U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 6
Station ID: 8723693 PUBLICATION DATE: 02/13/2004
Name: GAGE A, POINT CHARLES, KEY LARGO
FL
NOAA Chart: 11463 Latitude: 25° 4.6' N ( 25.07670)
USGS Quad: ROCK HARBOR Longitude: 80° 27.3' W ( -80.45500)
To reach the tidal bench marks from the post office in Key Largo, proceed south
on U.S. Highway 1 for 2.3 km (1.4 mi) to Grand Street, the turn left and proceed
SE on Grand Street for 0.5 km (0.3 mi) to the residence at 1128 Grand Street.
The bench marks are located at the residence and near Anthony's of Key Largo on
U.S. Highway 1. The tide gage and staff were located at the SE end of the
concrete sea wall at 1128 Grand Street.
T I D A L B E N C H M A R K S
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 6
Station ID: 8723693 PUBLICATION DATE: 02/13/2004
Name: GAGE A, POINT CHARLES, KEY LARGO
FL
NOAA Chart: 11463 Latitude: 25° 4.6' N ( 25.07670)
USGS Quad: ROCK HARBOR Longitude: 80° 27.3' W ( -80.45500)
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: X 275 1966
DESIGNATION: X 275
MONUMENTATION: Bench Mark disk VM#: 5975
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: AC1009
SETTING CLASSIFICATION: Concrete wall of building OPUS PID:
LATITUDE: 25° 4.8' N ( 25.08000) LONGITUDE: 80° 27.4' W ( -80.45670)
The primary bench mark is a disk set flush vertically in the NW face of the
concrete block office building for the Lavicka Real Estate Company, 91 m (300
ft) SW of Anthony's of Key Largo, 24.69 m (81.0 ft) SE of the centerline of U.S.
Highway 1, 5.58 m (18.3 ft) NE of the west corner of the building, and 0.27 m
(0.9 ft) above ground level.
BENCH MARK STAMPING: NO 1 1975
DESIGNATION: 872 3693 TIDAL 1
MONUMENTATION: Tidal Station disk VM#: 5976
AGENCY: National Ocean Survey (NOS) IDB PID#: AC3357
SETTING CLASSIFICATION: Concrete patio OPUS PID:
LATITUDE: 25° 4.6' N ( 25.07670) LONGITUDE: 80° 27.3' W ( -80.45500)
The bench mark is a disk located at the last house on the SW side of Grand
Street, set flush in a 2 m x 5 m (6 ft x 15 ft) patio at the east corner of the
residence at 1128 Grand Street, and 19.96 m (65.5 ft) NW of the sea wall running
NW to SE.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 6
Station ID: 8723693 PUBLICATION DATE: 02/13/2004
Name: GAGE A, POINT CHARLES, KEY LARGO
FL
NOAA Chart: 11463 Latitude: 25° 4.6' N ( 25.07670)
USGS Quad: ROCK HARBOR Longitude: 80° 27.3' W ( -80.45500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 2 1975
DESIGNATION: 872 3693 TIDAL 2
MONUMENTATION: Tidal Station disk VM#: 5977
AGENCY: National Ocean Survey (NOS) IDB PID#: AC3356
SETTING CLASSIFICATION: Concrete sea wall sidewalk OPUS PID:
LATITUDE: 25° 4.6' N ( 25.07670) LONGITUDE: 80° 27.3' W ( -80.45500)
The bench mark is a disk set flush in a concrete sea wall sidewalk running SE to
NW, 11.13 m (36.5 ft) west of the south corner of the residence at 1128 Grand
Street, 10 m (32 ft) SSE of the west corner of the residence, and 0.58 m (1.9
ft) below ground level.
BENCH MARK STAMPING: NO 3 1975
DESIGNATION: 872 3693 TIDAL 3
MONUMENTATION: Tidal Station disk VM#: 5978
AGENCY: National Ocean Survey (NOS) IDB PID#: AC3358
SETTING CLASSIFICATION: Concrete patio OPUS PID:
LATITUDE: 25° 4.6' N ( 25.07670) LONGITUDE: 80° 27.3' W ( -80.45500)
The bench mark is a disk set flush in a 1 m x 2 m (3 ft x 6 ft) concrete patio
at the NW entrance of the residence at 1128 Grand Street, 12 m (38 ft) NE of the
sea wall running SE to NW, 6 m (19 ft) NE of the west corner of the residence,
and 4.39 m (14.4 ft) SW of the north corner of the residence.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 6
Station ID: 8723693 PUBLICATION DATE: 02/13/2004
Name: GAGE A, POINT CHARLES, KEY LARGO
FL
NOAA Chart: 11463 Latitude: 25° 4.6' N ( 25.07670)
USGS Quad: ROCK HARBOR Longitude: 80° 27.3' W ( -80.45500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 3693 E 1982 BSM
DESIGNATION: 872 3693 E TIDAL
MONUMENTATION: Tidal Station disk VM#: 5979
AGENCY: Florida Department of Natural Resources
(FLDNR) IDB PID#: AC3355
SETTING CLASSIFICATION: Concrete loading platform OPUS PID:
LATITUDE: 25° 4.9' N ( 25.08170) LONGITUDE: 80° 27.3' W ( -80.45500)
The bench mark is a disk set flush in a concrete loading platform behind
Anthony's of Key Largo, 60 m (197 ft) NE of the centerline of Grand Street,
18.93 m (62.1 ft) NW of the centerline of the northbound lane of U.S. Highway 1,
8.44 m (27.7 ft) south of the NE corner of the restaurant, and 0.30 m (1 ft)
above ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 6
Station ID: 8723693 PUBLICATION DATE: 02/13/2004
Name: GAGE A, POINT CHARLES, KEY LARGO
FL
NOAA Chart: 11463 Latitude: 25° 4.6' N ( 25.07670)
USGS Quad: ROCK HARBOR Longitude: 80° 27.3' W ( -80.45500)
T I D A L D A T U M S
Tidal datums at GAGE A, POINT CHARLES, KEY LARGO based on:
LENGTH OF SERIES: 3 MONTHS
TIME PERIOD: May 1975 - July 1975
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8723747 TAVERNIER HAWK CHANNEL
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 0.672
MEAN HIGH WATER MHW = 0.642
North American Vertical Datum NAVD88 = 0.588
MEAN SEA LEVEL MSL = 0.342
MEAN TIDE LEVEL MTL = 0.341
MEAN LOW WATER MLW = 0.040
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
X 275 1966 4.074 3.432
NO 1 1975 1.641 0.999
NO 2 1975 0.924 0.282
NO 3 1975 1.676 1.034
3693 E 1982 BSM 4.368 3.726
Foot Notes:
Bench mark 3693 E 1982 BSM 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 6 of 6
Station ID: 8723693 PUBLICATION DATE: 02/13/2004
Name: GAGE A, POINT CHARLES, KEY LARGO
FL
NOAA Chart: 11463 Latitude: 25° 4.6' N ( 25.07670)
USGS Quad: ROCK HARBOR Longitude: 80° 27.3' W ( -80.45500)
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.