U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 8724932 PUBLICATION DATE: 07/15/2004
Name: INDIAN KEY
FL
NOAA Chart: 11429 Latitude: 25° 48.6' N ( 25.81000)
USGS Quad: EVERGLADES CITY Longitude: 81° 27.9' W ( -81.46500)
To reach the tidal bench marks from the mouth of the Barron River in Chokoloskee
Bay, proceed by boat SW along the marked channel for 7.7 km (4.8 mi) to channel
light #4, then SW another 274 m (900 ft) to Indian key. The bench marks are
located near the north end of Indian Key. The tide gage and staff were located
offshore of the NW end of the Key.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 4932 A 1978
DESIGNATION: 872 4932 A TIDAL
MONUMENTATION: Tidal Station disk VM#: 9701
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Unspecified deep rod OPUS PID:
LATITUDE: 25° 48.6' N ( 25.81000) LONGITUDE: 81° 27.9' W ( -81.46500)
The primary bench mark is a disk crimped to an unspecified steel rod, located on
the NE end of the Key in the grassy Campground area, 52 m (170 ft) NNE of the
treeline, 16 m (54 ft) SE of the west shoreline, 11 m (35 ft) west of the east
shoreline, and 1.77 m (5.8 ft) west of the campground registration sign. The
bench mark is crimped to an unspecified steel rod driven 7 m (24 ft) to refusal,
and encased in a 4-inch PVC pipe projecting 0.06 m (0.2 ft) above ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 8724932 PUBLICATION DATE: 07/15/2004
Name: INDIAN KEY
FL
NOAA Chart: 11429 Latitude: 25° 48.6' N ( 25.81000)
USGS Quad: EVERGLADES CITY Longitude: 81° 27.9' W ( -81.46500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: INDIAN KEY 1928
DESIGNATION: INDIAN KEY
MONUMENTATION: Triangulation Station disk VM#: 9700
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: AC4512
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 25° 48.6' N ( 25.81000) LONGITUDE: 81° 27.8' W ( -81.46330)
The bench mark is a disk set in a concrete-filled tile at the high point of a
shell mound approximately 152 m (500 ft) south of the NE point of the Key, 13 m
(42 ft) WNW of Bench Mark 4932 C 1978, 2 m (7 ft) east of a small tree, 1 m (3
ft) west of a 0.15 m (0.5 ft) diameter tree, and 0.30 m (1.0 ft) south of a
metal witness post.
BENCH MARK STAMPING: 4932 B 1978
DESIGNATION: 872 4932 B TIDAL
MONUMENTATION: Tidal Station disk VM#: 9702
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Unspecified deep rod OPUS PID:
LATITUDE: 25° 48.6' N ( 25.81000) LONGITUDE: 81° 27.9' W ( -81.46500)
The bench mark is a disk crimped to an unspecified steel rod, located on the NE
end of the Key in the grassy campground area, 31.03 m (101.8 ft) SSW of Bench
Mark 4932 A 1978, 21 m (68 ft) NE of the treeline, 16 m (53 ft) ESE of the west
shoreline, 14 m (47 ft) west of the east shoreline, and 1 m (2 ft) NE of a metal
witness post. The bench mark is crimped to an unspecified steel rod driven 7 m
(24 ft) to refusal, and encased in a 4-inch PVC pipe projecting 0.15 m (0.5 ft)
above ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 8724932 PUBLICATION DATE: 07/15/2004
Name: INDIAN KEY
FL
NOAA Chart: 11429 Latitude: 25° 48.6' N ( 25.81000)
USGS Quad: EVERGLADES CITY Longitude: 81° 27.9' W ( -81.46500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 4932 C 1978
DESIGNATION: 872 4932 C TIDAL
MONUMENTATION: Tidal Station disk VM#: 9703
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 25° 48.6' N ( 25.81000) LONGITUDE: 81° 27.9' W ( -81.46500)
The bench mark is a disk set in a 0.30 m (1.0 ft) diameter concrete monument on
the east side of the Key, near the high point of a shell mound approximately 152
m (500 ft) south of the NE point of the Key, 24 m (80 ft) south of Bench Mark NO
2, 10 m (32 ft) west of the approximate shoreline, 1.98 m (6.5 ft) east of a
0.30 m (1.0 ft) diameter mangrove tree, 0.24 m (0.8 ft) east of a metal witness
post, and at ground level.
BENCH MARK STAMPING: NO 2
DESIGNATION: 872 4932 TIDAL 2
MONUMENTATION: Reference Mark disk VM#: 9704
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 25° 48.6' N ( 25.81000) LONGITUDE: 99° 27.9' W ( -99.46500)
The bench mark is a disk set in a concrete-filled tile on the east side of
Indian Key approximately 122 m (400 ft) south of the NE point of the Key, 9 m
(28 ft) WSW of the shoreline, 7 m (24 ft) south of a tree with three trunks, 4 m
(12 ft) NE of the treeline, and 0.30 m (1.0 ft) NE of a metal witness post.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 8724932 PUBLICATION DATE: 07/15/2004
Name: INDIAN KEY
FL
NOAA Chart: 11429 Latitude: 25° 48.6' N ( 25.81000)
USGS Quad: EVERGLADES CITY Longitude: 81° 27.9' W ( -81.46500)
T I D A L D A T U M S
Tidal datums at INDIAN KEY based on:
LENGTH OF SERIES: 2 MONTHS
TIME PERIOD: June 1978 - July 1978
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8724919 CHOKOLOSKEE
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 1.276
MEAN HIGH WATER MHW = 1.197
MEAN SEA LEVEL MSL = 0.712
MEAN TIDE LEVEL MTL = 0.699
MEAN LOW WATER MLW = 0.200
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
4932 A 1978 2.133 0.936
INDIAN KEY 1928 3.176 1.979
4932 B 1978 2.296 1.099
4932 C 1978 3.225 2.028
NO 2 2.265 1.068
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 8724932 PUBLICATION DATE: 07/15/2004
Name: INDIAN KEY
FL
NOAA Chart: 11429 Latitude: 25° 48.6' N ( 25.81000)
USGS Quad: EVERGLADES CITY Longitude: 81° 27.9' W ( -81.46500)
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.