U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 4 PUBLICATION DATE: 07/01/1986 Station ID: 8723350 SUPERCEDED DATE: 04/21/2003 Name: RAGGED KEY NO 3, BISCAYNE BAY FLORIDA NOAA Chart: 11462 Latitude: 25° 32.0' N USGS Quad: SOLDIER KEY Longitude: 80° 10.3' W To reach the tidal bench marks from Elliott Key Harbor, proceed by boat 4.7 miles (7.6 km) north to red day beacon 2, then 1.6 miles (2.6 km) NE passing on the north side of green day beacon 5 to Ragged Key No. 3. The bench marks are located on or within a circular seawall. The tide gage and staff were located on the SSW side of the seawall. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: NO 1 1971 MONUMENTATION: Survey Disk VM#: 5812 AGENCY: PID: SETTING CLASSIFICATION: Concrete Seawall The bench mark is set flush on top of a concrete seawall which encircles a two-story house and several small storage buildings, 162.0 feet (49.4 m) north of the SE corner of the seawall, 75.9 feet (23.1 m) ESE of the SE corner of the house, 69 feet (21 m) west of the east edge of the water line, and 15.9 feet (4.8 m) NE of a small cement storage building. BENCH MARK STAMPING: NO 2 1971 MONUMENTATION: Survey Disk VM#: 5813 AGENCY: PID: SETTING CLASSIFICATION: Concrete Seawall The bench mark is set flush in the concrete seawall, 71.2 feet (21.7 m) WNW of the NW corner of the two-story house, 53.0 feet (16.2 m) south of the NW corner of the seawall, and 47.0 feet (14.3 m) west of the SW corner of a small generator building.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 4 PUBLICATION DATE: 07/01/1986 Station ID: 8723350 SUPERCEDED DATE: 04/21/2003 Name: RAGGED KEY NO 3, BISCAYNE BAY FLORIDA NOAA Chart: 11462 Latitude: 25° 32.0' N USGS Quad: SOLDIER KEY Longitude: 80° 10.3' W T I D A L B E N C H M A R K S BENCH MARK STAMPING: NO 3 1971 MONUMENTATION: Survey Disk VM#: 5814 AGENCY: PID: SETTING CLASSIFICATION: Concrete Flagpole Base The bench mark is set flush in the fourth step of the concrete flagpole base, 80.4 feet (24.5 m) south of the south wall of the two-story house, 46.0 feet (14.0 m) north of a V in the seawall, and 22.4 feet (6.8 m) west of the west edge of the boat slip. BENCH MARK STAMPING: NO 4 1974 MONUMENTATION: Survey Disk VM#: 5815 AGENCY: PID: SETTING CLASSIFICATION: Concrete Seawall The bench mark is set flush in the SE corner of the concrete seawall, 155 feet (47 m) south of Bench Mark NO 1 1971, 99.5 feet (30.3 m) east of a boat slip, and 5.3 feet (1.6 m) north of the SE corner of the seawall. BENCH MARK STAMPING: NO STAMPING 1 MONUMENTATION: Compass Rose VM#: 5816 AGENCY: PID: SETTING CLASSIFICATION: Concrete Patio The bench mark is set flush in a concrete patio, 63.9 feet (19.5 m) SSW of Bench Mark NO 2 1971, 20.3 feet (6.2 m) SW of the corner of the two-story house, 19.6 feet (6.0 m) WSW of the west corner of the caretakers house, 18.3 feet (5.6 m) SW of the south corner of the generator building, and 17.3 feet (5.3 m) west of the cistern steps.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 4 PUBLICATION DATE: 07/01/1986 Station ID: 8723350 SUPERCEDED DATE: 04/21/2003 Name: RAGGED KEY NO 3, BISCAYNE BAY FLORIDA NOAA Chart: 11462 Latitude: 25° 32.0' N USGS Quad: SOLDIER KEY Longitude: 80° 10.3' W T I D A L D A T U M S Tidal datums at RAGGED KEY NO 3, BISCAYNE BAY based on: LENGTH OF SERIES: 12 MONTHS TIME PERIOD: JANUARY-DECEMBER 1975 TIDAL EPOCH: 1960-1978 CONTROL TIDE STATION: 8723170 MIAMI Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET: HIGHEST OBSERVED WATER LEVEL (10/06/1974) = 3.75 MEAN HIGHER HIGH WATER MHHW = 1.83 MEAN HIGH WATER MHW = 1.78 MEAN TIDE LEVEL MTL = 0.95 MEAN LOW WATER MLW = 0.13 MEAN LOWER LOW WATER MLLW = 0.00 LOWEST OBSERVED WATER LEVEL (04/05/1977) = -0.98 Bench Mark Elevation Information In FEET above: Stamping or Designation MLLW MHW NO 1 1971 5.36 3.58 NO 2 1971 5.12 3.34 NO 3 1971 6.62 4.84 NO 4 1974 5.36 3.58 NO STAMPING 1 4.97 3.19
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 4 PUBLICATION DATE: 07/01/1986 Station ID: 8723350 SUPERCEDED DATE: 04/21/2003 Name: RAGGED KEY NO 3, BISCAYNE BAY FLORIDA NOAA Chart: 11462 Latitude: 25° 32.0' N USGS Quad: SOLDIER KEY Longitude: 80° 10.3' 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.