U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 5 PUBLICATION DATE: 05/02/1986 Station ID: 8724529 SUPERCEDED DATE: 04/21/2003 Name: KEY WEST, RIVIERA CANAL FLORIDA NOAA Chart: 11441 Latitude: 24° 33.8' N USGS Quad: KEY WEST Longitude: 81° 45.1' W To reach the tidal bench marks from the intersection of U.S. Highway 1 and State Highway A1A on the east side of Key West, proceed SE on State Highway A1A for 0.35 mile (0.56 km) to the bridge over the Riviera Canal. The bench marks are located along State Highway A1A in the vicinity of the bridge. The tide gage and staff were located on a private dock SW of the NW corner of the bridge. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: NO 1 1974 MONUMENTATION: Survey Disk VM#: 10985 AGENCY: PID#: AA1004 SETTING CLASSIFICATION: Concrete Sidewalk The bench mark is set flush in the concrete sidewalk at the NE corner of the State Highway A1A bridge over Riviera Canal, 332 feet (101 m) SSE of Bench Mark P 121 1945, 33 feet (10 m) NNW of the SE corner of the bridge bannister, and 31 feet (9 m) ENE of the centerline of the highway. BENCH MARK STAMPING: NO 2 1974 MONUMENTATION: Survey Disk VM#: 10986 AGENCY: PID#: AA1003 SETTING CLASSIFICATION: Concrete Wingwall The bench mark is set flush in the SE concrete wingwall of the State Highway A1A bridge over Riviera Canal, 184 feet (56 m) SSE of Bench Mark NO 1 1974, 149 feet (45 m) NNW of the south end of the east bannister, 140 feet (43 m) NNE of Bench Mark B 271 1966, 35 feet (11 m) ENE of the centerline of the highway, and 1 foot (0.3 m) below the highway.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 5 PUBLICATION DATE: 05/02/1986 Station ID: 8724529 SUPERCEDED DATE: 04/21/2003 Name: KEY WEST, RIVIERA CANAL FLORIDA NOAA Chart: 11441 Latitude: 24° 33.8' N USGS Quad: KEY WEST Longitude: 81° 45.1' W T I D A L B E N C H M A R K S BENCH MARK STAMPING: NO 3 1974 MONUMENTATION: Survey Disk VM#: 10987 AGENCY: PID#: AA1002 SETTING CLASSIFICATION: Concrete Wingwall The bench mark is set flush in the SW concrete wingwall of the State Highway A1A over Riviera Canal, 40 feet (12 m) WSW of the centerline of the highway, 1 foot (0.3 m) east of the NW corner of the wingwall, and 3 feet (1 m) below the highway. BENCH MARK STAMPING: B 271 1966 MONUMENTATION: Survey Disk VM#: 10988 AGENCY: PID#: AA0051 SETTING CLASSIFICATION: Concrete Bannister The bench mark is set on top of the SE concrete bannister of the State Highway A1A bridge over Riviera Canal, 9.0 feet (2.7 m) NW of the SE end of the bannister, 6.9 feet (2.1 m) NE of the NE curb of the highway, and 3.5 feet (1.1 m) above sidewalk level. BENCH MARK STAMPING: P 121 1945 MONUMENTATION: Survey Disk VM#: 10989 AGENCY: PID#: AA0052 SETTING CLASSIFICATION: Concrete Seawall The bench mark is set on top of a concrete seawall at the intersection of Flagler Avenue and Roosevelt Boulevard (State Highway A1A) near the south corner of the U.S. Naval Hospital, 45 feet (14 m) SE of the extended centerline of Flagler Avenue, 41 feet (12 m) NW of the NW end of the NE concrete bannister of the bridge over Riviera Canal, 9.5 feet (2.9 m) NE of the NE curb of State Highway A1A, 1.1 feet (0.3 m) SW of a steel fence around the hospital grounds, and 1.5 feet (0.5 m) above sidewalk level. Note: mark is severely rusted.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 5 PUBLICATION DATE: 05/02/1986 Station ID: 8724529 SUPERCEDED DATE: 04/21/2003 Name: KEY WEST, RIVIERA CANAL FLORIDA NOAA Chart: 11441 Latitude: 24° 33.8' N USGS Quad: KEY WEST Longitude: 81° 45.1' W T I D A L B E N C H M A R K S BENCH MARK STAMPING: 4529 F 1982 MONUMENTATION: Survey Disk VM#: 10990 AGENCY: PID#: AA1005 SETTING CLASSIFICATION: Concrete Guard Rail Base The bench mark is set in the concrete guard rail base at the north end of the east bannister of the State Highway A1A bridge over Riviera Canal, 285.6 feet (87.1 m) NNW of the north abutment of the bridge, 33.4 feet (10.2 m) ENE of the centerline of the highway, 4.5 feet (1.4 m) SSE of the north end of the bannister, and 1 foot (0.3 m) above highway level.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 5 PUBLICATION DATE: 05/02/1986 Station ID: 8724529 SUPERCEDED DATE: 04/21/2003 Name: KEY WEST, RIVIERA CANAL FLORIDA NOAA Chart: 11441 Latitude: 24° 33.8' N USGS Quad: KEY WEST Longitude: 81° 45.1' W T I D A L D A T U M S Tidal datums at KEY WEST, RIVIERA CANAL based on: LENGTH OF SERIES: 2 MONTHS TIME PERIOD: NOVEMBER-DECEMBER 1974 TIDAL EPOCH: 1960-1978 CONTROL TIDE STATION: 8724211 BIG PINE KEY VIADUCT Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET: HIGHEST OBSERVED WATER LEVEL (10/16/1974) = 2.26 MEAN HIGHER HIGH WATER MHHW = 1.29 MEAN HIGH WATER MHW = 1.02 MEAN TIDE LEVEL MTL = 0.59 * NATIONAL GEODETIC VERTICAL DATUM NGVD29 = 0.23 MEAN LOW WATER MLW = 0.15 MEAN LOWER LOW WATER MLLW = 0.00 LOWEST OBSERVED WATER LEVEL (12/27/1974) = -0.46 * NGVD reference based on adjustment of 1971 and NOS levels of 1982. North American Vertical Datum (NAVD88) Bench Mark Elevation Information In FEET above: Stamping or Designation MLLW MHW NO 1 1974 12.37 11.35 NO 2 1974 10.80 9.78 NO 3 1974 7.23 6.21 B 271 1966 10.58 9.56 P 121 1945 5.33 4.31 4529 F 1982 5.35 4.33
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 5 PUBLICATION DATE: 05/02/1986 Station ID: 8724529 SUPERCEDED DATE: 04/21/2003 Name: KEY WEST, RIVIERA CANAL FLORIDA NOAA Chart: 11441 Latitude: 24° 33.8' N USGS Quad: KEY WEST Longitude: 81° 45.1' 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.