U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 8726641 PUBLICATION DATE: 04/21/2003
Name: GANDY BRIDGE, OLD TAMPA BAY
FL
NOAA Chart: 11413 Latitude: 27° 53.6' N ( 27.89330)
USGS Quad: GANDY BRIDGE Longitude: 82° 32.3' W ( -82.53830)
To reach the tidal bench marks from the east end of the Gandy Boulevard (U.S.
Highway 92) bridge in Tampa, proceed east on Gandy Boulevard for 0.3 km (0.2 mi)
to the U.S. Marine Corps Reserve Training Center. The bench marks are at the
Reserve Training Center and along Gandy Boulevard. The tide gauge and staff
were on the on the bulkhead behind the U.S. Marine Corps Reserve Training
Center.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: NO 1 1975
DESIGNATION: 872 6641 TIDAL 1 1975
MONUMENTATION: Tidal Station disk VM#: 6641
AGENCY: National Ocean Survey (NOS) IDB PID#: AG6401
SETTING CLASSIFICATION: Concrete sea wall OPUS PID:
LATITUDE: 27° 53.6' N ( 27.89330) LONGITUDE: 82° 32.4' W ( -82.54000)
The primary bench mark is a disk set on top of the sea wall in the SE corner of
a ramp at the Marine Reserve Training Center, 0.43 m (1.4 ft) NW of the SE
corner fence post at the SE corner of the ramp.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 8726641 PUBLICATION DATE: 04/21/2003
Name: GANDY BRIDGE, OLD TAMPA BAY
FL
NOAA Chart: 11413 Latitude: 27° 53.6' N ( 27.89330)
USGS Quad: GANDY BRIDGE Longitude: 82° 32.3' W ( -82.53830)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: G 263 1966
DESIGNATION: G 263
MONUMENTATION: Bench Mark disk VM#: 6640
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: AG5351
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID:
LATITUDE: 27° 53.6' N ( 27.89330) LONGITUDE: 82° 32.3' W ( -82.53830)
The bench mark is a disk located near the NE corner of the steel fence around
the Marine Reserve Training Center, 119 m (390 ft) north of Gandy Boulevard, 10
m (34 ft) east of the NE corner of the main office building, 5.94 m (19.5 ft) SE
of the SE corner of a 2 m (7 ft) square concrete building, and 0.3 m (1 ft) NE
of a metal witness post. The bench mark is a disk crimped to a copper-clad
steel rod driven 15.2 m (50 ft) to refusal, and encased in a 6-inch iron pipe
projecting 0.12 m (0.4 ft) above the level of the boulevard.
BENCH MARK STAMPING: 6641 F 1990
DESIGNATION: 872 6641 F
MONUMENTATION: Tidal Station disk VM#: 6643
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Flagpole base OPUS PID#: DM1528
LATITUDE: 27° 53.6' N ( 27.89330) LONGITUDE: 82° 32.3' W ( -82.53830)
The bench mark is a disk set flush in the concrete base for a flagpole in front
of the US Marine Corps Rerserve Training Center, 39 m (128 ft) north of the
north edge of the westbound land of Gandy Boulevard, 23 m (75 ft) NE of a 1 m x
1 m (4 ft x 3 ft) rectangular concrete stormwater catch basin, 19.14 m (62.8 ft)
south of south face of the Marine Corps building, 0.46 m (1.5 ft) NW of the
flagpole, and level with the ground.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 8726641 PUBLICATION DATE: 04/21/2003
Name: GANDY BRIDGE, OLD TAMPA BAY
FL
NOAA Chart: 11413 Latitude: 27° 53.6' N ( 27.89330)
USGS Quad: GANDY BRIDGE Longitude: 82° 32.3' W ( -82.53830)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING:
DESIGNATION: 872 6641 SRD
ALIAS: NO STAMPING 1
MONUMENTATION: Survey disk VM#: 6644
AGENCY: Florida State Road Department (FLSRD) IDB PID#:
SETTING CLASSIFICATION: Concrete guardrail OPUS PID:
LATITUDE: 27° 53.6' N ( 27.89330) LONGITUDE: 82° 32.3' W ( -82.53830)
The bench mark is a disk set in the top of the concrete guard rail at the east
end of Gandy Bridge, 59 m (192 ft) south of the centerline of the westbound land
of Gandy Boulevard, 27 m (90 ft) east along the bridge from the intersection of
the seawall and the bridge, 7 m (23 ft) south of the centerline of the eastbound
lane of Gandy Boulevard, 1 m (2 ft) west of the east end of the guard rail, and
1 m (3 ft) above the road surface at the SE corner of the bridge.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 8726641 PUBLICATION DATE: 04/21/2003
Name: GANDY BRIDGE, OLD TAMPA BAY
FL
NOAA Chart: 11413 Latitude: 27° 53.6' N ( 27.89330)
USGS Quad: GANDY BRIDGE Longitude: 82° 32.3' W ( -82.53830)
T I D A L D A T U M S
Tidal datums at GANDY BRIDGE, OLD TAMPA BAY based on:
LENGTH OF SERIES: 5 Months
TIME PERIOD: January 1991 - May 1991
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8726520 ST. PETERSBURG, TAMPA BAY
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 0.778
MEAN HIGH WATER MHW = 0.677
North American Vertical Datum NAVD88 = 0.495
MEAN TIDE LEVEL MTL = 0.410
MEAN SEA LEVEL MSL = 0.409
MEAN LOW WATER MLW = 0.144
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
NO 1 1975 2.323 1.646
G 263 1966 2.513 1.836
6641 F 1990 2.526 1.849
872 6641 SRD 5.243 4.566
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 8726641 PUBLICATION DATE: 04/21/2003
Name: GANDY BRIDGE, OLD TAMPA BAY
FL
NOAA Chart: 11413 Latitude: 27° 53.6' N ( 27.89330)
USGS Quad: GANDY BRIDGE Longitude: 82° 32.3' W ( -82.53830)
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 NGS's Integrated Data Base (IDB PID)
provides geodetic datum based on traditionally leveled and bluebooked ties to
the National Spatial Reference System(NSRS) https://www.ngs.noaa.gov/datasheets/.
The NGS Online Positioning User Service (OPUS PID) provides geodetic datum based
on GPS position & tie it to the NSRS https://www.ngs.noaa.gov/OPUS/.
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.