U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 5 Station ID: 8723814 PUBLICATION DATE: 10/31/2005 Name: UPPER MATECUMBE KEY,ATLAN. SIDE FL NOAA Chart: 11449 Latitude: 24° 54.9' N ( 24.91500) USGS Quad: UPPER MATECUMBE KEY Longitude: 80° 37.9' W ( -80.63170) To reach the tidal bench marks from the post office in Islamorada, proceed SW on U.S. Highway 1 for 1.8 km (1.1 mi) to the entrance of the Cheeca Lodge, go SE on the drive for 0.3 km (0.2 mi) to the lodge. The bench marks are located along U.S. Highway 1 and between U.S. Highway 1 and the end of the road. The tide gage and staff were located on the Cheeca Lodge fishing pier. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: NO 2 1975 DESIGNATION: 872 3814 TIDAL 2 MONUMENTATION: Tidal Station disk VM#: 10962 AGENCY: National Ocean Survey (NOS) IDB PID#: AA0838 SETTING CLASSIFICATION: Concrete step OPUS PID: LATITUDE: 24° 55.1' N ( 24.91830) LONGITUDE: 80° 38.1' W ( -80.63500) The primary bench mark is a disk set flush in the first concrete step of the stairway of the most northwestern two-story apartment building SW of the lodge, 82.42 m (270.4 ft) SSW of the base of a radio tower, 18 m (60 ft) SW of the centerline of the drive, 8 m (26 ft) SW of the north corner of the apartment building, 1.62 m (5.3 ft) NW of the NW side of the apartment building, and 0.3 m (1.0 ft) above ground level.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 5 Station ID: 8723814 PUBLICATION DATE: 10/31/2005 Name: UPPER MATECUMBE KEY,ATLAN. SIDE FL NOAA Chart: 11449 Latitude: 24° 54.9' N ( 24.91500) USGS Quad: UPPER MATECUMBE KEY Longitude: 80° 37.9' W ( -80.63170) T I D A L B E N C H M A R K S BENCH MARK STAMPING: NO 3 1975 DESIGNATION: 872 3814 TIDAL 3 MONUMENTATION: Tidal Station disk VM#: 10963 AGENCY: National Ocean Survey (NOS) IDB PID#: AA0839 SETTING CLASSIFICATION: Concrete step OPUS PID: LATITUDE: 24° 55.1' N ( 24.91830) LONGITUDE: 80° 38.1' W ( -80.63500) The bench mark is a disk set flush in the first concrete step of the stairway of the most southern two-story apartment building SW of the lodge, 30 m (100 ft) SSE of bench mark NO 2 1975, 18 m (59 ft) SW of the centerline of the drive, 8 m (26 ft) SW of the north corner of the apartment building, 1.62 m (5.3 ft) NW of the NW side of the apartment building, and 0.3 m (1.0 ft) above ground level.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 5 Station ID: 8723814 PUBLICATION DATE: 10/31/2005 Name: UPPER MATECUMBE KEY,ATLAN. SIDE FL NOAA Chart: 11449 Latitude: 24° 54.9' N ( 24.91500) USGS Quad: UPPER MATECUMBE KEY Longitude: 80° 37.9' W ( -80.63170) T I D A L B E N C H M A R K S BENCH MARK STAMPING: R 276 1966 DESIGNATION: R 276 ALIAS: 872 3814 TIDAL MONUMENTATION: Bench Mark disk VM#: 10964 AGENCY: US Coast and Geodetic Survey (USC&GS) IDB PID#: AA0422 SETTING CLASSIFICATION: Concrete wall OPUS PID: LATITUDE: 24° 55.1' N ( 24.91830) LONGITUDE: 80° 38.2' W ( -80.63670) The bench mark is a disk recessed 0.15 m (0.5 ft) in the NW concrete wall of a 1 m (4 ft) square concrete check valve box for the SE water tank at the Florida Keys Aqueduct Commission office, 2.3 km (1.4 mi) SW of the post office in Islamoranda, 29.72 m (97.5 ft) NW of the centerline of U.S. Highway 1, 8.38 m (27.5 ft) SW of the SW corner of a water tank, 3.54 m (11.6 ft) NW of the west corner of the office building, 0.3 m (1.0 ft) below U.S. Highway 1 and under a removable valve cover.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 5 Station ID: 8723814 PUBLICATION DATE: 10/31/2005 Name: UPPER MATECUMBE KEY,ATLAN. SIDE FL NOAA Chart: 11449 Latitude: 24° 54.9' N ( 24.91500) USGS Quad: UPPER MATECUMBE KEY Longitude: 80° 37.9' W ( -80.63170) T I D A L D A T U M S Tidal datums at UPPER MATECUMBE KEY,ATLAN. SIDE based on: LENGTH OF SERIES: 1 MONTH TIME PERIOD: June 1975 - June 1975 TIDAL EPOCH: 1983-2001 CONTROL TIDE STATION: 8724580 KEY WEST Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS: MEAN HIGHER HIGH WATER MHHW = 0.696 MEAN HIGH WATER MHW = 0.655 North American Vertical Datum NAVD88 = 0.616 MEAN SEA LEVEL MSL = 0.361 MEAN TIDE LEVEL MTL = 0.354 MEAN LOW WATER MLW = 0.053 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 2 1975 2.003 1.348 NO 3 1975 2.175 1.520 R 276 1966 3.070 2.415
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 5 Station ID: 8723814 PUBLICATION DATE: 10/31/2005 Name: UPPER MATECUMBE KEY,ATLAN. SIDE FL NOAA Chart: 11449 Latitude: 24° 54.9' N ( 24.91500) USGS Quad: UPPER MATECUMBE KEY Longitude: 80° 37.9' W ( -80.63170) 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.