U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
PUBLICATION DATE: 02/02/1989
Station ID: 8726995 SUPERCEDED DATE: 04/21/2003
Name: GULF HARBORS, GULF OF MEXICO
FLORIDA
NOAA Chart: 11409 Latitude: 28° 14.6' N
USGS Quad: TARPON SPRINGS Longitude: 82° 45.8' W
To reach the tidal bench marks from the intersection of U.S. Highways 19 and
19A, proceed north on U.S. Highway 19 for 3.35 miles (5.39 km) to Floramar
Terrace (entrance to Gulf Harbors), then west on Floramar Terrace for 2.3 miles
(3.7 km) to the Gulf Harbors private beach. The bench marks are in the vicinity
of the bathhouse, picnic shelters, and along Floramar Terrace. The tide gage
and staff were in the canal north of the picnic area, and just to the west of
the canal entrance.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 6995 C 1976
MONUMENTATION: Survey Disk VM#: 7690
AGENCY: PID#: AL7462
SETTING CLASSIFICATION: Concrete Slab
The bench mark is set in a 4 x 4 foot (1 x 1 m) concrete slab near the
bathhouse, 29.6 feet (9.0 m) east of the centerline of the beach road, 10 feet
(3 m) WNW of the NE corner of the bathhouse, and 8.1 feet (2.5 m) ENE of the NW
corner of the bathhouse.
BENCH MARK STAMPING: 6995 E 1976
MONUMENTATION: Survey Disk VM#: 7691
AGENCY: PID#: AL7463
SETTING CLASSIFICATION: Concrete Slab
The bench mark is set in the NW corner of the concrete floor for the third
picnic shelter north of the southernmost picnic shelter, and 74.6 feet (22.7 m)
west of the centerline of the beach road.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
PUBLICATION DATE: 02/02/1989
Station ID: 8726995 SUPERCEDED DATE: 04/21/2003
Name: GULF HARBORS, GULF OF MEXICO
FLORIDA
NOAA Chart: 11409 Latitude: 28° 14.6' N
USGS Quad: TARPON SPRINGS Longitude: 82° 45.8' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 6995 F 1976
MONUMENTATION: Survey Disk VM#: 7692
AGENCY: PID#: AL7461
SETTING CLASSIFICATION: Copper-clad Steel Rod
The bench mark is in front of the bathhouse, 79.8 feet (24.3 m) west of the
centerline of the beach road, 45 feet (14 m) SW of the SW corner of the seventh
picnic shelter, north of the southernmost picnic shelter, and 2.8 feet (0.9 m)
east of the easternmost of three palm trees. The bench mark is crimped to a
copper-clad steel rod driven 50 feet (15 m), and encased in a pipe projecting
0.1 foot (0.03 m).
BENCH MARK STAMPING: 6995 G 1983
MONUMENTATION: Survey Disk VM#: 7693
AGENCY: PID#: AL7460
SETTING CLASSIFICATION: Concrete Wall
The bench mark is set in top of a 3-foot (1 m) high concrete wall around a
circular pond near the gate house for the picnic and beach area, 114.5 feet
(34.9 m) south of the centerline of the entrance road to the beach, 21.0 feet
(6.4 m) east of the centerline of the Floramar Terrace circle, 15.1 feet (4.6 m)
NW of a culvert, and 6.8 feet (2.1 m) NNE of the center of a manhole for a box
drain.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
PUBLICATION DATE: 02/02/1989
Station ID: 8726995 SUPERCEDED DATE: 04/21/2003
Name: GULF HARBORS, GULF OF MEXICO
FLORIDA
NOAA Chart: 11409 Latitude: 28° 14.6' N
USGS Quad: TARPON SPRINGS Longitude: 82° 45.8' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 6995 H 1983
MONUMENTATION: Survey Disk VM#: 7694
AGENCY: PID#: AL7459
SETTING CLASSIFICATION: Concrete Monument
The bench mark is set in a concrete monument, 500 feet (152 m) east of the
entrance to the private beach, 57.5 feet (17.5 m) NNE of the centerline of
Floramar Terrace, 43.6 feet (13.3 m) ESE of a fence corner, 18 feet (5 m) NE of
the center of a manhole that projects 2 feet (1 m) above ground, 4.5 feet (1.4
m) SSW of a chain link fence, and at ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
PUBLICATION DATE: 02/02/1989
Station ID: 8726995 SUPERCEDED DATE: 04/21/2003
Name: GULF HARBORS, GULF OF MEXICO
FLORIDA
NOAA Chart: 11409 Latitude: 28° 14.6' N
USGS Quad: TARPON SPRINGS Longitude: 82° 45.8' W
T I D A L D A T U M S
Tidal datums at GULF HARBORS, GULF OF MEXICO based on:
LENGTH OF SERIES: 56 HWS - 56 LWS
TIME PERIOD: AUGUST 17 - SEPTEMBER 14, 1976
TIDAL EPOCH: 1960-1978
CONTROL TIDE STATION: 8726924 ANCLOTE, ANCLOTE RIVER
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET:
HIGHEST OBSERVED WATER LEVEL (09/22/1976) = 4.09
MEAN HIGHER HIGH WATER MHHW = 3.26
MEAN HIGH WATER MHW = 2.87
MEAN TIDE LEVEL MTL = 1.72
MEAN LOW WATER MLW = 0.57
MEAN LOWER LOW WATER MLLW = 0.00
LOWEST OBSERVED WATER LEVEL (08/24/1976) = -0.17
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In FEET above:
Stamping or Designation MLLW MHW
6995 C 1976 7.85 4.98
6995 E 1976 6.99 4.12
6995 F 1976 6.86 3.99
6995 G 1983 9.85 6.98
6995 H 1983 7.68 4.81
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
PUBLICATION DATE: 02/02/1989
Station ID: 8726995 SUPERCEDED DATE: 04/21/2003
Name: GULF HARBORS, GULF OF MEXICO
FLORIDA
NOAA Chart: 11409 Latitude: 28° 14.6' N
USGS Quad: TARPON SPRINGS Longitude: 82° 45.8' 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.