U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 4
PUBLICATION DATE: 03/29/1984
Station ID: 8726666 SUPERCEDED DATE: 04/21/2003
Name: BELLEAIR, CLEARWATER HARBOR
FLORIDA
NOAA Chart: 11410 Latitude: 27° 55.1' N
USGS Quad: CLEARWATER Longitude: 82° 49.6' W
To reach the tidal bench marks from the intersection of alternate U.S. Route 19,
and Florida State Route 686 (West Bay Drive) in Largo, go 1.9 miles (3.1 km)
west on State Route 686 to the Belleair Beach Causeway public boat ramps. The
bench marks are located along West Bay Drive and the boat ramps, and gage and
staff were on the wooden pier next to the bait house.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 6666 A 1976
MONUMENTATION: Survey Disk VM#: 6815
AGENCY: PID#: AG7444
SETTING CLASSIFICATION: Concrete Base
The bench mark is located on the third concrete base for a floating dock, west
from the easternmost floating dock, 155 feet (47.2 m) east of the east corner of
the bait house, 41 feet (12.5 m) north of the centerline for the road to the
parking area, and 2 feet (0.6 m) east of the west edge of the concrete base.
BENCH MARK STAMPING: 6666 B 1976
MONUMENTATION: Survey Disk VM#: 6816
AGENCY: PID#: AG7443
SETTING CLASSIFICATION: Concrete Wall
The bench mark is located in the south end of a concrete wall that projects out
into the water, 123 feet (37.5 m) west of the west corner of the bait house.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 4
PUBLICATION DATE: 03/29/1984
Station ID: 8726666 SUPERCEDED DATE: 04/21/2003
Name: BELLEAIR, CLEARWATER HARBOR
FLORIDA
NOAA Chart: 11410 Latitude: 27° 55.1' N
USGS Quad: CLEARWATER Longitude: 82° 49.6' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: HALL A
MONUMENTATION: Survey Disk VM#: 6817
AGENCY: PID#: AG0552
SETTING CLASSIFICATION: Concrete Post
The bench mark is set in a concrete post 1 foot (0.3 m) in diameter, 24.0 feet
(7.3 m) north of the centerline of the road to the parking area, 20.5 feet (6.2
m) SE of the NW corner of a sea wall, and 1 foot (0.3 m) east of a witness post.
BENCH MARK STAMPING: IWPI 4 1959
MONUMENTATION: Survey Disk VM#: 6818
AGENCY: PID#: AG0637
SETTING CLASSIFICATION: Concrete Bridge Pavement
The bench mark is set flush in the road surface of the Belleair Beach Causeway
Bridge, 10.5 feet (3.2 m) south of the centerline of the road, 6.7 feet (2.0 m)
north of Florida State Road Department Bench Mark 215, and 1.4 feet (0.4 m)
north of the curve in the road.
BENCH MARK STAMPING: 215
MONUMENTATION: Survey Disk VM#: 6819
AGENCY: PID#: AG0113
SETTING CLASSIFICATION: Concrete Bridge Wing Wall
The bench mark is located in the SE corner of the Belleaire Beach Causeway
Bridge, 17.3 feet (5.3 m) south of the centerline of the bridge, and 0.6 foot
(0.2 m) west of the east edge of the bridge.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 4
PUBLICATION DATE: 03/29/1984
Station ID: 8726666 SUPERCEDED DATE: 04/21/2003
Name: BELLEAIR, CLEARWATER HARBOR
FLORIDA
NOAA Chart: 11410 Latitude: 27° 55.1' N
USGS Quad: CLEARWATER Longitude: 82° 49.6' W
T I D A L D A T U M S
Tidal datums at BELLEAIR, CLEARWATER HARBOR based on:
LENGTH OF SERIES: 1 MONTH
TIME PERIOD: JUNE 1976
TIDAL EPOCH: 1960-1978
CONTROL TIDE STATION: 8726724 CLEARWATER BEACH
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET:
HIGHEST OBSERVED WATER LEVEL (05/28/1976) = 4.07
MEAN HIGHER HIGH WATER MHHW = 2.87
MEAN HIGH WATER MHW = 2.49
MEAN TIDE LEVEL MTL = 1.51
MEAN LOW WATER MLW = 0.53
MEAN LOWER LOW WATER MLLW = 0.00
LOWEST OBSERVED WATER LEVEL (04/02/1976) = -0.71
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In FEET above:
Stamping or Designation MLLW MHW
6666 A 1976 4.95 2.46
6666 B 1976 5.76 3.27
HALL A 5.48 2.99
IWPI 4 1959 13.19 10.70
215 13.97 11.48
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 4
PUBLICATION DATE: 03/29/1984
Station ID: 8726666 SUPERCEDED DATE: 04/21/2003
Name: BELLEAIR, CLEARWATER HARBOR
FLORIDA
NOAA Chart: 11410 Latitude: 27° 55.1' N
USGS Quad: CLEARWATER Longitude: 82° 49.6' 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.