U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 4
PUBLICATION DATE: 06/16/1986
Station ID: 8724226 SUPERCEDED DATE: 04/21/2003
Name: BIG PINE KEY, NE SHORE, WEST OF BIG SPANISH CHANNE
FLORIDA
NOAA Chart: 11448 Latitude: 24° 43.7' N
USGS Quad: SUMMERLAND KEY Longitude: 81° 23.2' W
To reach the tidal bench marks from the intersection of U.S. Highway 1 and State
Highway S-940, proceed NW on S-940 for 4.3 miles (6.9 m) to the end of the road.
The bench marks are located at the end of the road and in the vicinity of a
cut. The tide gage and staff were located in the cut.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: NO 1 1974
MONUMENTATION: Survey Disk VM#: 8997
AGENCY: PID:
SETTING CLASSIFICATION: Concrete/Rod Monument
The bench mark is set in concrete atop of a copper-clad rod driven to refusal,
at the intersection of a drainage ditch and the south shore of the cut,
approximately 350 feet (107 m) east and 150 feet (46 m) south of the end of
S-940, 11 feet (3 m) SE of the south shore of the cut, 4 feet (1 m) west of a
drainage ditch, and 0.5 foot (0.2 m) above the ground.
BENCH MARK STAMPING: NO 2 1974
MONUMENTATION: Survey Disk VM#: 8998
AGENCY: PID:
SETTING CLASSIFICATION: Concrete/Rod Monument
The bench mark is set in concrete atop of a copper-clad rod driven to refusal,
137 feet (42 m) SW of Bench Mark NO 1 1974, 50 feet (15 m) SE of the south shore
of the cut, 50 feet (15 m) NW of a drainage ditch running parallel to the cut,
and 0.8 foot (0.2 m) above the ground.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 4
PUBLICATION DATE: 06/16/1986
Station ID: 8724226 SUPERCEDED DATE: 04/21/2003
Name: BIG PINE KEY, NE SHORE, WEST OF BIG SPANISH CHANNE
FLORIDA
NOAA Chart: 11448 Latitude: 24° 43.7' N
USGS Quad: SUMMERLAND KEY Longitude: 81° 23.2' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 3 1974
MONUMENTATION: Survey Disk VM#: 8999
AGENCY: PID:
SETTING CLASSIFICATION: Concrete/Rod Monument
The bench mark is set in concrete atop of a copper-clad rod driven to refusal,
approximately 150 feet (46 m) south and 38 feet (12 m) east of the end of S-940,
70 feet (21 m) west of the north shore of the cut, 9 feet (3 m) north of a dirt
road leading to the cut, and 0.5 foot (0.2 m) above the ground.
BENCH MARK STAMPING: NO 4 1974
MONUMENTATION: Survey Disk VM#: 9000
AGENCY: PID:
SETTING CLASSIFICATION: Concrete/Rod Monument
The bench mark is set in concrete atop of a copper-clad rod driven to refusal,
166 feet (51 m) NW of Bench Mark NO 3 1974, 50 feet (15 m) south of a drainage
ditch running perpendicular to the road, 2 feet (1 m) north of the end of S-940,
and 0.5 foot (0.2 m) above the ground.
BENCH MARK STAMPING: NO 5 1974
MONUMENTATION: Survey Disk VM#: 9001
AGENCY: PID:
SETTING CLASSIFICATION: Concrete/Rod Monument
The bench mark is set in concrete atop of a copper-clad rod driven to refusal,
184 feet (56 m) SW of Bench Mark NO 4 1974, 150 feet (46 m) south and 43 feet
(13 m) west of the end of S-940, 101 feet (31 m) west of Bench Mark NO 3 1974,
35 feet (11 m) east of a drainage canal running parallel to the road, and 0.5
foot (0.2 m) above the ground.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 4
PUBLICATION DATE: 06/16/1986
Station ID: 8724226 SUPERCEDED DATE: 04/21/2003
Name: BIG PINE KEY, NE SHORE, WEST OF BIG SPANISH CHANNE
FLORIDA
NOAA Chart: 11448 Latitude: 24° 43.7' N
USGS Quad: SUMMERLAND KEY Longitude: 81° 23.2' W
T I D A L D A T U M S
Tidal datums at BIG PINE KEY, NE SHORE, WEST OF BIG SPANISH CHANNE based on:
LENGTH OF SERIES: 1 MONTH
TIME PERIOD: OCTOBER 1974
TIDAL EPOCH: 1960-1978
CONTROL TIDE STATION: 8724580 KEY WEST
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET:
MEAN HIGHER HIGH WATER (MHHW) = 1.52
MEAN HIGH WATER (MHW) = 1.34
MEAN TIDE LEVEL (MTL) = 0.80
MEAN LOW WATER (MLW) = 0.26
MEAN LOWER LOW WATER (MLLW) = 0.00
National Geodetic Vertical Datum (NGVD 29)
Bench Mark Elevation Information In FEET above:
Stamping or Designation MLLW MHW
NO 1 1974 2.48 1.14
NO 2 1974 2.96 1.62
NO 3 1974 3.08 1.74
NO 4 1974 3.93 2.59
NO 5 1974 3.31 1.97
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 4
PUBLICATION DATE: 06/16/1986
Station ID: 8724226 SUPERCEDED DATE: 04/21/2003
Name: BIG PINE KEY, NE SHORE, WEST OF BIG SPANISH CHANNE
FLORIDA
NOAA Chart: 11448 Latitude: 24° 43.7' N
USGS Quad: SUMMERLAND KEY Longitude: 81° 23.2' W
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 (NAVD 88).
NGVD 29 is a fixed datum adopted as a national standard geodetic reference for
heights but is now considered superseded. NGVD 29 is sometimes referred to as
Sea Level Datum of 1929 or as Mean Sea Level on some early issues of Geological
Survey Topographic Quads. NGVD 29 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 NGVD 29 are available from the National
Geodetic Survey (NGS) data base via the World Wide Web at
National Geodetic Survey.
NAVD 88 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. NAVD 88 replaces NGVD 29 as the national
standard geodetic reference for heights. Bench mark elevations relative to
NAVD 88 are available from NGS through the World Wide Web at
National Geodetic Survey.
NGVD 29 and NAVD 88 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 NAVD 88 elevation is shown on the Elevations of Tidal Datums Table Referred
to MLLW only when two or more of the bench marks listed have NAVD 88 elevations.
The NAVD 88 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, NAVD 88 bench mark elevations computed indirectly from the tidal
datums elevation table may differ slightly from NAVD 88 elevations listed for
each bench mark in the NGS database.