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.