U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 7
Station ID: 8722859 PUBLICATION DATE: 12/12/2003
Name: HILLSBORO
FL
NOAA Chart: 11466 Latitude: 26° 15.6' N ( 26.26000)
USGS Quad: BOCA RATON Longitude: 80° 5.1' W ( -80.08500)
To reach the tidal bench marks from the State Highway A1A drawbridge over
Hillsboro Inlet, proceed south on State Highway A1A for 0.2 km (0.1 mi) to North
Riverside Drive, then turn right and proceed west on North Riverside Drive to
the Hillsboro Inlet Marina at 2635 North Riverside Drive. The bench marks are
located in the vicinity of the State Highway A1A bridge over Hillsboro Inlet,
the Hillsboro Inlet Marina, and the U.S. Coast Guard Station. The gage and tide
staff were located on the fuel dock at the Hillsboro Inlet Marina.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: NO 1 1973
DESIGNATION: 872 2859 TIDAL 1
MONUMENTATION: Tidal Station disk VM#: 5665
AGENCY: National Ocean Survey (NOS) IDB PID#: AD5849
SETTING CLASSIFICATION: Concrete sea wall OPUS PID:
LATITUDE: 26° 15.6' N ( 26.26000) LONGITUDE: 80° 5.1' W ( -80.08500)
The primary bench mark is a disk set flush in the concrete sea wall west of the
Hillsboro Inlet Marina Building, 12.04 m (39.5 ft) south of the north boundary
of the marina property, 11.73 m (38.5 ft) south of bench mark NO 2 1973, and
1.22 m (4.0 ft) south of the centerline of the pier. NOTE: Mark not found in
2002 by US Power Squadron.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 7
Station ID: 8722859 PUBLICATION DATE: 12/12/2003
Name: HILLSBORO
FL
NOAA Chart: 11466 Latitude: 26° 15.6' N ( 26.26000)
USGS Quad: BOCA RATON Longitude: 80° 5.1' W ( -80.08500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: Y 311 1970
DESIGNATION: Y 311
MONUMENTATION: Bench Mark disk VM#: 5663
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: AD2604
SETTING CLASSIFICATION: Concrete lighthouse foundation OPUS PID:
LATITUDE: 26° 15.5' N ( 26.25830) LONGITUDE: 80° 4.9' W ( -80.08167)
The bench mark is a disk at the U.S. Coast Guard Station and light house, 51 m
(168 ft) south of bench mark Z 311 1970, 4.45 m (14.6 ft) west of the SE leg of
the lighthouse, 3 m (10 ft) south of the SE corner of the steps leading up to
the lighthouse, and level with the ground.
BENCH MARK STAMPING: NO 2 1973
DESIGNATION: 872 2859 TIDAL 2
MONUMENTATION: Tidal Station disk VM#: 5666
AGENCY: National Ocean Survey (NOS) IDB PID#: AD5850
SETTING CLASSIFICATION: Concrete sea wall OPUS PID:
LATITUDE: 26° 15.6' N ( 26.26000) LONGITUDE: 80° 5.1' W ( -80.08500)
The bench mark is a disk set flush in the concrete sea wall west of the
Hillsboro Inlet Marina Building, 10.52 m (34.5 ft) north of the centerline of
the pier, and 0.30 m (1.0 ft) south of the north boundary of the marina
property.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 7
Station ID: 8722859 PUBLICATION DATE: 12/12/2003
Name: HILLSBORO
FL
NOAA Chart: 11466 Latitude: 26° 15.6' N ( 26.26000)
USGS Quad: BOCA RATON Longitude: 80° 5.1' W ( -80.08500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 3 1973
DESIGNATION: 872 2859 TIDAL 3
MONUMENTATION: Tidal Station disk VM#: 5667
AGENCY: National Ocean Survey (NOS) IDB PID#: AD5848
SETTING CLASSIFICATION: Concrete curb OPUS PID:
LATITUDE: 26° 15.6' N ( 26.26000) LONGITUDE: 80° 5.1' W ( -80.08500)
The bench mark is a disk set flush in the concrete curb near a drain, 67.1 m
(220.0 ft) south of the south end of State Highway A1A bridge over Hillsboro
Inlet and bench mark NO 4 1973, and 5.49 m (18.0 ft) west of the centerline of
the highway.
BENCH MARK STAMPING: NO 4 1973
DESIGNATION: 872 2859 TIDAL 4
MONUMENTATION: Tidal Station disk VM#: 5668
AGENCY: National Ocean Survey (NOS) IDB PID#: AD5846
SETTING CLASSIFICATION: Concrete sidewalk OPUS PID:
LATITUDE: 26° 15.6' N ( 26.26000) LONGITUDE: 80° 5.1' W ( -80.08500)
The bench mark is a disk set flush in the concrete sidewalk on the south end of
State Highway A1A bridge over Hillsboro Inlet, 5 m (16.0 ft) west of the
centerline of the bridge, and 0.34 m (1.1 ft) west of the east edge of the curb.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 7
Station ID: 8722859 PUBLICATION DATE: 12/12/2003
Name: HILLSBORO
FL
NOAA Chart: 11466 Latitude: 26° 15.6' N ( 26.26000)
USGS Quad: BOCA RATON Longitude: 80° 5.1' W ( -80.08500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 5 1973
DESIGNATION: 872 2859 TIDAL 5
MONUMENTATION: Tidal Station disk VM#: 5669
AGENCY: National Ocean Survey (NOS) IDB PID#: AD5847
SETTING CLASSIFICATION: Concrete bridge abutment OPUS PID:
LATITUDE: 26° 15.7' N ( 26.26167) LONGITUDE: 80° 5.0' W ( -80.08333)
The bench mark is a disk set flush in the concrete bridge abutment foundation
under the south end of State Highway A1A bridge over Hillsboro Inlet, 60.96 m
(200.0 ft) north of bench mark NO 4 1973, 10.52 m (34.5 ft) south of the
concrete sea wall, and 4.57 m (15.0 ft) south of the centerline of a paved road
under the bridge.
BENCH MARK STAMPING: 16.770
DESIGNATION: 16.770 FLHD
MONUMENTATION: Survey disk VM#: 5670
AGENCY: Florida State Road Department (FLSRD) IDB PID#: AD2608
SETTING CLASSIFICATION: Concrete bridge sidewalk OPUS PID:
LATITUDE: 26° 15.6' N ( 26.26000) LONGITUDE: 80° 5.0' W ( -80.08333)
The bench mark is a disk set in the SE concrete sidewalk of State Highway A1A
bridge over Hillsboro Inlet, 60 m (198 ft) NE of the SW end of the bridge, 5 m
(15 ft) SE of the centerline of the highway, 0.3 m (1 ft) SE of the NW edge of
the sidewalk, and 0.3 m (1 ft) above the level of the bridge floor.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 7
Station ID: 8722859 PUBLICATION DATE: 12/12/2003
Name: HILLSBORO
FL
NOAA Chart: 11466 Latitude: 26° 15.6' N ( 26.26000)
USGS Quad: BOCA RATON Longitude: 80° 5.1' W ( -80.08500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 18.090
DESIGNATION: 18.090 FLHD
MONUMENTATION: Survey disk VM#: 5671
AGENCY: Florida State Road Department (FLSRD) IDB PID#: AD2607
SETTING CLASSIFICATION: Concrete bridge curb OPUS PID:
LATITUDE: 26° 15.7' N ( 26.26170) LONGITUDE: 80° 5.0' W ( -80.08330)
The bench mark is a disk set in the NW curb of the State Highway A1A Bridge,
over Hillsboro Inlet 4.75 m (15.6 ft) NW of the centerline of the highway, 3 m
(7 ft) SW of the NE end of the bannister, and 0.3 m (1 ft) above the level of
the highway. NOTE: Mark not found in 2001 & 2002 by US Power Squadron.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 7
Station ID: 8722859 PUBLICATION DATE: 12/12/2003
Name: HILLSBORO
FL
NOAA Chart: 11466 Latitude: 26° 15.6' N ( 26.26000)
USGS Quad: BOCA RATON Longitude: 80° 5.1' W ( -80.08500)
T I D A L D A T U M S
Tidal datums at HILLSBORO based on:
LENGTH OF SERIES: 6 MONTHS
TIME PERIOD: May 1973 - October 1973
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8723170 MIAMI BEACH (CITY PIER)
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 0.816
MEAN HIGH WATER MHW = 0.777
North American Vertical Datum NAVD88 = 0.682
MEAN TIDE LEVEL MTL = 0.411
MEAN SEA LEVEL MSL = 0.407
MEAN LOW WATER MLW = 0.045
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 1973 1.576 0.799
Y 311 1970 3.614 2.837
NO 2 1973 1.596 0.819
NO 3 1973 1.329 0.552
NO 4 1973 2.420 1.643
NO 5 1973 1.685 0.908
16.770 5.295 4.518
18.090 5.697 4.920
Foot Notes:
Bench marks Y 311 1970, 16.770, and 18.090 are based on one differential
leveling connection and do not meet the quality control standards of the NOS.
Therefore, caution should be used when deriving elevations for these marks.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 7 of 7
Station ID: 8722859 PUBLICATION DATE: 12/12/2003
Name: HILLSBORO
FL
NOAA Chart: 11466 Latitude: 26° 15.6' N ( 26.26000)
USGS Quad: BOCA RATON Longitude: 80° 5.1' W ( -80.08500)
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.