U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 6
Station ID: 8723518 PUBLICATION DATE: 05/12/2004
Name: WEDNESDAY POINT, KEY LARGO
FL
NOAA Chart: 11463 Latitude: 25° 18.6' N ( 25.31000)
USGS Quad: CARD SOUND Longitude: 80° 17.9' W ( -80.29830)
To reach the tidal bench marks from Barnes Point at the east end of the toll
bridge dividing Little Card Sound and Barnes Sound, proceed east on State Road
905A for 6.1 km (3.8 mi) to State Road 905, then turn left and proceed NNE on
State Road 905 for 3.0 km (1.9 mi), then bear left onto the road which leads to
Key Largo Anglers Club and Card Sound. The bench marks are located on the club
property near the docks. The tide gage and staff were located on a wooden dock
at the south tip of the coral fill breakwater.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: NO 1 1971
DESIGNATION: 872 3518 TIDAL 1
MONUMENTATION: Tidal Station disk VM#: 5892
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: AC3324
SETTING CLASSIFICATION: Concrete base OPUS PID:
LATITUDE: 25° 18.6' N ( 25.31000) LONGITUDE: 80° 18.0' W ( -80.30000)
The primary bench mark is a disk set flush in the SW corner of a 1.58 m (5.2 ft)
square concrete base for a privately maintained navigation light, located on the
south tip of a coral fill breakwater, 5 m (18 ft) west of the waters edge, 5 m
(16 ft) east of the waters edge, 4.05 m (13.3 ft) north of the waters edge, and
0.3 m (1 ft) above the level of the road which runs the length of the
breakwater.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 6
Station ID: 8723518 PUBLICATION DATE: 05/12/2004
Name: WEDNESDAY POINT, KEY LARGO
FL
NOAA Chart: 11463 Latitude: 25° 18.6' N ( 25.31000)
USGS Quad: CARD SOUND Longitude: 80° 17.9' W ( -80.29830)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 3518 E 1982 BSM
DESIGNATION: 872 3518 E TIDAL FLDNR
MONUMENTATION: Tidal Station disk VM#: 5889
AGENCY: Florida Department of Natural Resources
(FLDNR) IDB PID#: AC3321
SETTING CLASSIFICATION: Concrete bulkhead OPUS PID:
LATITUDE: 25° 18.7' N ( 25.31170) LONGITUDE: 80° 17.9' W ( -80.29830)
The bench mark is a disk set flush in a concrete bulkhead, 17.28 m (56.7 ft)
north of a 1.22 m (4.0 ft) diameter banyan tree, 9.11 m (29.9 ft) SW of the SW
corner of a storage shed, 8.69 m (28.5 ft) east of a concrete water valve box,
0.70 m (2.3 ft) south of the edge of the sea wall, and at ground level.
BENCH MARK STAMPING: 3518 F 1982 BSM
DESIGNATION: 872 3518 F TIDAL FLDNR
MONUMENTATION: Tidal Station disk VM#: 5890
AGENCY: Florida Department of Natural Resources
(FLDNR) IDB PID#: AC3322
SETTING CLASSIFICATION: Concrete bulkhead OPUS PID:
LATITUDE: 25° 18.7' N ( 25.31170) LONGITUDE: 80° 17.9' W ( -80.29830)
The bench mark is a disk set flush in a concrete bulkhead, 10.03 m (32.9 ft)
north of the NW corner of the storage shed, 7.74 m (25.4 ft) SW of the NW corner
of the dockmaster office, 0.67 m (2.2 ft) east of the edge of the sea wall, and
at ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 6
Station ID: 8723518 PUBLICATION DATE: 05/12/2004
Name: WEDNESDAY POINT, KEY LARGO
FL
NOAA Chart: 11463 Latitude: 25° 18.6' N ( 25.31000)
USGS Quad: CARD SOUND Longitude: 80° 17.9' W ( -80.29830)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 3518 G 1982 BSM
DESIGNATION: 872 3518 G TIDAL FLDNR
MONUMENTATION: Tidal Station disk VM#: 5891
AGENCY: Florida Department of Natural Resources
(FLDNR) IDB PID#: AC3323
SETTING CLASSIFICATION: Concrete bulkhead OPUS PID:
LATITUDE: 25° 18.7' N ( 25.31170) LONGITUDE: 80° 17.9' W ( -80.29830)
The bench mark is a disk set flush in a concrete bulkhead, 8.72 m (28.6 ft)
north of a 0.37 m (1.2 ft) diameter seagrape tree, 2.71 m (8.9 ft) east of the
west edge of the pier, 0.91 m (3.0 ft) west of the NW corner of the store, 0.55
m (1.8 ft) south of the edge of the sea wall, and at ground level.
BENCH MARK STAMPING: NO 2 1971
DESIGNATION: 872 3518 TIDAL 2
MONUMENTATION: Tidal Station disk VM#: 5893
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Concrete head wall OPUS PID:
LATITUDE: 25° 18.6' N ( 25.31000) LONGITUDE: 80° 17.9' W ( -80.29830)
The bench mark is a disk set flush in the northern concrete head wall for the
westernmost of six culverts which pass under the breakwater, 8 m (58 ft) east of
the only bend in the breakwater, 6 m (20 ft) north of the NE corner of a pier, 4
m (12 ft) north of the centerline of the roadway, 1.01 m (3.3 ft) west of the
east edge of the head wall, 0.12 m (0.4 ft) south of the north edge of the head
wall, and 1 m (3 ft) below road level. NOTE: The bench mark is currently
inaccessible as the culvert head wall is now covered with boulders cemented
together.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 6
Station ID: 8723518 PUBLICATION DATE: 05/12/2004
Name: WEDNESDAY POINT, KEY LARGO
FL
NOAA Chart: 11463 Latitude: 25° 18.6' N ( 25.31000)
USGS Quad: CARD SOUND Longitude: 80° 17.9' W ( -80.29830)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: P 275 1966
DESIGNATION: P 275
MONUMENTATION: Bench Mark disk VM#: 15838
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: AC1056
SETTING CLASSIFICATION: Rock outcrop OPUS PID:
LATITUDE: 25° 18.5' N ( 25.30830) LONGITUDE: 80° 17.6' W ( -80.29330)
The bench mark is a disk set in a large flat rock outcrop, 10.82 m (35.5 ft) SW
of the centerline of the drive to the clubhouse, 22.86 m (75.0 ft) NW of the
centerline of State Highway 905, and 9.14 m (30.0 ft) west of the west corner of
a stone post at the SW end of a metal gate across the drive. NOTE: Mark not
found in 1988 by US Power Squadron.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 6
Station ID: 8723518 PUBLICATION DATE: 05/12/2004
Name: WEDNESDAY POINT, KEY LARGO
FL
NOAA Chart: 11463 Latitude: 25° 18.6' N ( 25.31000)
USGS Quad: CARD SOUND Longitude: 80° 17.9' W ( -80.29830)
T I D A L D A T U M S
Tidal datums at WEDNESDAY POINT, KEY LARGO based on:
LENGTH OF SERIES: 4 MONTHS
TIME PERIOD: November 1971 - February 1972
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:
North American Vertical Datum NAVD88 = 0.382
MEAN HIGHER HIGH WATER MHHW = 0.263
MEAN HIGH WATER MHW = 0.252
MEAN TIDE LEVEL MTL = 0.138
MEAN SEA LEVEL MSL = 0.130
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 1971 2.330 2.078
3518 E 1982 BSM 0.814 0.562
3518 F 1982 BSM 1.283 1.031
3518 G 1982 BSM 1.352 1.100
NO 2 1971 0.717 0.465
P 275 1966 1.490 1.238
Foot Notes:
Bench marks 3518 E 1982 BSM, 3518 F 1982 BSM, 3518 G 1982 BSM and P 275 1966 are
based on one differential leveling connection and do not meet the quality
control standards of the NOS. Therefore, caution should be used when deriving
elevations for these marks.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 6
Station ID: 8723518 PUBLICATION DATE: 05/12/2004
Name: WEDNESDAY POINT, KEY LARGO
FL
NOAA Chart: 11463 Latitude: 25° 18.6' N ( 25.31000)
USGS Quad: CARD SOUND Longitude: 80° 17.9' W ( -80.29830)
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.