U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 7
Station ID: 8724334 PUBLICATION DATE: 05/28/2004
Name: TARPON CREEK, SUGARLOAF KEY
FL
NOAA Chart: 11434 Latitude: 24° 37.8' N ( 24.63000)
USGS Quad: SUGARLOAF KEY Longitude: 81° 31.0' W ( -81.51670)
To reach the tidal bench marks from the post office at Sugarloaf Shores, proceed
0.2 km (0.1 mi) SW on U.S. Highway 1 to the junction of County Road C939
(Sugarloaf Boulevard), then turn left and proceed south on C939 for 4.3 km (2.7
mi) to a T junction, then proceed NE on old C939 (no longer maintained) for 3.2
km (2.0 mi) to a burned-out bridge at Tarpon Creek. The bench marks are located
along State Road C939. The tide gage and staff were located on the west side of
Tarpon Creek bridge on State Road C939 which has been burned out.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: NO 1 1974
DESIGNATION: 872 4334 TIDAL 1
MONUMENTATION: Tidal Station disk VM#: 6981
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Unspecified rock OPUS PID:
LATITUDE: 24° 37.8' N ( 24.63000) LONGITUDE: 81° 31.0' W ( -81.51670)
The primary bench mark is a disk set in a mass of concrete in rock located near
the NW corner of a burned-out wooden bridge over Tarpon Creek, 3.5 km (2.2 mi)
south of U.S. Highway 1 along State Road C939, 6.86 m (22.5 ft) north of the
center of the wooden bridge, and 3.51 m (11.5 ft) west of the centerline of
State Road C939. NOTE: Mark not recovered in 1980.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 7
Station ID: 8724334 PUBLICATION DATE: 05/28/2004
Name: TARPON CREEK, SUGARLOAF KEY
FL
NOAA Chart: 11434 Latitude: 24° 37.8' N ( 24.63000)
USGS Quad: SUGARLOAF KEY Longitude: 81° 31.0' W ( -81.51670)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 2 1974
DESIGNATION: 872 4334 TIDAL 2
MONUMENTATION: Tidal Station disk VM#: 6982
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete post OPUS PID:
LATITUDE: 24° 37.8' N ( 24.63000) LONGITUDE: 81° 31.0' W ( -81.51670)
The bench mark is a disk set in concrete, 2.2 miles (3.5 km) south of U.S.
Highway 1 along State Road C939, 66.87 m (219.4 ft) south of the centerline of
the wooden bridge, 6.10 m (20.0 ft) east of State Road C939, and 0.06 m (0.2
ft) above ground level. NOTE: Mark not recovered in 1982.
BENCH MARK STAMPING: NO 3 1974
DESIGNATION: 872 4334 TIDAL 3
MONUMENTATION: Tidal Station disk VM#: 6983
AGENCY: National Ocean Survey (NOS) IDB PID#: AA0914
SETTING CLASSIFICATION: Concrete post OPUS PID:
LATITUDE: 24° 37.8' N ( 24.63000) LONGITUDE: 81° 31.0' W ( -81.51670)
The bench mark is a disk set in top of a concrete post, 52.27 m (179.5 ft) south
of the north edge of the end of the pavement at the burned-out bridge over the
creek, 14 m (47 ft) WSW of bench mark NO 4 1974, and 6.07 m (19.9 ft) west of
the centerline of State Road C939, 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 7
Station ID: 8724334 PUBLICATION DATE: 05/28/2004
Name: TARPON CREEK, SUGARLOAF KEY
FL
NOAA Chart: 11434 Latitude: 24° 37.8' N ( 24.63000)
USGS Quad: SUGARLOAF KEY Longitude: 81° 31.0' W ( -81.51670)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 4 1974
DESIGNATION: 872 4334 TIDAL 4
MONUMENTATION: Tidal Station disk VM#: 6984
AGENCY: National Ocean Survey (NOS) IDB PID#: AA0912
SETTING CLASSIFICATION: Concrete post OPUS PID:
LATITUDE: 24° 37.8' N ( 24.63000) LONGITUDE: 81° 31.0' W ( -81.51670)
The bench mark is a disk set in top of a concrete post, 55 m (181 ft) south of
the edge of Tarpon Creek, 14 m (47 ft) ENE of tidal bench mark NO 3 1974, 6.40 m
(21.0 ft) east of the centerline of the road, and 0.06 m (0.2 ft) above ground
level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 7
Station ID: 8724334 PUBLICATION DATE: 05/28/2004
Name: TARPON CREEK, SUGARLOAF KEY
FL
NOAA Chart: 11434 Latitude: 24° 37.8' N ( 24.63000)
USGS Quad: SUGARLOAF KEY Longitude: 81° 31.0' W ( -81.51670)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: X 272 1966
DESIGNATION: X 272
MONUMENTATION: Bench Mark disk VM#: 6985
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: AA0150
SETTING CLASSIFICATION: Concrete post OPUS PID:
LATITUDE: 24° 37.9' N ( 24.63170) LONGITUDE: 81° 30.9' W ( -81.51500)
The bench mark is a disk set in top of a concrete post, 3.5 km (2.2 mi) south of
U.S. Highway 1 along State Road C939, 136 m (447 ft) north of the NE corner of a
burned-out bridge over Tarpon Creek, 6 m (19 ft) east of the centerline of State
Road C939, 1 m (2 ft) north of a metal witness post, and 0.20 m (0.6 ft) above
the level of the ground.
BENCH MARK STAMPING: 4334 G 1982
DESIGNATION: 872 4334 G TIDAL
MONUMENTATION: Tidal Station disk VM#: 6987
AGENCY: National Ocean Survey (NOS) IDB PID#: AA0913
SETTING CLASSIFICATION: Concrete post OPUS PID:
LATITUDE: 24° 37.8' N ( 24.63000) LONGITUDE: 81° 30.9' W ( -81.51500)
The bench mark is a disk set in top of a concrete post, 5.03 m (16.5 ft) south
of a creek, 3.3 m (10.8 ft) east of the centerline of the State Road C939, 2.74
m (8.99 ft) south of the north end of the pavement, 1.25 m (4.1 ft) NE of the
easternmost boulder of three boulders blocking the road, 0.40 m (1.3 ft) east of
a 0.15 m (0.5 ft) diameter wood post, and 0.06 m (0.2 ft) below ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 7
Station ID: 8724334 PUBLICATION DATE: 05/28/2004
Name: TARPON CREEK, SUGARLOAF KEY
FL
NOAA Chart: 11434 Latitude: 24° 37.8' N ( 24.63000)
USGS Quad: SUGARLOAF KEY Longitude: 81° 31.0' W ( -81.51670)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: GONDOLPHO AZ MARK 1935
DESIGNATION: GONDOLPHO AZ MK
MONUMENTATION: Reference Mark disk VM#: 6988
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: AA0152
SETTING CLASSIFICATION: Concrete post OPUS PID:
LATITUDE: 24° 37.8' N ( 24.63000) LONGITUDE: 81° 30.9' W ( -81.51500)
The bench mark is a disk set in a concrete post at the SE end of the Key, 3.9 km
(2.4 mi) south of the Florida East Coast Railway station at Pirates Cove, 0.5 km
(0.3 mi) south of highway bridge No. 20 over Gondolpho Creek, 0.3 km (0.2 mi)
south of State Road C939, and 38 m (125 ft) SW of an old shack.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 7
Station ID: 8724334 PUBLICATION DATE: 05/28/2004
Name: TARPON CREEK, SUGARLOAF KEY
FL
NOAA Chart: 11434 Latitude: 24° 37.8' N ( 24.63000)
USGS Quad: SUGARLOAF KEY Longitude: 81° 31.0' W ( -81.51670)
T I D A L D A T U M S
Tidal datums at TARPON CREEK, SUGARLOAF KEY based on:
LENGTH OF SERIES: 1 MONTH
TIME PERIOD: April 1974 - April 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:
North American Vertical Datum NAVD88 = 0.302
MEAN HIGHER HIGH WATER MHHW = 0.190
MEAN HIGH WATER MHW = 0.162
MEAN TIDE LEVEL MTL = 0.093
MEAN SEA LEVEL MSL = 0.091
MEAN LOW WATER MLW = 0.024
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 1974 2.882 2.720
NO 2 1974 0.602 0.440
NO 3 1974 0.407 0.245
NO 4 1974 0.482 0.320
X 272 1966 0.380 0.218
4334 G 1982 2.605 2.443
GONDOLPHO AZ MARK 1935 0.530 0.368
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 7 of 7
Station ID: 8724334 PUBLICATION DATE: 05/28/2004
Name: TARPON CREEK, SUGARLOAF KEY
FL
NOAA Chart: 11434 Latitude: 24° 37.8' N ( 24.63000)
USGS Quad: SUGARLOAF KEY Longitude: 81° 31.0' W ( -81.51670)
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.