U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 4
PUBLICATION DATE: 10/17/1984
Station ID: 8725362 SUPERCEDED DATE: 04/21/2003
Name: TARPEN BAY, SANIBEL ISLAND
FLORIDA
NOAA Chart: 11427 Latitude: 26° 26.6' N
USGS Quad: Sanibel Longitude: 82° 4.9' W
To reach the tidal bench marks, about 1.4 miles (2.2 km), west of the SW end of
the Sanibel Causeway Bridges on the east end of Sanibel Island, proceed 0.2 mile
(0.3 km), west on Palm Ridge Road from the Police Station on Sanibel Island,
continue 0.4 mile (0.6 km), to the Tarpoon Bay Marina. The bench marks are
along the waterfront in the marina, and the gage and staff were at the SW corner
of the wood dock.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 5362 A 1977
MONUMENTATION: Survey Disk VM#: 7293
AGENCY: PID#: AG9344
SETTING CLASSIFICATION: Concrete Foundation
The bench mark is at the Tarpon Bay Marina, 11.0 feet (3.4 m), north of the NE
corner of the main two story marine building, 2.3 feet (0.7 m), SW of the east
end of the concrete seawall and 1.4 feet (0.4 m), NW of the NW corner of a
walk-in freezer, and set flush into the concrete.
BENCH MARK STAMPING: 5362 C 1977
MONUMENTATION: Survey Disk VM#: 7295
AGENCY: PID#: AG9346
SETTING CLASSIFICATION: Concrete Seawall
The bench mark is at the Tarpon Bay Marina, 18.5 feet (5.6 m), west of the NW
corner of the one story gift shop building and 2.5 feet (0.8 m), SW of the NW
corner of the northern most corner of the seawall, set flush into the concrete.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 4
PUBLICATION DATE: 10/17/1984
Station ID: 8725362 SUPERCEDED DATE: 04/21/2003
Name: TARPEN BAY, SANIBEL ISLAND
FLORIDA
NOAA Chart: 11427 Latitude: 26° 26.6' N
USGS Quad: Sanibel Longitude: 82° 4.9' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 5362 E 1977
MONUMENTATION: Survey Disk VM#: 7296
AGENCY: PID#: AG9347
SETTING CLASSIFICATION: Concrete Seawall
The bench mark is at the Tarpon Bay Marina, 42.0 feet (12.8 m), SSW of bench
mark 5362 C 1977, 38.0 feet (11.6 m), west of the SW corner of the one story
gift shop building, 20.0 feet (6.1 m), east of the centerline of the boat ramp
and 1.0 feet (0.3 m), north of the south end of the seawall, set flush into the
concrete.
BENCH MARK STAMPING: 5362 F 1977
MONUMENTATION: Survey Disk VM#: 7297
AGENCY: PID#: AG9348
SETTING CLASSIFICATION: Concrete Seawall
The bench mark is at the Tarpon Bay Marina, 80.5 feet (24.5 m), WSW of bench
mark 5362 E 1977, 18.0 feet (5.5 m), north of the NW corner of a one story
building NW of the parking area and 11.5 feet (3.5 m), west of the east end of
the west seawall on the south side of the marina, set flush into the concrete.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 4
PUBLICATION DATE: 10/17/1984
Station ID: 8725362 SUPERCEDED DATE: 04/21/2003
Name: TARPEN BAY, SANIBEL ISLAND
FLORIDA
NOAA Chart: 11427 Latitude: 26° 26.6' N
USGS Quad: Sanibel Longitude: 82° 4.9' W
T I D A L D A T U M S
Tidal datums at TARPEN BAY, SANIBEL ISLAND based on:
LENGTH OF SERIES: 5 MONTHS
TIME PERIOD: 11/77, 12/77 and 1/78, 3/78
TIDAL EPOCH: 1960-1978
CONTROL TIDE STATION: 8725391 Punta Rassa
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET:
HIGHEST OBSERVED WATER LEVEL (01/09/1978) = 3.38
MEAN HIGHER HIGH WATER MHHW = 2.36
MEAN HIGH WATER MHW = 2.09
MEAN TIDE LEVEL MTL = 1.28
MEAN LOW WATER MLW = 0.46
MEAN LOWER LOW WATER MLLW = 0.00
LOWEST OBSERVED WATER LEVEL (01/11/1978) = -1.09
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In FEET above:
Stamping or Designation MLLW MHW
5362 A 1977 4.96 2.87
5362 C 1977 3.87 1.78
5362 E 1977 3.90 1.81
5362 F 1977 4.30 2.21
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 4
PUBLICATION DATE: 10/17/1984
Station ID: 8725362 SUPERCEDED DATE: 04/21/2003
Name: TARPEN BAY, SANIBEL ISLAND
FLORIDA
NOAA Chart: 11427 Latitude: 26° 26.6' N
USGS Quad: Sanibel Longitude: 82° 4.9' 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 (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 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.