U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 8723393 PUBLICATION DATE: 12/12/2003
Name: ELLIOTT KEY (OUTSIDE)
FL
NOAA Chart: 11465 Latitude: 25° 28.6' N ( 25.47670)
USGS Quad: ELLIOTT KEY Longitude: 80° 10.8' W ( -80.18000)
To reach the tidal bench marks by boat from the marina at Convoy Point, 14 km (9
mi) east of Homestead, proceed east across Biscayne Bay for 13.8 km (8.6 statute
mi) to Elliott Key Harbor, then proceed north by vehicle on Elliott Key for 3.2
km (2.0 mi) to a road leading east, then turn right and proceed 0.3 km (0.2 mi)
east on the road to a private residence on the east side of the Key. The bench
marks are located near the second house south of Sands Cut. The tide gage and
staff were located on the pier east of the house.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: NO 2 1974
DESIGNATION: 872 3393 TIDAL 2
MONUMENTATION: Tidal Station disk VM#: 5832
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 25° 28.6' N ( 25.47670) LONGITUDE: 80° 10.8' W ( -80.18000)
The primary bench mark is a disk set in a concrete monument near the south
corner of the house, inside the west outside corner of a rock wall, 11.70 m
(38.4 ft) ENE of bench mark NO 4 1974, 1.55 m (5.1 ft) NE of the north corner of
an opening in the wall, and 0.15 m (0.5 ft) above ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 8723393 PUBLICATION DATE: 12/12/2003
Name: ELLIOTT KEY (OUTSIDE)
FL
NOAA Chart: 11465 Latitude: 25° 28.6' N ( 25.47670)
USGS Quad: ELLIOTT KEY Longitude: 80° 10.8' W ( -80.18000)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 3 1974
DESIGNATION: 872 3393 TIDAL 3
MONUMENTATION: Tidal Station disk VM#: 5833
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 25° 28.6' N ( 25.47670) LONGITUDE: 80° 10.8' W ( -80.18000)
The bench mark is a disk set in a concrete monument near the west corner of the
house, at the inside corner of the south outside corner of the rock wall, 9.08 m
(29.8 ft) NW of bench mark NO 2 1974, and 0.06 m (0.2 ft) above ground level.
BENCH MARK STAMPING: NO 4 1974
DESIGNATION: 872 3393 TIDAL 4
MONUMENTATION: Tidal Station disk VM#: 5834
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Rock and concrete OPUS PID:
LATITUDE: 25° 28.6' N ( 25.47670) LONGITUDE: 80° 10.8' W ( -80.18000)
The bench mark is a disk set in a mass of rock and concrete at the NW end of the
outside rock wall, 14.39 m (47.2 ft) south of the west corner of the house,
12.80 m (42.0 ft) WSW of the south corner of the house, 12 m (40 ft) SSW of
bench mark NO 3 1974, 0.46 m (1.5 ft) NNW of a palm tree, 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 5
Station ID: 8723393 PUBLICATION DATE: 12/12/2003
Name: ELLIOTT KEY (OUTSIDE)
FL
NOAA Chart: 11465 Latitude: 25° 28.6' N ( 25.47670)
USGS Quad: ELLIOTT KEY Longitude: 80° 10.8' W ( -80.18000)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 5 1974
DESIGNATION: 872 3393 TIDAL 5
MONUMENTATION: Tidal Station disk VM#: 5835
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Mass of concrete OPUS PID:
LATITUDE: 25° 28.6' N ( 25.47670) LONGITUDE: 80° 10.8' W ( -80.18000)
The bench mark is a disk set in a mass of concrete at the west corner of the
west side of an opening in the rock wall along the extended line of the SE wall
of the house, 11.67 m (38.3 ft) SSE of bench mark NO 3 1974, 7.47 m (24.5 ft)
east of bench mark NO 4 1974, 5.70 m (18.7 ft) SW of bench mark NO 2 1974, 0.61
m (2.0 ft) SW of the west corner of the wall, 0.18 m (0.6 ft) NW of the wall,
and 0.06 m (0.2 ft) below ground level.
BENCH MARK STAMPING: 3393 F 1984
DESIGNATION: 872 3393 F TIDAL
MONUMENTATION: Tidal Station disk VM#: 5836
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete and rock OPUS PID:
LATITUDE: 25° 28.6' N ( 25.47670) LONGITUDE: 80° 10.8' W ( -80.18000)
The bench mark is a disk set in concrete on top of coral rock, 17.22 m (56.5 ft)
SSE of the south corner of a small building west of the house, 15.30 m (50.2 ft)
SW of bench mark NO 5 1974, 11 m (35 ft) NW of the edge of the rocks at the
shoreline, 12.41 m (40.7 ft) south of bench mark NO 4 1974, and 0.15 m (0.5 ft)
above the rock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 8723393 PUBLICATION DATE: 12/12/2003
Name: ELLIOTT KEY (OUTSIDE)
FL
NOAA Chart: 11465 Latitude: 25° 28.6' N ( 25.47670)
USGS Quad: ELLIOTT KEY Longitude: 80° 10.8' W ( -80.18000)
T I D A L D A T U M S
Tidal datums at ELLIOTT KEY (OUTSIDE) based on:
LENGTH OF SERIES: 1 MONTH
TIME PERIOD: July 1974 - July 1974
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8723170 MIAMI BEACH (CITY PIER)
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 0.770
MEAN HIGH WATER MHW = 0.757
MEAN TIDE LEVEL MTL = 0.414
MEAN SEA LEVEL MSL = 0.410
MEAN LOW WATER MLW = 0.071
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 2 1974 1.213 0.456
NO 3 1974 1.748 0.991
NO 4 1974 1.498 0.741
NO 5 1974 1.016 0.259
3393 F 1984 0.801 0.044
Foot Notes:
Bench mark 3393 F 1984 is based on one differential leveling connection and does
not meet the quality control standards of the NOS. Therefore, caution should be
used when deriving elevations for this mark.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 8723393 PUBLICATION DATE: 12/12/2003
Name: ELLIOTT KEY (OUTSIDE)
FL
NOAA Chart: 11465 Latitude: 25° 28.6' N ( 25.47670)
USGS Quad: ELLIOTT KEY Longitude: 80° 10.8' W ( -80.18000)
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.