U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 6
Station ID: 8723962 PUBLICATION DATE: 04/21/2003
Name: KEY COLONY BEACH
FL
NOAA Chart: 11449 Latitude: 24° 43.1' N ( 24.71830)
USGS Quad: MARATHON Longitude: 81° 1.0' W ( -81.01670)
To reach the tidal bench marks from Marathon, proceed NE on U.S. 1 to the
intersection with Key Colony Beach Road (Sudowski Causeway), turn south onto
Sudowski Causeway and proceed 1.4 km (0.9 mi) to Sunset Beach Club Apartments.
The bench marks are located along Sudowski Causeway and U.S. 1. The tide
station is located on the SE end of the Sunset Beach Club pier.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: A 3962 1976
DESIGNATION: 872 3962 A TIDAL
MONUMENTATION: Tidal Station disk VM#: 678
AGENCY: National Ocean Survey (NOS) IDB PID#: AA0883
SETTING CLASSIFICATION: Retaining wall OPUS PID:
LATITUDE: 24° 43.3' N ( 24.72170) LONGITUDE: 81° 1.1' W ( -81.01830)
The primary bench mark is a disk set flush in the south end of the concrete sea
wall on the west side of a chainlink fence and the west side of the apartments,
11.13 m (36.5 ft) SW of the SW corner of the most southwestern apartment
building, and 4.70 m (15.4 ft) west of the center of the walkway to the pier.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 6
Station ID: 8723962 PUBLICATION DATE: 04/21/2003
Name: KEY COLONY BEACH
FL
NOAA Chart: 11449 Latitude: 24° 43.1' N ( 24.71830)
USGS Quad: MARATHON Longitude: 81° 1.0' W ( -81.01670)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: B 3962 1976
DESIGNATION: 872 3962 B TIDAL
MONUMENTATION: Tidal Station disk VM#: 679
AGENCY: National Ocean Survey (NOS) IDB PID#: AA0882
SETTING CLASSIFICATION: Retaining wall OPUS PID:
LATITUDE: 24° 43.3' N ( 24.72170) LONGITUDE: 81° 1.1' W ( -81.01830)
The bench mark is a disk set near the north end of a concrete sea wall on the
west side of the apartments at the south end of Sudowski Causeway, 13.80 m (
45.2 ft) NW of the west corner of the southwestern-most apartment building, 8.70
m (28.5 ft) SW of the west corner of the swimming pool storage building, and
7.32 m (24.0 ft) SE of the northern end of the sea wall.
BENCH MARK STAMPING: 3962 K 1978
DESIGNATION: 872 3962 K TIDAL
MONUMENTATION: Tidal Station disk VM#: 683
AGENCY: National Ocean Survey (NOS) IDB PID#: AA0881
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 24° 43.3' N ( 24.72170) LONGITUDE: 81° 1.1' W ( -81.01830)
The bench mark is a disk located 30.18 m (99.0 ft) SW of the L-Junction of
Sudowski Causeway and East Ocean Drive, 4.80 m (15.7 ft) west of the NW corner
of the apartments, and 0.24 m (0.8 ft) SE of a light pole and a wood fence for
lawn storage. The bench mark projects 0.15 m (0.5 ft) above ground, crimped to
the end of a stainless steel rod driven 5.50 m (18.0 ft) to refusal, and encased
in a 5-inch PVC pipe and concrete kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 6
Station ID: 8723962 PUBLICATION DATE: 04/21/2003
Name: KEY COLONY BEACH
FL
NOAA Chart: 11449 Latitude: 24° 43.1' N ( 24.71830)
USGS Quad: MARATHON Longitude: 81° 1.0' W ( -81.01670)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 3962 G 1984
DESIGNATION: 872 3962 G TIDAL
MONUMENTATION: Tidal Station disk VM#: 685
AGENCY: National Ocean Service (NOS) IDB PID#: AA1711
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 24° 43.5' N ( 24.72500) LONGITUDE: 81° 1.1' W ( -81.01830)
The bench mark is a disk located 105 m (345 ft) NNW of the north end of the sea
wall at the Key Colony Beach Commercial Marina, 17.40 m (57.0 ft) west of the SW
corner of the residence of # 7 Key Colony Beach Road, 11.30 m (37.0 ft) SSW of a
power/street light pole, 6.40 m (21.0 ft) west of the centerline for Key Colony
Beach Road and 1.01 m (3.3 ft) west of the west edge of a bike path. The bench
mark is set 0.09 m (0.3 ft) below ground, crimped to the end of a stainless
steel rod driven 7.30 m (24.0 ft) to refusal, and encased in a 5-inch PVC pipe
and concrete kickblock with an aluminum access cover stamped 3962 G 1984.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 6
Station ID: 8723962 PUBLICATION DATE: 04/21/2003
Name: KEY COLONY BEACH
FL
NOAA Chart: 11449 Latitude: 24° 43.1' N ( 24.71830)
USGS Quad: MARATHON Longitude: 81° 1.0' W ( -81.01670)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING:
DESIGNATION: 872 3962 NE TIDAL FLDT
ALIAS: NO STAMPING 2
MONUMENTATION: Bench Mark disk VM#: 687
AGENCY: Florida Department of Transportation
(FLDT) IDB PID#: AA0876
SETTING CLASSIFICATION: Retaining wall OPUS PID:
LATITUDE: 24° 43.7' N ( 24.72830) LONGITUDE: 81° 1.2' W ( -81.02000)
The bench mark is a disk set in the abutment at the NW end of a small bridge on
Sudowski Causeway, 17.53 m (57.5 ft) NW of the first power pole SE of the bridge
on the NE side of the road, and 4.21 m (13.8 ft) NE of the centerline of the
road.
BENCH MARK STAMPING: 3962 L 1988
DESIGNATION: 872 3962 L TIDAL
MONUMENTATION: Tidal Station disk VM#: 1780
AGENCY: National Ocean Service (NOS) IDB PID#: AA1713
SETTING CLASSIFICATION: Concrete foundation OPUS PID:
LATITUDE: 24° 43.4' N ( 24.72330) LONGITUDE: 81° 1.1' W ( -81.01830)
The bench mark is a disk set in the top of a concrete foundation for a fuel tank
retaining wall on the south side of Key Colony Beach Commercial Marina, 39.47 m
(129.5 ft) east of the centerline of Sudowski Causeway, 17.43 m (57.2 ft) NE of
the NE corner of the Key Colony Beach Shopping Center building, 4.05 m (13.3 ft)
west of the east face of the sea wall along the marina canal, 0.85 m (2.8 ft)
west of the SE corner of the concrete retaining wall, and 0.06 m (0.2 ft) above
the ground.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 6
Station ID: 8723962 PUBLICATION DATE: 04/21/2003
Name: KEY COLONY BEACH
FL
NOAA Chart: 11449 Latitude: 24° 43.1' N ( 24.71830)
USGS Quad: MARATHON Longitude: 81° 1.0' W ( -81.01670)
T I D A L D A T U M S
Tidal datums at KEY COLONY BEACH based on:
LENGTH OF SERIES: 19 Years
TIME PERIOD: 4/1977-3/1989 ; 12/1989-11/1991 ; 4/1993-3/1995
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8724580 KEY WEST
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
HIGHEST OBSERVED WATER LEVEL (10/10/1990) = 0.985
MEAN HIGHER HIGH WATER MHHW = 0.632
North American Vertical Datum NAVD88 = 0.624
MEAN HIGH WATER MHW = 0.566
MEAN SEA LEVEL MSL = 0.320
MEAN TIDE LEVEL MTL = 0.313
MEAN LOW WATER MLW = 0.060
MEAN LOWER LOW WATER MLLW = 0.000
LOWEST OBSERVED WATER LEVEL (04/07/1985) = -0.569
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
A 3962 1976 1.707 1.141
B 3962 1976 1.707 1.141
3962 K 1978 1.943 1.377
3962 G 1984 1.183 0.617
872 3962 NE TIDAL FLDT 2.518 1.952
3962 L 1988 1.528 0.962
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 6
Station ID: 8723962 PUBLICATION DATE: 04/21/2003
Name: KEY COLONY BEACH
FL
NOAA Chart: 11449 Latitude: 24° 43.1' N ( 24.71830)
USGS Quad: MARATHON Longitude: 81° 1.0' W ( -81.01670)
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.