U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 8724368 PUBLICATION DATE: 02/05/2004
Name: SUGARLOAF KEY (NORTH END)
FL
NOAA Chart: 11445 Latitude: 24° 41.6' N ( 24.69330)
USGS Quad: SUGARLOAF KEY Longitude: 81° 33.3' W ( -81.55500)
To reach the tidal bench marks from the U.S. Highway 1 bridge over Sugarloaf
Channel, proceed by boat NW on Sugarloaf Channel for 4.5 km (2.4 nm) to the
north end of Sugarloaf Key. The bench marks are located in the mangrove of the
north end of the Key, and may be inundated at high tide. The tide gage and
staff were located offshore, NE of the north 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 1973
DESIGNATION: 872 4368 TIDAL 1
MONUMENTATION: Tidal Station disk VM#: 7011
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 24° 41.6' N ( 24.69330) LONGITUDE: 81° 33.3' W ( -81.55500)
The primary bench mark is a disk set in a concrete monument on the extreme north
point of Sugarloaf Key, 78 m (256 ft) SW of the northern point of the Key, 49.99
m (164.0 ft) east of the west shoreline, 7.53 m (24.7 ft) south of bench mark
SUGAR 1934, and 0.09 m (0.3 ft) above ground level.
BENCH MARK STAMPING: NO 2 1973
DESIGNATION: 872 4368 TIDAL 2
MONUMENTATION: Tidal Station disk VM#: 7012
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 24° 41.6' N ( 24.69330) LONGITUDE: 81° 33.3' W ( -81.55500)
The bench mark is a disk set in a concrete monument, 70 m (230 ft) south of the
NE end of the Key, 56 m (184 ft) east of the west shoreline of the Key, 8.29 m
(27.2 ft) north of bench mark NO 1 1973, 4.60 m (15.1 ft) NE of bench mark SUGAR
1934, and 0.06 m (0.2 ft) above ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 8724368 PUBLICATION DATE: 02/05/2004
Name: SUGARLOAF KEY (NORTH END)
FL
NOAA Chart: 11445 Latitude: 24° 41.6' N ( 24.69330)
USGS Quad: SUGARLOAF KEY Longitude: 81° 33.3' W ( -81.55500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 3 1973
DESIGNATION: 872 4368 TIDAL 3
MONUMENTATION: Tidal Station disk VM#: 7013
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 24° 41.6' N ( 24.69330) LONGITUDE: 81° 33.3' W ( -81.55500)
The bench mark is a disk set in a concrete monument, 70 m (230 ft) SE of the NE
end of the Key, 40 m (131 ft) east of the west shoreline of the Key, 13.84 m
(45.4 ft) SW of bench mark NO 2 1973, 11.52 m (37.8 ft) west of bench mark NO 1
1973, 9.30 m (30.5 ft) SW of bench mark SUGAR 1934, and 0.06 m (0.2 ft) above
ground level.
BENCH MARK STAMPING: NO 4 1973
DESIGNATION: 872 4368 TIDAL 4
MONUMENTATION: Tidal Station disk VM#: 7014
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 24° 41.6' N ( 24.69330) LONGITUDE: 81° 33.3' W ( -81.55500)
The bench mark is a disk set in a concrete monument, 62 m (203 ft) SE of the NE
end of the Key, 50 m (164 ft) east of the west shoreline of the Key, 15.15 m
(49.7 ft) NW of bench mark NO 1 1973, 13.05 m (42.8 ft) NNE of bench mark NO 3
1973, 9.02 m (29.6 ft) ESE of bench mark NO 2 1973, and 0.06 m (0.2 ft) above
ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 8724368 PUBLICATION DATE: 02/05/2004
Name: SUGARLOAF KEY (NORTH END)
FL
NOAA Chart: 11445 Latitude: 24° 41.6' N ( 24.69330)
USGS Quad: SUGARLOAF KEY Longitude: 81° 33.3' W ( -81.55500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: SUGAR 1934
DESIGNATION: SUGAR 1934
MONUMENTATION: Survey disk VM#: 7015
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: AA1028
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 24° 41.6' N ( 24.69330) LONGITUDE: 81° 33.3' W ( -81.55500)
The bench mark is a disk set in a 0.24 m (0.8 ft) square concrete monument, 70 m
(230 ft) south of the north end of the Key, 50 m (164 ft) east of the west
shoreline of the Key, 7.62 m (25.0 ft) SE of bench mark NO 4 1973, and 0.24 m
(0.8 ft) above ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 8724368 PUBLICATION DATE: 02/05/2004
Name: SUGARLOAF KEY (NORTH END)
FL
NOAA Chart: 11445 Latitude: 24° 41.6' N ( 24.69330)
USGS Quad: SUGARLOAF KEY Longitude: 81° 33.3' W ( -81.55500)
T I D A L D A T U M S
Tidal datums at SUGARLOAF KEY (NORTH END) based on:
LENGTH OF SERIES: 3 MONTHS
TIME PERIOD: December 1973 - February 1974
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 = 0.687
MEAN HIGH WATER MHW = 0.598
MEAN TIDE LEVEL MTL = 0.327
MEAN SEA LEVEL MSL = 0.291
MEAN LOW WATER MLW = 0.056
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 1973 0.551 -0.047
NO 2 1973 0.550 -0.048
NO 3 1973 0.480 -0.118
NO 4 1973 0.553 -0.045
SUGAR 1934 0.670 0.072
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 8724368 PUBLICATION DATE: 02/05/2004
Name: SUGARLOAF KEY (NORTH END)
FL
NOAA Chart: 11445 Latitude: 24° 41.6' N ( 24.69330)
USGS Quad: SUGARLOAF KEY Longitude: 81° 33.3' W ( -81.55500)
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.