONUMENTATION: Tidal Station disk VM#: 6850
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete foundation OPUS PID:
LATITUDE: 24° 37.4' N ( 24.62330) LONGITUDE: 81° 24.2' W ( -81.40330)
The bench mark is a disk set flush in the concrete foundation located inside the
doorway of the generator building, 13 m (42 ft) ENE of bench mark NO 2 1937,
0.73 m (2.4 ft) NE of the SW side of the generator building, and 0.18 m (0.6 ft)
SE of the NW side of the generator building.
BENCH MARK STAMPING: 4238 F 1984
DESIGNATION: 872 4238 TIDAL F
MONUMENTATION: Tidal Station disk VM#: 6851
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 24° 37.4' N ( 24.62330) LONGITUDE: 81° 24.2' W ( -81.40330)
The bench mark is a disk set flush in a 0.30 m (1.0 ft) diameter concrete
monument with a 4-inch PVC pipe imbedded in the center, 18 m (59 ft) NNE of
bench mark NO 5 1973, 13.93 m (45.7 ft) NW of the west corner of the generator
building, 1.52 m (5.0 ft) west of the south corner of an outhouse, and 1.43 m
(4.7 ft) SW of the west corner of an outhouse.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 8724238 PUBLICATION DATE: 03/09/2004
Name: MUNSON KEY
FL
NOAA Chart: 11445 Latitude: 24° 37.4' N ( 24.62330)
USGS Quad: LOGGERHEAD KEY Longitude: 81° 24.2' W ( -81.40330)
T I D A L D A T U M S
Tidal datums at MUNSON KEY based on:
LENGTH OF SERIES: 2 MONTHS
TIME PERIOD: November 1973 - December 1973
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8724580 KEY WEST
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 0.528
MEAN HIGH WATER MHW = 0.452
MEAN SEA LEVEL MSL = 0.252
MEAN TIDE LEVEL MTL = 0.250
MEAN LOW WATER MLW = 0.047
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 1937 2.090 1.638
NO 2 1937 2.179 1.727
NO 5 1973 2.029 1.577
NO 6 1973 1.497 1.045
4238 F 1984 1.505 1.053
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 8724238 PUBLICATION DATE: 03/09/2004
Name: MUNSON KEY
FL
NOAA Chart: 11445 Latitude: 24° 37.4' N ( 24.62330)
USGS Quad: LOGGERHEAD KEY Longitude: 81° 24.2' W ( -81.40330)
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.