U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 7 Station ID: 8722861 PUBLICATION DATE: 12/12/2003 Name: HILLSBORO INLET, INSIDE FL NOAA Chart: 11466 Latitude: 26° 15.5' N ( 26.25830) USGS Quad: BOCA RATON Longitude: 80° 4.9' W ( -80.08170) To reach the tidal bench marks from the intersection of State Highways A1A and 814 in Pompano Beach, proceed 3.78 km (2.35 mi) north on State Highway A1A to a black-topped road just north of the bridge over Hillsboro Inlet, then turn right and proceed 0.08 km (0.05 mi) east on the black-topped road to the entrance gate of the Hillsboro Inlet Private Club, then proceed 0.24 km (0.15 mi) past the gate to the U.S. Coast Guard Station. The bench marks are in the vicinity of the Coast Guard station. The tide gage was located at the south end of the Coast Guard Light Station pier. The tide staff was located on a piling about 5 m (15 ft) NE of the gage (the same staff was used for both stations 872 2861 and 872 2862). T I D A L B E N C H M A R K S
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 7 Station ID: 8722861 PUBLICATION DATE: 12/12/2003 Name: HILLSBORO INLET, INSIDE FL NOAA Chart: 11466 Latitude: 26° 15.5' N ( 26.25830) USGS Quad: BOCA RATON Longitude: 80° 4.9' W ( -80.08170) T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: Z 311 1970 DESIGNATION: Z 311 MONUMENTATION: Bench Mark disk VM#: 5674 AGENCY: National Geodetic Survey (NGS) IDB PID#: AD2605 SETTING CLASSIFICATION: Concrete flagpole base OPUS PID: LATITUDE: 26° 15.6' N ( 26.26000) LONGITUDE: 80° 4.8' W ( -80.08000) The primary bench mark is a disk set in the top of the SE corner of the concrete flagpole base located on the U.S. Coast Guard station, 20 m (64 ft) east of the centerline of the driveway, 7 m (23 ft) SE of the SW corner of the radio house, 7 m (22 ft) SW of the SW corner of the fence around the radio tower, and level with the ground.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 7 Station ID: 8722861 PUBLICATION DATE: 12/12/2003 Name: HILLSBORO INLET, INSIDE FL NOAA Chart: 11466 Latitude: 26° 15.5' N ( 26.25830) USGS Quad: BOCA RATON Longitude: 80° 4.9' W ( -80.08170) T I D A L B E N C H M A R K S BENCH MARK STAMPING: P 314 1970 DESIGNATION: P 314 MONUMENTATION: Bench Mark disk VM#: 5672 AGENCY: National Geodetic Survey (NGS) IDB PID#: AD2606 SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID: LATITUDE: 26° 15.6' N ( 26.26000) LONGITUDE: 80° 4.9' W ( -80.08170) The bench mark is a disk located along the east-west fence around the U.S. Coast Guard station, 5 m (16 ft) NE of the NE corner of the north wing of a 1-story frame house, 4 m (13 ft) west of the centerline of the driveway, 1 m (4 ft) west of the west face of the west gate post, 0.18 m (0.6 ft) south of the fence line, and 0.12 m (0.4 ft) south of a metal witness post. The bench mark is set level with the driveway, crimped to the top of a copper-clad steel rod driven 8.9 m (29.2 ft) to refusal, and encased in a metal pipe. Note: The bench mark was hit by heavy equipment and is severely bent. Use with caution.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 7 Station ID: 8722861 PUBLICATION DATE: 12/12/2003 Name: HILLSBORO INLET, INSIDE FL NOAA Chart: 11466 Latitude: 26° 15.5' N ( 26.25830) USGS Quad: BOCA RATON Longitude: 80° 4.9' W ( -80.08170) 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#: 5673 AGENCY: National Geodetic Survey (NGS) IDB PID#: AD2604 SETTING CLASSIFICATION: Concrete lighthouse base OPUS PID: LATITUDE: 26° 15.5' N ( 26.25830) LONGITUDE: 80° 4.8' W ( -80.08000) The bench mark is a disk set in the top of the east side of the concrete lighthouse base located at the U.S. Coast Guard station, 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, and 3 m (10 ft) south of the SE corner of the lighthouse steps. Note: The bench mark is covered by a thin layer of tar and gravel. BENCH MARK STAMPING: 16.770 DESIGNATION: 16.770 FLHD MONUMENTATION: Survey disk VM#: 5675 AGENCY: Florida Highway Department (FLHD) IDB PID#: AD2608 SETTING CLASSIFICATION: Sidewalk OPUS PID: LATITUDE: 26° 15.7' N ( 26.26170) LONGITUDE: 80° 5.0' W ( -80.08330) The bench mark is a disk set on the top of the sidewalk of the State Highway A1A bridge located over Hillsboro Inlet, 60 m (198 ft) NE of the SW end of the bridge, 5 m (15 ft) SE of the centerline of State Highway A1A, 0.3 m (1 ft) SE of the NW edge of the sidewalk, and 0.3 m (1 ft) above the bridge floor.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 7 Station ID: 8722861 PUBLICATION DATE: 12/12/2003 Name: HILLSBORO INLET, INSIDE FL NOAA Chart: 11466 Latitude: 26° 15.5' N ( 26.25830) USGS Quad: BOCA RATON Longitude: 80° 4.9' W ( -80.08170) 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#: 5676 AGENCY: Florida Highway Department (FLHD) IDB PID#: AD2607 SETTING CLASSIFICATION: 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 top of the NW curb of the State Highway A1A bridge located over Hillsboro Inlet, 4.75 m (15.6 ft) NW of the centerline of State Highway A1A, 2 m (7 ft) SW of the NE end of the bannister, and 0.3 m (1 ft) above road level.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 6 of 7 Station ID: 8722861 PUBLICATION DATE: 12/12/2003 Name: HILLSBORO INLET, INSIDE FL NOAA Chart: 11466 Latitude: 26° 15.5' N ( 26.25830) USGS Quad: BOCA RATON Longitude: 80° 4.9' W ( -80.08170) T I D A L D A T U M S Tidal datums at HILLSBORO INLET, INSIDE based on: LENGTH OF SERIES: 12 MONTHS TIME PERIOD: May 1970 - April 1971 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: HIGHEST OBSERVED WATER LEVEL (10/15/1970) = 1.169 MEAN HIGHER HIGH WATER MHHW = 0.849 MEAN HIGH WATER MHW = 0.807 North American Vertical Datum NAVD88 = 0.715 MEAN TIDE LEVEL MTL = 0.428 MEAN SEA LEVEL MSL = 0.426 MEAN LOW WATER MLW = 0.048 MEAN LOWER LOW WATER MLLW = 0.000 LOWEST OBSERVED WATER LEVEL (04/26/1971) = -0.342 North American Vertical Datum (NAVD88) Bench Mark Elevation Information In METERS above: Stamping or Designation MLLW MHW Z 311 1970 4.096 3.289 P 314 1970 3.761 2.954 Y 311 1970 3.654 2.847 16.770 5.336 4.529 18.090 5.736 4.929
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 7 of 7 Station ID: 8722861 PUBLICATION DATE: 12/12/2003 Name: HILLSBORO INLET, INSIDE FL NOAA Chart: 11466 Latitude: 26° 15.5' N ( 26.25830) USGS Quad: BOCA RATON Longitude: 80° 4.9' W ( -80.08170) 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.