U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 4
Station ID: 8724353 PUBLICATION DATE: 07/12/2004
Name: PERKY LAKE, SUGERLOAF KEY
FL
NOAA Chart: 11434 Latitude: 24° 39.3' N ( 24.65500)
USGS Quad: SUGARLOAF KEY Longitude: 81° 32.4' W ( -81.54000)
To reach the tidal bench marks from the post office in Sugarloaf Shores, proceed
NE on U.S. Highway 1 for 2.6 km (1.6 mi) to the bridge over Park Channel. The
bench marks are located in the area around the old 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: Bench Mark disk VM#: 6997
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: AA0143
SETTING CLASSIFICATION: Wing wall OPUS PID:
LATITUDE: 24° 39.3' N ( 24.65500) LONGITUDE: 81° 32.4' W ( -81.54000)
The primary bench mark is a disk set in the top of the SE wing wall for the old
Park Channel bridge, 29 km (18 mi) NE along U.S. Highway 1 from the Catholic
Church at Key West, and 5 m (15 ft) SE of the centerline of the highway.
BENCH MARK STAMPING: NO 1 1973
MONUMENTATION: Tidal Station disk VM#: 6998
AGENCY: National Ocean Survey (NOS) IDB PID#: AA0757
SETTING CLASSIFICATION: Wing wall OPUS PID:
LATITUDE: 24° 39.3' N ( 24.65500) LONGITUDE: 81° 32.4' W ( -81.54000)
The bench mark is a disk set in the south wing wall at the NE end of the old
highway bridge, now used as a fishing pier, 13.26 m (43.5 ft) SSE of the
centerline of the old bridge, and 9.02 m (29.6 ft) NW of the SE end of the wing
wall.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 4
Station ID: 8724353 PUBLICATION DATE: 07/12/2004
Name: PERKY LAKE, SUGERLOAF KEY
FL
NOAA Chart: 11434 Latitude: 24° 39.3' N ( 24.65500)
USGS Quad: SUGARLOAF KEY Longitude: 81° 32.4' W ( -81.54000)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 4353 D
MONUMENTATION: Triangulation Station disk VM#: 6999
AGENCY: Florida Department of Transportation
(FLDOT) IDB PID#: AA0758
SETTING CLASSIFICATION: Bridge guardrail OPUS PID:
LATITUDE: 24° 39.3' N ( 24.65500) LONGITUDE: 81° 32.4' W ( -81.54000)
The bench mark is a disk set in the top of the bridge guardrail, 7.16 m (23.5
ft) NW of the centerline of U.S. Highway 1, 2.74 m (9.0 ft) SW of the NE end of
the concrete guard rail, 0.30 m (1.0 ft) NE of the NE abutment, and 1 m (3 ft)
above the level of the highway.
BENCH MARK STAMPING: 4353 E
MONUMENTATION: Tidal Station disk VM#: 7000
AGENCY: Florida Department of Transportation
(FLDOT) IDB PID#: AA0756
SETTING CLASSIFICATION: Bridge guardrail OPUS PID:
LATITUDE: 24° 39.3' N ( 24.65500) LONGITUDE: 81° 32.4' W ( -81.54000)
The bench mark is a disk set in the top of the bridge guardrail, 7.13 m (23.4
ft) SE of the centerline of U.S. Highway 1, 2.71 m (8.9 ft) NE of the SW end of
the guardrail, 0.34 m (1.1 ft) SW of the SW abutment, and 1 m (3 ft) above the
level of the highway.
BENCH MARK STAMPING: C 272 1966
MONUMENTATION: Bench Mark disk VM#: 17277
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: AA0140
SETTING CLASSIFICATION: Bridge curb OPUS PID:
LATITUDE: 24° 39.3' N ( 24.65500) LONGITUDE: 81° 32.5' W ( -81.54170)
The bench mark is a disk set in top of the curb for the old Park Channel bridge,
at the west end of the old bridge, 4 m (12 ft) north of the centerline of the
bridge. Note: The edge of the bench mark has been sheared off.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 4
Station ID: 8724353 PUBLICATION DATE: 07/12/2004
Name: PERKY LAKE, SUGERLOAF KEY
FL
NOAA Chart: 11434 Latitude: 24° 39.3' N ( 24.65500)
USGS Quad: SUGARLOAF KEY Longitude: 81° 32.4' W ( -81.54000)
D A T U M S
Datums at PERKY LAKE, SUGERLOAF KEY based on:
LENGTH OF SERIES: 2 MONTHS
TIME PERIOD: January 1974 - February 1974
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8724580 KEY WEST
Elevations of datums referred to Mean Lower Low Water (MLLW), in METERS:
North American Vertical Datum NAVD88 = 0.194
MEAN HIGHER HIGH WATER MHHW = 0.159
MEAN HIGH WATER MHW = 0.121
MEAN TIDE LEVEL MTL = 0.070
MEAN SEA LEVEL MSL = 0.068
MEAN LOW WATER MLW = 0.018
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
P 70 RESET 1938 2.200 2.079
NO 1 1973 1.410 1.289
4353 D 4.674 4.553
4353 E 4.665 4.544
C 272 1966 3.393 3.272
Foot Notes:
Bench marks 4353 D, 4353 E, and C 272 1966 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 4 of 4
Station ID: 8724353 PUBLICATION DATE: 07/12/2004
Name: PERKY LAKE, SUGERLOAF KEY
FL
NOAA Chart: 11434 Latitude: 24° 39.3' N ( 24.65500)
USGS Quad: SUGARLOAF KEY Longitude: 81° 32.4' W ( -81.54000)
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.