U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 7 Station ID: 8723752 PUBLICATION DATE: 05/12/2004 Name: EAST KEY, FLORIDA BAY FL NOAA Chart: 11463 Latitude: 24° 59.8' N ( 24.99670) USGS Quad: PLANTATION KEY Longitude: 80° 36.6' W ( -80.61000) To reach the tidal bench marks from the Islamorada Coast Guard Station at Snake Creek on Plantation Key, proceed by boat NNW for 5.8 km (3.6 statute mi) to the SE side of East Key. The bench marks are located on the SE side of East Key. The tide gage and staff were located off the SE shore of East Key on a light structure. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: NO 1 1975 DESIGNATION: CRANE KEY NO 1 MONUMENTATION: Bench Mark disk VM#: 6021 AGENCY: National Ocean Survey (NOS) IDB PID#: AC4848 SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID: LATITUDE: 25° 0.2' N ( 25.00330) LONGITUDE: 80° 37.1' W ( -80.61830) The primary bench mark is a disk located 24 m (80 ft) NW of the shoreline, 1.98 m (6.5 ft) NW of a witness sign nailed to a buttonwood tree, and 0.34 m (1.1 ft) NW of a witness post, and 9 cm (0.3 ft) above the ground. The bench mark is set in concrete atop a copper-clad rod driven an unspecified depth to refusal.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 7 Station ID: 8723752 PUBLICATION DATE: 05/12/2004 Name: EAST KEY, FLORIDA BAY FL NOAA Chart: 11463 Latitude: 24° 59.8' N ( 24.99670) USGS Quad: PLANTATION KEY Longitude: 80° 36.6' W ( -80.61000) T I D A L B E N C H M A R K S BENCH MARK STAMPING: EAST 1859 NO 1 1934 DESIGNATION: EAST RM 1 MONUMENTATION: Reference Mark disk VM#: 6019 AGENCY: US Coast and Geodetic Survey (USC&GS) IDB PID#: AE9201 SETTING CLASSIFICATION: Concrete in pipe OPUS PID: LATITUDE: 24° 59.8' N ( 24.99670) LONGITUDE: 80° 36.6' W ( -80.61000) The bench mark is a disk set in a 6-inch diameter tile sewer pipe, 33.83 m (111.0 ft) ENE of reference mark EAST 1859 NO 2 1934, 21.55 m (70.7 ft) NE of bench mark EAST, and 0.24 m (0.8 ft) west of a witness post.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 7 Station ID: 8723752 PUBLICATION DATE: 05/12/2004 Name: EAST KEY, FLORIDA BAY FL NOAA Chart: 11463 Latitude: 24° 59.8' N ( 24.99670) USGS Quad: PLANTATION KEY Longitude: 80° 36.6' W ( -80.61000) T I D A L B E N C H M A R K S BENCH MARK STAMPING: EAST 1859 NO 2 1934 DESIGNATION: EAST RM 2 MONUMENTATION: Reference Mark disk VM#: 6020 AGENCY: US Coast and Geodetic Survey (USC&GS) IDB PID#: AE9202 SETTING CLASSIFICATION: Concrete in pipe OPUS PID: LATITUDE: 24° 59.8' N ( 24.99670) LONGITUDE: 80° 36.6' W ( -80.61000) The bench mark is a disk set in concrete in a 6-inch diameter tile sewer pipe, 21.66 m (71.1 ft) NW of bench mark EAST, 0.24 m (0.8 ft) east of a witness post, and 6 cm (0.2 ft) above the ground. BENCH MARK STAMPING: NO 2 1975 DESIGNATION: 872 3752 TIDAL 2 MONUMENTATION: Tidal Station disk VM#: 6022 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID: LATITUDE: 24° 59.8' N ( 24.99670) LONGITUDE: 80° 36.6' W ( -80.61000) The bench mark is a disk located 20.63 m (67.7 ft) NNW of bench mark NO 1 1975, 20 m (65 ft) SE of bench mark East 1859 NO 2 1934, 4 m (12 ft) NW of a witness sign on a buttonwood tree, and 0.24 m (0.8 ft) NW of a witness post. The bench mark is set 15 cm (0.5 ft) above ground level, crimped to a copper-clad rod driven an unspecified depth to refusal.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 7 Station ID: 8723752 PUBLICATION DATE: 05/12/2004 Name: EAST KEY, FLORIDA BAY FL NOAA Chart: 11463 Latitude: 24° 59.8' N ( 24.99670) USGS Quad: PLANTATION KEY Longitude: 80° 36.6' W ( -80.61000) T I D A L B E N C H M A R K S BENCH MARK STAMPING: DESIGNATION: EAST ALIAS: NO STAMPING 1 MONUMENTATION: Chiseled Cross VM#: 6023 AGENCY: US Coast and Geodetic Survey (USC&GS) IDB PID#: AA1322 SETTING CLASSIFICATION: Granite monument OPUS PID: LATITUDE: 24° 59.9' N ( 24.99830) LONGITUDE: 80° 36.6' W ( -80.61000) The bench mark is a granite monument with a faint cross cut in the top, on the SW side of East Key in an open ground inshore from the mangroves that grow close together along the shore, 21.55 m (70.7 ft) SW of reference mark EAST 1859 NO 1 1934, 17.77 m (58.3 ft) NW of bench mark NO 2 1975, and 0.18 m (0.6 ft) SE of a witness post.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 7 Station ID: 8723752 PUBLICATION DATE: 05/12/2004 Name: EAST KEY, FLORIDA BAY FL NOAA Chart: 11463 Latitude: 24° 59.8' N ( 24.99670) USGS Quad: PLANTATION KEY Longitude: 80° 36.6' W ( -80.61000) T I D A L B E N C H M A R K S BENCH MARK STAMPING: DESIGNATION: EAST RP NW ALIAS: NO STAMPING 2 MONUMENTATION: Chiseled Cross VM#: 6024 AGENCY: US Coast and Geodetic Survey (USC&GS) IDB PID#: AE9203 SETTING CLASSIFICATION: Granite monument OPUS PID: LATITUDE: 24° 59.8' N ( 24.99670) LONGITUDE: 80° 36.6' W ( -80.61000) The bench mark is a 9 cm (0.3 ft) square granite monument with a prominent cross cut in the top (designated as a reference mark for Triangulation Station EAST), in the middle of the SW side of East Key, and 1.95 m (6.4 ft) NNW of bench mark EAST, and 6 cm (0.2 ft) above the ground. NOTE: This is also referred to as the north granite monument.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 6 of 7 Station ID: 8723752 PUBLICATION DATE: 05/12/2004 Name: EAST KEY, FLORIDA BAY FL NOAA Chart: 11463 Latitude: 24° 59.8' N ( 24.99670) USGS Quad: PLANTATION KEY Longitude: 80° 36.6' W ( -80.61000) T I D A L D A T U M S Tidal datums at EAST KEY, FLORIDA BAY based on: LENGTH OF SERIES: 1 MONTH TIME PERIOD: June 1975 - June 1975 TIDAL EPOCH: 1983-2001 CONTROL TIDE STATION: 8723852 LOWER MATECUMBE KEY, FLA. BAY Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS: MEAN HIGHER HIGH WATER MHHW = 0.186 MEAN HIGH WATER MHW = 0.160 MEAN TIDE LEVEL MTL = 0.082 MEAN SEA LEVEL MSL = 0.079 MEAN LOW WATER MLW = 0.004 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 1975 0.306 0.146 EAST 1859 NO 1 1934 0.258 0.098 EAST 1859 NO 2 1934 0.299 0.139 NO 2 1975 0.349 0.189 EAST 0.315 0.155 EAST RP NW 0.299 0.139 Foot Notes: Bench mark East RP NW is based on one differential leveling connection and does not meet the quality control standards of the NOS. Therefore, caution should be used when deriving an elevation for this mark.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 7 of 7 Station ID: 8723752 PUBLICATION DATE: 05/12/2004 Name: EAST KEY, FLORIDA BAY FL NOAA Chart: 11463 Latitude: 24° 59.8' N ( 24.99670) USGS Quad: PLANTATION KEY Longitude: 80° 36.6' W ( -80.61000) 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.