U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 4
PUBLICATION DATE: 10/15/1987
Station ID: 8724353 SUPERCEDED DATE: 04/21/2003
Name: PERKY LAKE, SUGARLOAF KEY
FLORIDA
NOAA Chart: 11434 Latitude: 24° 39.3' N
USGS Quad: SUGARLOAF KEY Longitude: 81° 32.4' W
To reach the tidal bench marks from the post office in Sugarloaf Shores, proceed
1.6 miles (2.6 km) NE on U.S. Highway 1 to the bridge over Park Channel. The
bench marks are located in the area around the bridge. The tide gage and staff
were located on the NE abutment of the Park Channel bridge.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: P 70 RESET 1938
MONUMENTATION: Survey Disk VM#: 6997
AGENCY: PID#: AA0143
SETTING CLASSIFICATION: Concrete Wingwall
The bench mark is set in the top of the SE wingwall at the Park Key Viaduct, 18
miles (29.0 km) NE along U.S. Highway 1 from the Catholic Church at Key West,
and 15 feet (5 m) SE of the centerline of the highway.
BENCH MARK STAMPING: NO 1 1973
MONUMENTATION: Survey Disk VM#: 6998
AGENCY: PID#: AA0757
SETTING CLASSIFICATION: Concrete Wingwall
The bench mark is set in the south wingwall at the NE end of the old highway
bridge, now used as a fishing pier, 43.5 feet (13.3 m) SSE of the centerline of
the old bridge, and 29.6 feet (9.0 m) NW of the SE end of the wingwall.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 4
PUBLICATION DATE: 10/15/1987
Station ID: 8724353 SUPERCEDED DATE: 04/21/2003
Name: PERKY LAKE, SUGARLOAF KEY
FLORIDA
NOAA Chart: 11434 Latitude: 24° 39.3' N
USGS Quad: SUGARLOAF KEY Longitude: 81° 32.4' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 4353 D
MONUMENTATION: Survey Disk VM#: 6999
AGENCY: PID#: AA0758
SETTING CLASSIFICATION: Concrete Guard Rail
The bench mark is 23.5 feet (7.2 m) NW of the centerline of U.S. Highway 1, 9.0
feet (2.7 m) SW of the NE end of the concrete guard rail, and 1.0 foot (0.3 m)
NE of the NE abutment.
BENCH MARK STAMPING: 4353 E
MONUMENTATION: Survey Disk VM#: 7000
AGENCY: PID#: AA0756
SETTING CLASSIFICATION: Concrete Guard Rail
The bench mark is 23.4 feet (7.1 m) SE of the centerline of U.S. Highway 1, 8.9
feet (2.7 m) NE of the SW end of the concrete guard rail, and 1.1 feet (0.3 m)
SW of the SW abutment.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 4
PUBLICATION DATE: 10/15/1987
Station ID: 8724353 SUPERCEDED DATE: 04/21/2003
Name: PERKY LAKE, SUGARLOAF KEY
FLORIDA
NOAA Chart: 11434 Latitude: 24° 39.3' N
USGS Quad: SUGARLOAF KEY Longitude: 81° 32.4' W
T I D A L D A T U M S
Tidal datums at PERKY LAKE, SUGARLOAF KEY based on:
LENGTH OF SERIES: 2 MONTHS
TIME PERIOD: JANUARY-FEBRUARY 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 (12/16/1973) = 1.61
MEAN HIGHER HIGH WATER MHHW = 0.54
MEAN HIGH WATER MHW = 0.41
MEAN TIDE LEVEL MTL = 0.24
MEAN LOW WATER MLW = 0.07
MEAN LOWER LOW WATER MLLW = 0.00
* NATIONAL GEODETIC VERTICAL DATUM NGVD29 = -0.51
LOWEST OBSERVED WATER LEVEL (03/01/1974) = -0.44
* NGVD reference based on elevations published in Quad 240814, 1971, and NOS
leveling of 1982.
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In FEET above:
Stamping or Designation MLLW MHW
P 70 RESET 1938 7.44 7.03
NO 1 1973 4.85 4.44
4353 D 15.56 15.15
4353 E 15.53 15.12
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 4
PUBLICATION DATE: 10/15/1987
Station ID: 8724353 SUPERCEDED DATE: 04/21/2003
Name: PERKY LAKE, SUGARLOAF KEY
FLORIDA
NOAA Chart: 11434 Latitude: 24° 39.3' N
USGS Quad: SUGARLOAF KEY Longitude: 81° 32.4' 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.