U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 4
PUBLICATION DATE: 07/15/1986
Station ID: 8724542 SUPERCEDED DATE: 04/21/2003
Name: SIGSBEE PARK, GARRISON BIGHT CHANNEL
FLORIDA
NOAA Chart: 11441 Latitude: 24° 35.1' N
USGS Quad: KEY WEST Longitude: 81° 46.5' W
To reach the tidal bench marks from the intersection of U.S. Highway 1 and
Sigsbee Road in Key West, proceed north on Sigsbee Road for 1.15 miles (1.85 km)
to Arthur Sawyer Road East, travel NW on Arthur Sawyer Road East for 0.05 mile
(0.08 km) to a road leading to the Navy Special Services Marina, then follow the
road to the marina. The bench marks are located within the marina compound.
The tide gage and staff were located on the SW shore of Sigsbee Park.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: NO 1 1974
MONUMENTATION: Survey Disk VM#: 10980
AGENCY: PID#: AA1007
SETTING CLASSIFICATION: Concrete Apron
The bench mark is set flush in a concrete apron on the SW corner of a boat
repair shop and sailboat house, 150 feet (46 m) NW of Bench Mark NO 3 1974, and
12 feet (4 m) SE of the NW shoreline of Sigsbee Park.
BENCH MARK STAMPING: NO 2 1974
MONUMENTATION: Survey Disk VM#: 10981
AGENCY: PID#: AA1008
SETTING CLASSIFICATION: Concrete Boat Ramp
The bench mark is set flush in the north corner of the boat ramp at the boat
repair shop and sailboat house, and 73 feet (22 m) NE of Bench Mark NO 1 1974.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 4
PUBLICATION DATE: 07/15/1986
Station ID: 8724542 SUPERCEDED DATE: 04/21/2003
Name: SIGSBEE PARK, GARRISON BIGHT CHANNEL
FLORIDA
NOAA Chart: 11441 Latitude: 24° 35.1' N
USGS Quad: KEY WEST Longitude: 81° 46.5' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 3 1974
MONUMENTATION: Survey Disk VM#: 10982
AGENCY: PID#: AA1009
SETTING CLASSIFICATION: Concrete Apron
The bench mark is set flush in a concrete apron for a small restroom building,
162 feet (49 m) SE of the NW shoreline, 24 feet (7 m) NW of the south corner of
the building.
BENCH MARK STAMPING: NO 4 1974
MONUMENTATION: Survey Disk VM#: 10983
AGENCY: PID#: AA1010
SETTING CLASSIFICATION: Concrete Seawall
The bench mark is set in the seawall for the fuel pier, 173.5 feet (52.9 m) east
of Bench Mark NO 3 1974, 82.5 feet (25.1 m) SE of the west edge of the fuel
pier, and 10 feet (3 m) SW of the north edge of the fuel pier.
BENCH MARK STAMPING: NO 5 1974
MONUMENTATION: Survey Disk VM#: 10984
AGENCY: PID#: AA1011
SETTING CLASSIFICATION: Concrete Seawall
The bench mark is set flush in the concrete seawall, at the NE corner of the
marina, 88.9 feet (27.1 m) east of Bench Mark NO 4 1974, 62.5 feet (19.0 m) NW
of the SE corner of the marina seawall, and 2.1 feet (0.6 m) SE of the north
corner of a curb in front of the marina office.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 4
PUBLICATION DATE: 07/15/1986
Station ID: 8724542 SUPERCEDED DATE: 04/21/2003
Name: SIGSBEE PARK, GARRISON BIGHT CHANNEL
FLORIDA
NOAA Chart: 11441 Latitude: 24° 35.1' N
USGS Quad: KEY WEST Longitude: 81° 46.5' W
T I D A L D A T U M S
Tidal datums at SIGSBEE PARK, GARRISON BIGHT CHANNEL based on:
LENGTH OF SERIES: 1 MONTH
TIME PERIOD: SEPTEMBER 1974
TIDAL EPOCH: 1960-1978
CONTROL TIDE STATION: 8724580 KEY WEST
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET:
HIGHEST OBSERVED WATER LEVEL (10/07/1974) = 2.80
MEAN HIGHER HIGH WATER MHHW = 1.52
MEAN HIGH WATER MHW = 1.25
MEAN TIDE LEVEL MTL = 0.73
MEAN LOW WATER MLW = 0.21
MEAN LOWER LOW WATER MLLW = 0.00
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In FEET above:
Stamping or Designation MLLW MHW
NO 1 1974 6.34 5.09
NO 2 1974 4.51 3.26
NO 3 1974 7.46 6.21
NO 4 1974 5.19 3.94
NO 5 1974 4.68 3.43
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 4
PUBLICATION DATE: 07/15/1986
Station ID: 8724542 SUPERCEDED DATE: 04/21/2003
Name: SIGSBEE PARK, GARRISON BIGHT CHANNEL
FLORIDA
NOAA Chart: 11441 Latitude: 24° 35.1' N
USGS Quad: KEY WEST Longitude: 81° 46.5' W
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 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.