U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
PUBLICATION DATE: 05/27/1986
Station ID: 8724405 SUPERCEDED DATE: 04/21/2003
Name: SADDLEBUNCH KEY, CHANNEL NO 3
FLORIDA
NOAA Chart: 11442 Latitude: 24° 37.4' N
USGS Quad: SUGARLOAF KEY Longitude: 81° 36.2' W
To reach the tidal bench marks from the Catholic Church in Key West, proceed
13.45 miles (21.5 km) NE on U.S. Highway 1 to the NE end of the bridge over
Saddlebunch Key, Channel No. 3. The bench marks are in the vicinity of old U.S.
Highway 1 bridge (fishing pier). The tide gage and staff were located on the NE
wingwall of the NE end of the old bridge (fishing pier).
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: NO 1 1975
MONUMENTATION: Survey Disk VM#: 7816
AGENCY: PID#: AA0774
SETTING CLASSIFICATION: Concrete Wingwall
The bench mark is set flush in the north concrete wingwall of the old U.S.
Highway 1 bridge (fishing pier), 15 feet (5 m) NW of the centerline of the old
bridge (fishing pier), and 3 feet (1 m) below the old bridge (fishing pier).
BENCH MARK STAMPING: NO 2 1975
MONUMENTATION: Survey Disk VM#: 7817
AGENCY: PID#: AA0773
SETTING CLASSIFICATION: Concrete Wingwall
The bench mark is set flush in the south concrete wingwall of the old U.S.
Highway 1 bridge (fishing pier), 30.5 feet (9.3 m) SE of Bench Mark NO 1 1975,
15.5 feet (4.7 m) SE of the centerline of the old bridge (fishing pier), 13.5
feet (4.1 m) SW of a sign FAP 107-C, 3.5 feet (1.1 m) SE of the SE edge of the
old bridge (fishing pier), and 1 foot (0.3 m) below the old bridge (fishing
pier).
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
PUBLICATION DATE: 05/27/1986
Station ID: 8724405 SUPERCEDED DATE: 04/21/2003
Name: SADDLEBUNCH KEY, CHANNEL NO 3
FLORIDA
NOAA Chart: 11442 Latitude: 24° 37.4' N
USGS Quad: SUGARLOAF KEY Longitude: 81° 36.2' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 3 1975
MONUMENTATION: Survey Disk VM#: 7818
AGENCY: PID#: AA0776
SETTING CLASSIFICATION: Concrete Footing
The bench mark is set flush in the NW corner of the concrete footing of concrete
power pole T 741, 81 feet (25 m) NE of Bench Mark NO 2 1975, 42.5 feet (13.0 m)
SE of the extended centerline of the old bridge (fishing pier), and 6 feet (2 m)
below the old bridge (fishing pier).
BENCH MARK STAMPING: NO 4 1975
MONUMENTATION: Survey Disk VM#: 7819
AGENCY: PID#: AA0777
SETTING CLASSIFICATION: Copper-coated Steel Rod
The bench mark is 0.1 mile (0.2 km) NE from the U.S. Highway 1 bridge over
Saddlebunch Key, Channel No. 3 to Blue Water Drive, then 0.05 mile (0.08 km)
south on Blue Water Drive, 22 feet (7 m) SE of the centerline of Blue Water
Drive, and 1 foot (0.3 m) NW of a wooden telephone pole. The bench mark is 6
inches (0.15 m) above ground, crimped to a cooper-coated steel rod driven to
refusal, encased in a PVC pipe and concrete kickblock.
BENCH MARK STAMPING: NO 5 1975
MONUMENTATION: Survey Disk VM#: 7820
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Telephone Pole
The bench mark is set flush at the NW corner of the concrete base of a concrete
telephone pole No. TT 1-47, 108 feet (33 m) north of Bench Mark NO 4 1975, 29
feet (9 m) SW of the centerline of Blue Water Drive, and 25 feet (8 m) SE of
U.S. Highway 1.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
PUBLICATION DATE: 05/27/1986
Station ID: 8724405 SUPERCEDED DATE: 04/21/2003
Name: SADDLEBUNCH KEY, CHANNEL NO 3
FLORIDA
NOAA Chart: 11442 Latitude: 24° 37.4' N
USGS Quad: SUGARLOAF KEY Longitude: 81° 36.2' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 4405 F
MONUMENTATION: Survey Disk VM#: 7821
AGENCY: PID#: AA0775
SETTING CLASSIFICATION: Concrete Bridge Guardrail
The bench mark is set on a concrete guardrail, 23.3 feet (7.1 m) SE of the
centerline of U.S. Highway 1, 10.5 feet (3.2 m) SW of the NE end of the
guardrail, 4.9 feet (1.5 m) NW of the SE edge of the U.S. Highway 1 bridge
cheekwall, 0.5 feet (0.15 m) NE of the NE abutment, and 3 feet (1 m) above U.S.
Highway 1.
BENCH MARK STAMPING: S 70 RESET 1939
MONUMENTATION: Survey Disk VM#: 7822
AGENCY: PID#: AA0118
SETTING CLASSIFICATION: Concrete Wingwall
The bench mark is set on top of the south concrete wingwall at the SW end of the
old U.S. Highway 1 bridge (fishing pier), 14.5 feet (4.4 m) SE of the centerline
of old U.S. Highway 1, and 3 feet (1 m) below the old bridge (fishing pier).
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
PUBLICATION DATE: 05/27/1986
Station ID: 8724405 SUPERCEDED DATE: 04/21/2003
Name: SADDLEBUNCH KEY, CHANNEL NO 3
FLORIDA
NOAA Chart: 11442 Latitude: 24° 37.4' N
USGS Quad: SUGARLOAF KEY Longitude: 81° 36.2' W
T I D A L D A T U M S
Tidal datums at SADDLEBUNCH KEY, CHANNEL NO 3 based on:
LENGTH OF SERIES: 1 MONTH
TIME PERIOD: FEBRUARY 1975
TIDAL EPOCH: 1960-1978
CONTROL TIDE STATION: 8724211 BIG PINE KEY VIADUCT
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET:
HIGHEST OBSERVED WATER LEVEL (02/25/1975) = 1.59
MEAN HIGHER HIGH WATER MHHW = 0.92
MEAN HIGH WATER MHW = 0.67
MEAN TIDE LEVEL MTL = 0.36
MEAN LOW WATER MLW = 0.05
MEAN LOWER LOW WATER MLLW = 0.00
LOWEST OBSERVED WATER LEVEL (01/23/1975) = -0.39
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In FEET above:
Stamping or Designation MLLW MHW
NO 1 1975 7.97 7.30
NO 2 1975 7.95 7.28
NO 3 1975 3.37 2.70
NO 4 1975 3.51 2.84
NO 5 1975 3.31 2.64
4405 F 15.97 15.30
S 70 RESET 1939 8.04 7.37
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
PUBLICATION DATE: 05/27/1986
Station ID: 8724405 SUPERCEDED DATE: 04/21/2003
Name: SADDLEBUNCH KEY, CHANNEL NO 3
FLORIDA
NOAA Chart: 11442 Latitude: 24° 37.4' N
USGS Quad: SUGARLOAF KEY Longitude: 81° 36.2' 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.