U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 9
Station ID: 8724635 PUBLICATION DATE: 02/18/2005
Name: SAND KEY LIGHTHOUSE
FL
NOAA Chart: 11441 Latitude: 24° 27.2' N ( 24.45330)
USGS Quad: NA Longitude: 81° 52.7' W ( -81.87830)
To reach the tidal bench marks from the SW corner of Fort Zachary Taylor State
Park in Key West, proceed by boat SW for 12.0 km (7.5 statute mi) to Sand Key
Lighthouse. The bench marks are on the legs and at the corners of the
lighthouse. The tide gage and staff were on the east side of the boathouse on
the end of the pier west of the lighthouse.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: NO 1
DESIGNATION: 872 4635 NUT 1
MONUMENTATION: See descriptive text VM#: 9681
AGENCY: IDB PID#:
SETTING CLASSIFICATION: Tower leg OPUS PID:
LATITUDE: 24° 27.2' N ( 24.45330) LONGITUDE: 81° 52.7' W ( -81.87830)
The primary bench mark is the high point of the southernmost nut of four nuts on
a joint, on the south side of the first leg north of the west corner leg of the
structure, and 1.49 m (4.9 ft) below the top of the pier that leads to the
boathouse on the west side of the lighthouse.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 9
Station ID: 8724635 PUBLICATION DATE: 02/18/2005
Name: SAND KEY LIGHTHOUSE
FL
NOAA Chart: 11441 Latitude: 24° 27.2' N ( 24.45330)
USGS Quad: NA Longitude: 81° 52.7' W ( -81.87830)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 2
DESIGNATION: 872 4635 PIN 2
MONUMENTATION: See descriptive text VM#: 9682
AGENCY: IDB PID#:
SETTING CLASSIFICATION: Tower leg OPUS PID:
LATITUDE: 24° 27.2' N ( 24.45330) LONGITUDE: 81° 52.7' W ( -81.87830)
The bench mark is the high point of the head of the southernmost pin of four
pins used to fasten diagonal members of the tower, on the first internal leg NE
of the pier, 5.39 m (17.7 ft) ESE of Bench Mark NO 1, and 1.28 m (4.2 ft) below
pier level. NOTE: The head of the pin is 4 inches in diameter and 0.75 inch
high.
BENCH MARK STAMPING: NO 3
DESIGNATION: 872 4635 NUT 3
MONUMENTATION: See descriptive text VM#: 9683
AGENCY: IDB PID#:
SETTING CLASSIFICATION: Tower leg OPUS PID:
LATITUDE: 24° 27.2' N ( 24.45330) LONGITUDE: 81° 52.7' W ( -81.87830)
The bench mark is the high point of the easternmost nut of four nuts on a joint,
on the first outside leg SE of the west corner leg of the structure, 7.62 m
(25.0 ft) south of Bench Mark NO 1, 5.00 m (16.4 ft) SSW of Bench Mark NO 2, and
1.49 m (4.9 ft) below pier level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 9
Station ID: 8724635 PUBLICATION DATE: 02/18/2005
Name: SAND KEY LIGHTHOUSE
FL
NOAA Chart: 11441 Latitude: 24° 27.2' N ( 24.45330)
USGS Quad: NA Longitude: 81° 52.7' W ( -81.87830)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 4
DESIGNATION: 872 4635 NUT 4
MONUMENTATION: See descriptive text VM#: 9684
AGENCY: IDB PID#:
SETTING CLASSIFICATION: Tower leg OPUS PID:
LATITUDE: 24° 27.2' N ( 24.45330) LONGITUDE: 81° 52.7' W ( -81.87830)
The bench mark is the high point of the westernmost nut of four nuts on a joint,
on the second outside leg SE of the west corner leg of the structure, 6.86 m
(22.5 ft) south of Bench Mark NO 2, and 1.49 m (4.9 ft) below pier level.
BENCH MARK STAMPING: NO 5
DESIGNATION: 872 4635 NUT 5
MONUMENTATION: See descriptive text VM#: 9685
AGENCY: IDB PID#:
SETTING CLASSIFICATION: Tower leg OPUS PID:
LATITUDE: 24° 27.2' N ( 24.45330) LONGITUDE: 81° 52.7' W ( -81.87830)
The bench mark is the high point of the SE most nut of four nuts on a joint, on
the southernmost leg (third leg SE of the west corner leg) of the structure,
11.46 m (37.6 ft) ESE of Bench Mark NO 2, 5.67 m (18.6 ft) SE of Bench Mark NO
4, and 1.49 m (4.9 ft) below pier level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 9
Station ID: 8724635 PUBLICATION DATE: 02/18/2005
Name: SAND KEY LIGHTHOUSE
FL
NOAA Chart: 11441 Latitude: 24° 27.2' N ( 24.45330)
USGS Quad: NA Longitude: 81° 52.7' W ( -81.87830)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING:
DESIGNATION: 872 4635 B
ALIAS: B
MONUMENTATION: See descriptive text VM#: 9686
AGENCY: IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 24° 27.2' N ( 24.45330) LONGITUDE: 81° 52.7' W ( -81.87830)
The bench mark is the highest point of a stainless steel rod, located inside the
west corner of the lighthouse, 3 m (10 ft) SW of the SW side of the first leg NE
of the west leg, and 0.98 m (3.2 ft) east of the east side of the west leg. The
bench mark is 0.27 m (0.9 ft) above the ground and is the highest point of a
stainless steel rod driven to a depth of 16 m (52 ft), and encased in a PVC pipe
and concrete kickblock. NOTE: Designated Bench Mark 4635 B
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 9
Station ID: 8724635 PUBLICATION DATE: 02/18/2005
Name: SAND KEY LIGHTHOUSE
FL
NOAA Chart: 11441 Latitude: 24° 27.2' N ( 24.45330)
USGS Quad: NA Longitude: 81° 52.7' W ( -81.87830)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING:
DESIGNATION: 872 4635 C
ALIAS: C
MONUMENTATION: See descriptive text VM#: 9687
AGENCY: IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 24° 27.2' N ( 24.45330) LONGITUDE: 81° 52.7' W ( -81.87830)
The bench mark is the highest point of a stainless steel rod, located inside the
north corner of the lighthouse, 344 m (11.3 ft) NW of the NW side of the first
leg SE of the north corner leg, and 0.46 m (1.5 ft) SE of the SE side of the
north leg. The bench mark is 0.24 m (0.8 ft) above the ground and is the
highest point of a stainless steel rod driven to a depth of 24 m (80 ft), and
encased in a PVC pipe and concrete kickblock. NOTE: Designated Bench Mark 4635
C
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 9
Station ID: 8724635 PUBLICATION DATE: 02/18/2005
Name: SAND KEY LIGHTHOUSE
FL
NOAA Chart: 11441 Latitude: 24° 27.2' N ( 24.45330)
USGS Quad: NA Longitude: 81° 52.7' W ( -81.87830)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING:
DESIGNATION: 872 4635 D
ALIAS: D
MONUMENTATION: See descriptive text VM#: 9688
AGENCY: IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 24° 27.2' N ( 24.45330) LONGITUDE: 81° 52.7' W ( -81.87830)
The bench mark is the highest point of a stainless steel rod, located inside the
east corner of the lighthouse, 3.14 m (10.3 ft) NE of the NE side of the first
leg SW of the east corner leg, and 0.85 m (2.8 ft) WSW of the east corner leg.
The bench mark is 0.43 m (1.4 ft) above the ground and is the highest point of a
stainless steel rod driven to a depth of 24 m (80 ft), and encased in a PVC pipe
and concrete kickblock. NOTE: Designated Bench Mark 4635 D
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 7 of 9
Station ID: 8724635 PUBLICATION DATE: 02/18/2005
Name: SAND KEY LIGHTHOUSE
FL
NOAA Chart: 11441 Latitude: 24° 27.2' N ( 24.45330)
USGS Quad: NA Longitude: 81° 52.7' W ( -81.87830)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING:
DESIGNATION: 872 4635 E
ALIAS: E
MONUMENTATION: See descriptive text VM#: 9689
AGENCY: IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 24° 27.2' N ( 24.45330) LONGITUDE: 81° 52.7' W ( -81.87830)
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 8 of 9
Station ID: 8724635 PUBLICATION DATE: 02/18/2005
Name: SAND KEY LIGHTHOUSE
FL
NOAA Chart: 11441 Latitude: 24° 27.2' N ( 24.45330)
USGS Quad: NA Longitude: 81° 52.7' W ( -81.87830)
T I D A L D A T U M S
Tidal datums at SAND KEY LIGHTHOUSE based on:
LENGTH OF SERIES: 2 Months
TIME PERIOD: March 2000 - April 2000
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 = 0.530
MEAN HIGH WATER MHW = 0.442
MEAN SEA LEVEL MSL = 0.261
MEAN TIDE LEVEL MTL = 0.254
MEAN LOW WATER MLW = 0.065
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 0.971 0.529
NO 2 1.205 0.763
NO 3 0.963 0.521
NO 4 0.984 0.542
NO 5 0.993 0.551
872 4635 B -0.162 -0.604
872 4635 C 0.129 -0.313
872 4635 D 0.055 -0.387
872 4635 E -0.176 -0.618
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 9 of 9
Station ID: 8724635 PUBLICATION DATE: 02/18/2005
Name: SAND KEY LIGHTHOUSE
FL
NOAA Chart: 11441 Latitude: 24° 27.2' N ( 24.45330)
USGS Quad: NA Longitude: 81° 52.7' W ( -81.87830)
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.