U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 8724313 PUBLICATION DATE: 05/28/2004
Name: CUDJOE BAY
FL
NOAA Chart: 11448 Latitude: 24° 39.6' N ( 24.66000)
USGS Quad: SUMMERLAND KEY Longitude: 81° 29.5' W ( -81.49170)
To reach the tidal bench marks from the post office at Summerland Key, proceed
west on U.S. Highway 1 for 4.5 km (2.8 mi) to a private drive leading south,
continue south for 0.3 km (0.2 mi) to a small house on stilts. The bench marks
are located in the vicinity of the dwelling and along U.S. Highway 1. The tide
gage and staff were located south of a small pier at the end of the dirt road
leading to the house on stilts.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: NO 1 1974
DESIGNATION: 872 4313 TIDAL 1
MONUMENTATION: Tidal Station disk VM#: 6935
AGENCY: National Ocean Survey (NOS) IDB PID#: AA0977
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID:
LATITUDE: 24° 39.8' N ( 24.66330) LONGITUDE: 81° 29.5' W ( -81.49170)
The primary bench mark is a disk located near the SE corner of the property,
24.81 m (81.4 ft) east of bench mark NO 2 1974, 21 m (68 ft) north of the
shoreline, and 20.70 m (67.9 ft). The bench mark is set 6 cm (0.2 ft) above the
ground, crimped to the top of a copper-clad rod driven an unspecified depth to
refusal and encased in a concrete kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 8724313 PUBLICATION DATE: 05/28/2004
Name: CUDJOE BAY
FL
NOAA Chart: 11448 Latitude: 24° 39.6' N ( 24.66000)
USGS Quad: SUMMERLAND KEY Longitude: 81° 29.5' W ( -81.49170)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 2 1974
DESIGNATION: 872 4313 TIDAL 2
MONUMENTATION: Tidal Station disk VM#: 6936
AGENCY: National Ocean Survey (NOS) IDB PID#: AA0978
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID:
LATITUDE: 24° 39.8' N ( 24.66330) LONGITUDE: 81° 29.5' W ( -81.49170)
The bench mark is a disk located near the SW corner of Chet Rogers property,
18.71 m (61.4 ft) SW of the SW corner of the house, and 2 m (5 ft) north of the
shoreline. The bench mark is set 0.06 m (0.2 ft) above the ground, crimped to
the top of a copper-clad rod driven an unspecified depth to refusal and encased
in a concrete kickblock.
BENCH MARK STAMPING: 4313 D 1982
DESIGNATION: 872 4313 D TIDAL
MONUMENTATION: Tidal Station disk VM#: 6937
AGENCY: National Ocean Survey (NOS) IDB PID#: AA0976
SETTING CLASSIFICATION: Concrete footing OPUS PID:
LATITUDE: 24° 39.9' N ( 24.66500) LONGITUDE: 81° 29.2' W ( -81.48670)
The bench mark is a disk set in the concrete footing of a power pole along U.S.
Highway 1, 3.94 km (2.45 mi) west of the post office at Summerland Key, 31.30 m
(102.7 ft) east of the centerline of a paved road leading south, 12.95 m (42.5
ft) south of the centerline of U.S. Highway 1, 0.15 m (0.5 ft) NW of the NW
corner of a concrete power pole, and 1 m (2 ft) below highway level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 8724313 PUBLICATION DATE: 05/28/2004
Name: CUDJOE BAY
FL
NOAA Chart: 11448 Latitude: 24° 39.6' N ( 24.66000)
USGS Quad: SUMMERLAND KEY Longitude: 81° 29.5' W ( -81.49170)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: J 272 1966
DESIGNATION: J 272
MONUMENTATION: Bench Mark disk VM#: 6938
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: AA0177
SETTING CLASSIFICATION: Concrete base OPUS PID:
LATITUDE: 24° 39.8' N ( 24.66330) LONGITUDE: 81° 28.9' W ( -81.48170)
The bench mark is a disk set on the top of the west side of a 3 x 2 m (9 x 6 ft)
concrete base for a manhole cover over the water line, 4.5 km (2.8 mi) west of
Summerland Key, 0.8 km (0.5 mi) east of U.S. Highway 1 milepost 22, 6.25 m (20.5
ft) north of the centerline of the highway, 1.07 m (3.5 ft) south of the NW
corner of the base.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 8724313 PUBLICATION DATE: 05/28/2004
Name: CUDJOE BAY
FL
NOAA Chart: 11448 Latitude: 24° 39.6' N ( 24.66000)
USGS Quad: SUMMERLAND KEY Longitude: 81° 29.5' W ( -81.49170)
T I D A L D A T U M S
Tidal datums at CUDJOE BAY based on:
LENGTH OF SERIES: 1 MONTH
TIME PERIOD: October 1974 - October 1974
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8724580 KEY WEST
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 0.482
North American Vertical Datum NAVD88 = 0.460
MEAN HIGH WATER MHW = 0.401
MEAN TIDE LEVEL MTL = 0.225
MEAN SEA LEVEL MSL = 0.221
MEAN LOW WATER MLW = 0.049
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 0.777 0.376
NO 2 1974 0.825 0.424
4313 D 1982 1.303 0.902
J 272 1966 1.664 1.263
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 8724313 PUBLICATION DATE: 05/28/2004
Name: CUDJOE BAY
FL
NOAA Chart: 11448 Latitude: 24° 39.6' N ( 24.66000)
USGS Quad: SUMMERLAND KEY Longitude: 81° 29.5' W ( -81.49170)
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.