U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 8726693 PUBLICATION DATE: 07/26/2004
Name: HILLSBOROUGH RIVER ENTRANCE
FL
NOAA Chart: 11413 Latitude: 27° 56.8' N ( 27.94670)
USGS Quad: TAMPA Longitude: 82° 27.7' W ( -82.46170)
To reach the tidal bench marks from the intersection of Platt Street and
Bayshore Boulevard just SW of the Platt Street bridge over Hillsborough River in
downtown Tampa, proceed south on Bayshore Boulevard for 0.2 km (0.1 mi) to the
red brick parking area on the left. The bench marks are on the bridge and in
the vicinity of the Columbus monument north of the parking area. The tide gauge
and staff were on the City of Tampa wharf east of the parking area.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: HILLS 79.49
DESIGNATION: 872 6693 HILLS 79.49
MONUMENTATION: Survey disk VM#: 7513
AGENCY: US Army Corps of Engineers (USE) IDB PID#:
SETTING CLASSIFICATION: Concrete steps OPUS PID:
LATITUDE: 27° 56.8' N ( 27.94670) LONGITUDE: 82° 27.7' W ( -82.46170)
The primary bench mark is a disk set in the top of the steps of the sidewalk
that leads down from the Hillsborough River, 11 m (36 ft) SE of the SE curb of
the drive, 1.34 m (4.4 ft) NE of the SE corner of the landing, and about 1 m (2
ft) below the level of the drive.
BENCH MARK STAMPING: B 399 1990
DESIGNATION: 872 6693 B 399
MONUMENTATION: Survey disk VM#: 7514
AGENCY: Florida Department of Natural Resources
(FLDNR) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 27° 56.8' N ( 27.94670) LONGITUDE: 82° 27.7' W ( -82.46170)
The bench mark is a disk located 41 m (136 ft) south of the intersection of
Platt Street and Bayshore Boulevard, 14.97 m (49.1 ft) east of the centerline of
Bayshore Boulevard, 15.54 m (51.0 ft) west of a statue of Christopher Columbus,
6.92 m (22.7 ft) west of the of the west outside edge of a fountain wall, and
6.46 m (21.2 ft) NE of an aluminum street light pole. The bench mark is crimped
to the top of a stainless steel rod driven to an unspecified depth.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 8726693 PUBLICATION DATE: 07/26/2004
Name: HILLSBOROUGH RIVER ENTRANCE
FL
NOAA Chart: 11413 Latitude: 27° 56.8' N ( 27.94670)
USGS Quad: TAMPA Longitude: 82° 27.7' W ( -82.46170)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 101 A THL 1950 JACKSONVILLE
DESIGNATION: THL 101 A
MONUMENTATION: Traverse Station disk VM#: 7516
AGENCY: US Army Corps of Engineers (USE) IDB PID#: AG9394
SETTING CLASSIFICATION: Bridge curb apron OPUS PID:
LATITUDE: 27° 56.5' N ( 27.94170) LONGITUDE: 82° 27.6' W ( -82.46000)
The bench mark is a disk set in the south sidewalk of the Platt Street bridge
over the Hillsborough River, 43 m (140 ft) east of the centerline of Bayshore
Boulevard, and 7.16 m (23.5 ft) south of the south curb of the Platt Street
bridge.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 8726693 PUBLICATION DATE: 07/26/2004
Name: HILLSBOROUGH RIVER ENTRANCE
FL
NOAA Chart: 11413 Latitude: 27° 56.8' N ( 27.94670)
USGS Quad: TAMPA Longitude: 82° 27.7' W ( -82.46170)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: HR 3 1949 JACKSONVILLE
DESIGNATION: HR 3
MONUMENTATION: Survey disk VM#: 7517
AGENCY: US Army Corps of Engineers (USE) IDB PID#: AG6031
SETTING CLASSIFICATION: Bridge curb apron OPUS PID:
LATITUDE: 27° 56.5' N ( 27.94170) LONGITUDE: 82° 27.6' W ( -82.46000)
The bench mark is a disk set in the sidewalk at the NW corner of the Platt
Street bridge over the Hillsborough River, 32.20 m (105.6 ft) east of the
centerline of Bayshore Boulevard, 7.50 m (24.6 ft) north of the centerline of
the Platt Street bridge, and 0.1 m (2.0 ft) north of the north bridge curb.
BENCH MARK STAMPING: NO III
DESIGNATION: 872 6693 TIDAL 3
MONUMENTATION: Tidal Station disk VM#: 7518
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: AG6032
SETTING CLASSIFICATION: Bridge curb apron OPUS PID:
LATITUDE: 27° 56.5' N ( 27.94170) LONGITUDE: 82° 27.5' W ( -82.45830)
The bench mark is a disk set in the sidewalk on the north side of the Platt
Street bridge over Hillsborough River, 128 m (420 ft) east of the intersection
of Bayshore Boulevard and Platt Street, 11 m (36 ft) north of the centerline of
the Platt Street bridge, 1.20 m (3.9 ft) east of the east wall of the bridge
tenders house, and 0.1 m (0.3 ft) south of the face of the north concrete guard
rail.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 8726693 PUBLICATION DATE: 07/26/2004
Name: HILLSBOROUGH RIVER ENTRANCE
FL
NOAA Chart: 11413 Latitude: 27° 56.8' N ( 27.94670)
USGS Quad: TAMPA Longitude: 82° 27.7' W ( -82.46170)
T I D A L D A T U M S
Tidal datums at HILLSBOROUGH RIVER ENTRANCE based on:
LENGTH OF SERIES: 58 High & Low waters
TIME PERIOD: July 25 - August 28, 1990
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 = 0.773
MEAN HIGH WATER MHW = 0.696
North American Vertical Datum NAVD88 = 0.449
MEAN SEA LEVEL MSL = 0.401
MEAN TIDE LEVEL MTL = 0.399
MEAN LOW WATER MLW = 0.101
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
HILLS 79.49 2.547 1.851
B 399 1990 1.636 0.940
101 A THL 1950 JACKSONVILLE 4.474 3.778
HR 3 1949 JACKSONVILLE 3.994 3.298
NO III 6.437 5.741
Foot Notes:
Bench mark B399 1990 is based on one differential leveling connection and does
not meet the quality control standards of the NOS. Therefore, caution should be
used when deriving elevations for this mark.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 8726693 PUBLICATION DATE: 07/26/2004
Name: HILLSBOROUGH RIVER ENTRANCE
FL
NOAA Chart: 11413 Latitude: 27° 56.8' N ( 27.94670)
USGS Quad: TAMPA Longitude: 82° 27.7' W ( -82.46170)
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.