U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 4
PUBLICATION DATE: 04/22/1985
Station ID: 8725114 SUPERCEDED DATE: 04/21/2003
Name: NORTH END, NAPLES BAY
FLORIDA
NOAA Chart: 11429 Latitude: 26° 8.2' N
USGS Quad: NAPLES NORTH Longitude: 81° 47.3' W
To reach the tidal bench marks from the 90 degree bend in U.S. Highway 41 in the
city of Naples, proceed east 0.35 mile (0.56 km) to the first bridge over the
Gordon River, turn right onto River Point Drive, and proceed to the Naples
Sailing and Yacht Club. The bench marks are in the vicinity of the bridge and
Yacht Club. The gage and staff were on a dock on the south end of the property.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 5114 A 1978
MONUMENTATION: Survey Disk VM#: 7893
AGENCY: PID#: AD6328
SETTING CLASSIFICATION: Concrete Manhole Cover
The bench mark is set flush on the west side of a 3x4 foot (1x1 m) manhole cover
at the Naples Sailing and Yacht Club, 300 feet (91 m) south of the south side of
the pavement of the south bound lane of U.S. Highway 41, 26.0 feet (7.9 m) west
of the centerline of River Point Drive, and 1 foot (0.3 m) SW of the NW corner
of the most western lid of the manhole cover.
BENCH MARK STAMPING: BMT A 47
MONUMENTATION: Survey Disk VM#: 7840
AGENCY: PID#: AD6329
SETTING CLASSIFICATION: Concrete Seawall
The bench mark is set flush in the NE end of the seawall SW of the Naples
Sailing and Yacht Club, 287 feet (87 m) north of Bench Mark BMT B 48, and 0.8
foot (0.2 m) SW of the NE corner of the seawall.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 4
PUBLICATION DATE: 04/22/1985
Station ID: 8725114 SUPERCEDED DATE: 04/21/2003
Name: NORTH END, NAPLES BAY
FLORIDA
NOAA Chart: 11429 Latitude: 26° 8.2' N
USGS Quad: NAPLES NORTH Longitude: 81° 47.3' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: BMT B 48
MONUMENTATION: Survey Disk VM#: 7841
AGENCY: PID#: AD6330
SETTING CLASSIFICATION: Concrete Seawall
The bench mark is set flush in the SE corner of the Naples Sailing and Yacht
Club, 49.0 feet (14.9 m) south of the SE corner of the club building, 48.0 feet
(14.6 m) east of the east corner of the club patio, and 0.6 foot (0.2 m) north
of the south face of the seawall.
BENCH MARK STAMPING: BMT C 49
MONUMENTATION: Survey Disk VM#: 7842
AGENCY: PID#: AD6331
SETTING CLASSIFICATION: Concrete Seawall
The bench mark is set flush in the south seawall of the Naples Sailing and Yacht
Club, 161.0 feet (49.1 m) SW of Bench Mark BMT B 48, 118.0 feet (36 m) north of
the south end of a boat pier, 51.0 feet (15.5 m) SW of the SW corner of the club
building, 43.0 feet (13.1 m) SW of a flagpole, and 0.6 foot (0.2 m) north of the
south face of the seawall.
BENCH MARK STAMPING: 14.98
MONUMENTATION: Survey Disk VM#: 7843
AGENCY: PID#: AD1249
SETTING CLASSIFICATION: Concrete Bridge Post
The bench mark is set flush in the top of the concrete end post at the SE end of
the NW one of two U.S. Highway 41 bridges over Gordon River, at the NE corner of
the bridge, 5.0 feet (1.5 m) NE of the NE curb, and 3.2 feet (1.0 m) above the
sidewalk.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 4
PUBLICATION DATE: 04/22/1985
Station ID: 8725114 SUPERCEDED DATE: 04/21/2003
Name: NORTH END, NAPLES BAY
FLORIDA
NOAA Chart: 11429 Latitude: 26° 8.2' N
USGS Quad: NAPLES NORTH Longitude: 81° 47.3' W
T I D A L D A T U M S
Tidal datums at NORTH END, NAPLES BAY based on:
LENGTH OF SERIES: 6 MONTHS
TIME PERIOD: APRIL-SEPTEMBER 1978
TIDAL EPOCH: 1960-1978
CONTROL TIDE STATION: 8725110 NAPLES
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET:
HIGHEST OBSERVED WATER LEVEL (05/04/1978) = 3.60
MEAN HIGHER HIGH WATER MHHW = 2.85
MEAN HIGH WATER MHW = 2.61
MEAN TIDE LEVEL MTL = 1.58
MEAN LOW WATER MLW = 0.55
MEAN LOWER LOW WATER MLLW = 0.00
LOWEST OBSERVED WATER LEVEL (04/19/1978) = -0.86
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In FEET above:
Stamping or Designation MLLW MHW
5114 A 1978 7.23 0.62
BMT A 47 4.84 2.23
BMT B 48 4.95 2.34
BMT C 49 4.91 2.30
14.98 16.10 13.49
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 4
PUBLICATION DATE: 04/22/1985
Station ID: 8725114 SUPERCEDED DATE: 04/21/2003
Name: NORTH END, NAPLES BAY
FLORIDA
NOAA Chart: 11429 Latitude: 26° 8.2' N
USGS Quad: NAPLES NORTH Longitude: 81° 47.3' 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.