Superseded Bench Mark Sheet for 8722859, HILLSBORO FL

Present Epoch

Printable version

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  6

                                                   PUBLICATION DATE:  10/26/1987
Station ID: 8722859                                SUPERCEDED DATE:   04/21/2003
Name:       HILLSBORO INLET MARINA, POMPANO BEACH, INTRACOASTA
            FLORIDA
NOAA Chart: 11466                                  Latitude:         26° 15.6' N
USGS Quad:  BOCA RATON                             Longitude:        80°  5.1' W


To reach the tidal bench marks from State Highway A1A drawbridge, over Hillsboro
Inlet, proceed south on State Highway A1A for 0.1 mile (0.2 km) to North
Riverside Drive.  The NW on North Riverside Drive to the Hillsboro Inlet Marina
at 2635 North Riverside Drive.  The bench marks are located in the vicinity of
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

MONUMENTATION:           Survey Disk                               VM#:     5665
AGENCY:                                                            PID#:  AD5849
SETTING CLASSIFICATION:  Concrete Sea Wall


The bench mark is set flush in the concrete sea wall west of the Hillsboro Inlet
Marina Building, 39.5 feet (12.0 m) south of the north boundary of the marina
property, 38.5 feet (11.7 m) south of Bench Mark NO 2 1973, and 4.0 feet (1.2 m)
south of the centerline of the pier.



                         BENCH MARK STAMPING:  P 314 1970

MONUMENTATION:           Survey Disk                               VM#:     5662
AGENCY:                                                            PID#:  AD2606
SETTING CLASSIFICATION:  Copper-clad Steel Rod


The bench mark is at the U.S. Coast Guard Station, 16 feet (5 m) NE of the NE
corner of the north wing of a one story white frame house, 13 feet (4 m) west of
the centerline of the Coast Guard Station Entrance, 4 feet (1 m) west of the
west gate post of the east-west fence along the Coast Guard Station, 0.6 foot
(0.2 m) south of the fence line, and 0.4 foot (0.1 m) south of a metal witness
post.  The bench mark is at ground level, crimped to a copper-clad steel rod
driven to a depth of 29 feet (9 m), and encased in a 4-inch metal pipe.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  6

                                                   PUBLICATION DATE:  10/26/1987
Station ID: 8722859                                SUPERCEDED DATE:   04/21/2003
Name:       HILLSBORO INLET MARINA, POMPANO BEACH, INTRACOASTA
            FLORIDA
NOAA Chart: 11466                                  Latitude:         26° 15.6' N
USGS Quad:  BOCA RATON                             Longitude:        80°  5.1' W


                         T I D A L   B E N C H   M A R K S


                         BENCH MARK STAMPING:  Y 311 1970

MONUMENTATION:           Survey Disk                               VM#:     5663
AGENCY:                                                            PID#:  AD2604
SETTING CLASSIFICATION:  Lighthouse Foundation


The bench mark is at the U.S. Coast Guard Station and light house, 168 feet (51
m) south of Bench Mark Z 311 1970, 14.6 feet (4.5 m) west of the SE leg of the
lighthouse, 10 feet (3 m) south of the SE corner of the steps leading up to the
lighthouse, and level with the ground.



                         BENCH MARK STAMPING:  Z 311 1970

MONUMENTATION:           Survey Disk                               VM#:     5664
AGENCY:                                                            PID#:  AD2605
SETTING CLASSIFICATION:  Concrete Flagpole Base


The bench mark is at the U.S. Coast Guard station and lighthouse, 64 feet (20 m)
east of the centerline of a driveway at the Coast Guard station entrance, 23
feet (7 m) SE of the SW corner of the radio house, 22 feet (7 m) SW of the SW
corner of the fence surrounding a radio tower, and level with the ground.



                         BENCH MARK STAMPING:  NO 2 1973

MONUMENTATION:           Survey Disk                               VM#:     5666
AGENCY:                                                            PID#:  AD5850
SETTING CLASSIFICATION:  Concrete Sea Wall


The bench mark is set flush in the concrete sea wall west of the Hillsboro Inlet
Marina Building, 34.5 feet (10.5 m) north of the centerline of the pier, and 1.0
foot (0.3 m) 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  6

                                                   PUBLICATION DATE:  10/26/1987
Station ID: 8722859                                SUPERCEDED DATE:   04/21/2003
Name:       HILLSBORO INLET MARINA, POMPANO BEACH, INTRACOASTA
            FLORIDA
NOAA Chart: 11466                                  Latitude:         26° 15.6' N
USGS Quad:  BOCA RATON                             Longitude:        80°  5.1' W


                         T I D A L   B E N C H   M A R K S


                         BENCH MARK STAMPING:  NO 3 1973

MONUMENTATION:           Survey Disk                               VM#:     5667
AGENCY:                                                            PID#:  AD5848
SETTING CLASSIFICATION:  Concrete Curbing


The bench mark is set flush in the concrete curbing near a drain, 220.0 feet
(67.1 m) south of the south end of State Highway A1A bridge over Hillsboro Inlet
and Bench Mark NO 4 1973, and 18.0 feet (5.5 m) west of the centerline of the
highway.



                         BENCH MARK STAMPING:  NO 4 1973

MONUMENTATION:           Survey Disk                               VM#:     5668
AGENCY:                                                            PID#:  AD5846
SETTING CLASSIFICATION:  Concrete Sidewalk


The bench mark is set flush in the concrete sidewalk on the south end of State
Highway A1A bridge over Hillsboro Inlet, 16.0 feet (4.9 m) west of the
centerline of the bridge, and 1.1 feet (0.3 m) west of the east edge of the
curb.



                         BENCH MARK STAMPING:  NO 5 1973

MONUMENTATION:           Survey Disk                               VM#:     5669
AGENCY:                                                            PID#:  AD5847
SETTING CLASSIFICATION:  Bridge Abutment


The bench mark is set flush in the concrete bridge abutment foundation under the
south end of State Highway A1A bridge over Hillsboro Inlet, 200.0 feet (61.0 m)
north of Bench Mark NO 4 1973, 34.5 feet (10.5 m) south of the concrete sea
wall, and 15.0 feet (4.6 m) south of the centerline of a paved road under the
bridge.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  6

                                                   PUBLICATION DATE:  10/26/1987
Station ID: 8722859                                SUPERCEDED DATE:   04/21/2003
Name:       HILLSBORO INLET MARINA, POMPANO BEACH, INTRACOASTA
            FLORIDA
NOAA Chart: 11466                                  Latitude:         26° 15.6' N
USGS Quad:  BOCA RATON                             Longitude:        80°  5.1' W


                         T I D A L   B E N C H   M A R K S


                         BENCH MARK STAMPING:  16.770

MONUMENTATION:           Survey Disk                               VM#:     5670
AGENCY:                                                            PID#:  AD2608
SETTING CLASSIFICATION:  Concrete Sidewalk


The bench mark is set in the SE concrete sidewalk of State Highway A1A bridge
over Hillsboro Inlet, 198 feet (60 m) NE of the SW end of the bridge, 15 feet (5
m) SE of the centerline of the highway, 1 foot (0.3 m) SE of the NW edge of the
sidewalk, and 1 foot (0.3 m) above the level of the bridge floor.



                         BENCH MARK STAMPING:  18.090

MONUMENTATION:           Survey Disk                               VM#:     5671
AGENCY:                                                            PID#:  AD2607
SETTING CLASSIFICATION:  Concrete Curb


The bench mark is set in the NW curb of the State Highway A1A Bridge, over
Hillsboro Inlet 15.6 feet (4.8 m) NW of the centerline of the highway, 6.9 feet
(2.1 m) SW of the NE end of the bannister, and 1 foot (0.3 m) above the level of
the highway.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  5 of  6

                                                   PUBLICATION DATE:  10/26/1987
Station ID: 8722859                                SUPERCEDED DATE:   04/21/2003
Name:       HILLSBORO INLET MARINA, POMPANO BEACH, INTRACOASTA
            FLORIDA
NOAA Chart: 11466                                  Latitude:         26° 15.6' N
USGS Quad:  BOCA RATON                             Longitude:        80°  5.1' W


                            T I D A L   D A T U M S 


Tidal datums at HILLSBORO INLET MARINA, POMPANO BEACH, INTRACOASTA based on:

     LENGTH OF SERIES:      6 MONTHS
     TIME PERIOD:           MAY-OCTOBER 1973
     TIDAL EPOCH:           1960-1978
     CONTROL TIDE STATION:  8723170 MIAMI BEACH


Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET:

     HIGHEST OBSERVED WATER LEVEL (10/25/1973)         =   4.43
     MEAN HIGHER HIGH WATER                     MHHW   =   2.74
     MEAN HIGH WATER                            MHW    =   2.61
     MEAN TIDE LEVEL                            MTL    =   1.38
   * NATIONAL GEODETIC VERTICAL DATUM           NGVD29 =   0.86
     MEAN LOW WATER                             MLW    =   0.16
     MEAN LOWER LOW WATER                       MLLW   =   0.00
     LOWEST  OBSERVED WATER LEVEL (06/01/1973)         =  -0.80

   * NGVD is based on elevation published in Quad 260802, 2/73 and NOS
     levelingof 1981. 
North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In FEET above:

     Stamping or Designation                    MLLW        MHW

     NO 1 1973                                   5.37      2.76
     P 314 1970                                 12.41      9.80
     Y 311 1970                                 12.05      9.44
     Z 311 1970                                 13.51     10.90
     NO 2 1973                                   5.43      2.82
     NO 3 1973                                   4.56      1.95
     NO 4 1973                                   8.14      5.53
     NO 5 1973                                   5.73      3.12
     16.770                                     17.57     14.96
     18.090                                     18.89     16.28


                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  6 of  6

                                                   PUBLICATION DATE:  10/26/1987
Station ID: 8722859                                SUPERCEDED DATE:   04/21/2003
Name:       HILLSBORO INLET MARINA, POMPANO BEACH, INTRACOASTA
            FLORIDA
NOAA Chart: 11466                                  Latitude:         26° 15.6' N
USGS Quad:  BOCA RATON                             Longitude:        80°  5.1' 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.

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