U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 6
Station ID: 8724098 PUBLICATION DATE: 02/26/2004
Name: COCOANUT KEY
FL
NOAA Chart: 11442 Latitude: 24° 44.7' N ( 24.74500)
USGS Quad: SEVENMILE BRIDGE Longitude: 81° 14.2' W ( -81.23670)
To reach the tidal bench marks by boat from the west end of Seven Mile Bridge on
Little Duck Key, proceed 7.0 km (3.8 nm) north to the NW side of Cocoanut Key.
The bench marks are located on the island of Cocoanut Key. The tide gage and
staff were located on the Government Wildlife Refuge pier on the west side of
the island.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: NO 1 1935
DESIGNATION: 872 4098 TIDAL 1
MONUMENTATION: Tidal Station disk VM#: 6337
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Concrete pillar OPUS PID:
LATITUDE: 24° 44.7' N ( 24.74500) LONGITUDE: 81° 14.2' W ( -81.23670)
The primary bench mark is a disk set in the top of a 0.24 m (0.8 ft) square
concrete pillar, 18 m (58 ft) ESE of the edge of the WNW mangrove roots at the
water line, 12.95 m (42.5 ft) WNW of reference mark COCOANUT KEY 3 RM 2, and
0.30 m (1.0 ft) east of a witness post.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 6
Station ID: 8724098 PUBLICATION DATE: 02/26/2004
Name: COCOANUT KEY
FL
NOAA Chart: 11442 Latitude: 24° 44.7' N ( 24.74500)
USGS Quad: SEVENMILE BRIDGE Longitude: 81° 14.2' W ( -81.23670)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1 A 1974
DESIGNATION: 872 4098 1 A
MONUMENTATION: Tidal Station disk VM#: 6338
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID:
LATITUDE: 24° 44.7' N ( 24.74500) LONGITUDE: 81° 14.2' W ( -81.23670)
The bench mark is a disk located 25.60 m (84.0 ft) north of bench mark NO 1
1935, 11.89 m (39.0 ft) east of the outer mangrove edge, 11 m (35 ft) ESE of the
WNW edge of the mangrove roots at the water line, and 0.40 m (1.3 ft) west of a
witness post. The bench mark is set 3 cm (0.1 ft) above ground level, crimped
to the top of a copper-clad steel rod driven to refusal, encased in a PVC pipe
and concrete kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 6
Station ID: 8724098 PUBLICATION DATE: 02/26/2004
Name: COCOANUT KEY
FL
NOAA Chart: 11442 Latitude: 24° 44.7' N ( 24.74500)
USGS Quad: SEVENMILE BRIDGE Longitude: 81° 14.2' W ( -81.23670)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: COCOANUT KEY 3 1934
DESIGNATION: COCOANUT KEY 3
MONUMENTATION: Triangulation Station disk VM#: 6339
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: AA1496
SETTING CLASSIFICATION: Concrete pillar OPUS PID:
LATITUDE: 24° 44.7' N ( 24.74500) LONGITUDE: 81° 14.1' W ( -81.23500)
The bench mark is a disk set in the top of a concrete monument, 39.99 m (131.2
ft) east of the clearing in grass and low brush, and 0.21 m (0.7 ft) NW of the
witness post, and 0.15 m (0.5 ft) above ground level.
BENCH MARK STAMPING: COCOANUT KEY 3 RM 1
DESIGNATION: 872 4098 COCOANUT RM 1
MONUMENTATION: Reference Mark disk VM#: 6340
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: AE4387
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 24° 44.7' N ( 24.74500) LONGITUDE: 81° 14.2' W ( -81.23670)
The bench mark is a disk set in the top of a concrete monument, 23.56 m (77.3
ft) SSE of triangulation mark COCOANUT KEY 3 1934, 0.18 m (0.6 ft) NNW of a
witness post, and 0.15 m (0.5 ft) above ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 6
Station ID: 8724098 PUBLICATION DATE: 02/26/2004
Name: COCOANUT KEY
FL
NOAA Chart: 11442 Latitude: 24° 44.7' N ( 24.74500)
USGS Quad: SEVENMILE BRIDGE Longitude: 81° 14.2' W ( -81.23670)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: COCOANUT KEY 3 RM 2
DESIGNATION: 872 4098 COCOANUT RM 2
MONUMENTATION: Reference Mark disk VM#: 6341
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: AE4388
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 24° 44.7' N ( 24.74500) LONGITUDE: 81° 14.2' W ( -81.23670)
The bench mark is a disk set in the top of a concrete monument, 20.06 m (65.8
ft) WSW of triangulation mark COCOANUT KEY 3 1934, 0.18 m (0.6 ft) NE of a
witness post, and 0.21 m (0.7 ft) above ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 6
Station ID: 8724098 PUBLICATION DATE: 02/26/2004
Name: COCOANUT KEY
FL
NOAA Chart: 11442 Latitude: 24° 44.7' N ( 24.74500)
USGS Quad: SEVENMILE BRIDGE Longitude: 81° 14.2' W ( -81.23670)
T I D A L D A T U M S
Tidal datums at COCOANUT KEY based on:
LENGTH OF SERIES: 1 MONTH
TIME PERIOD: June 1974 - June 1974
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8724211 BIG PINE KEY VIADUCT
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 0.360
MEAN HIGH WATER MHW = 0.302
MEAN TIDE LEVEL MTL = 0.196
MEAN SEA LEVEL MSL = 0.189
MEAN LOW WATER MLW = 0.090
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 1935 0.646 0.344
1 A 1974 0.525 0.223
COCOANUT KEY 3 1934 0.493 0.191
COCOANUT KEY 3 RM 1 0.536 0.234
COCOANUT KEY 3 RM 2 0.573 0.271
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 6
Station ID: 8724098 PUBLICATION DATE: 02/26/2004
Name: COCOANUT KEY
FL
NOAA Chart: 11442 Latitude: 24° 44.7' N ( 24.74500)
USGS Quad: SEVENMILE BRIDGE Longitude: 81° 14.2' W ( -81.23670)
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.