U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 5 Station ID: 8723746 PUBLICATION DATE: 05/23/2003 Name: CRANE KEY FL NOAA Chart: 11452 Latitude: 25° 0.3' N ( 25.00500) USGS Quad: Tavernier Longitude: 80° 37.1' W ( -80.61830) To reach the tidal bench marks from the U.S. Highway 1 bridge over Snake Creek, Windley Key, proceed by boat 7.6 km (4.7 mi) NNW to the NW side of the largest of the Crane Keys. The bench marks are located in a clear area, 0.3 km (0.2 mi) NE of the SW end of Crane Key. The tide gage and staff were located off the NW shore of the largest Crane Key. 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 Tidal 1 MONUMENTATION: Bench Mark disk VM#: 5994 AGENCY: National Ocean Survey (NOS) IDB PID#: AC4848 SETTING CLASSIFICATION: Concrete monument OPUS PID: LATITUDE: 25° 0.3' N ( 25.00500) LONGITUDE: 80° 37.1' W ( -80.61830) The primary bench mark is a disk located on the edge of a tidal pond, 20.24 m (66.4 ft) NE of Bench Mark NO 2 1975, 10.85 m (35.6 ft) SE of the NW shoreline, and 0.24 m (0.8 ft) NW of a witness post. The bench mark is set 0.09 m (0.3 ft) above the ground, crimped to a copper-clad steel rod driven to refusal, and encased in concrete.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 5 Station ID: 8723746 PUBLICATION DATE: 05/23/2003 Name: CRANE KEY FL NOAA Chart: 11452 Latitude: 25° 0.3' N ( 25.00500) USGS Quad: Tavernier Longitude: 80° 37.1' W ( -80.61830) T I D A L B E N C H M A R K S BENCH MARK STAMPING: NO 2 1975 DESIGNATION: 872 3746 TIDAL 2 MONUMENTATION: Survey disk VM#: 5995 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Concrete monument OPUS PID: LATITUDE: 25° 0.3' N ( 25.00500) LONGITUDE: 80° 37.1' W ( -80.61830) The bench mark is a disk located on the edge of a tidal pond, 22 m (72 ft) NE of Bench Mark NO 4 1975, 20 m (66 ft) SW of Bench Mark NO 1 1975, 14.14 m (46.4 ft) NE of an Everglades National Park sign, and 0.24 m (0.8 ft) east of a witness post. The bench mark is set 0.06 m (0.2 ft) above the ground, crimped to a copper-clad steel rod driven to refusal, and encased in concrete. BENCH MARK STAMPING: NO 4 1975 DESIGNATION: 872 3746 TIDAL 4 MONUMENTATION: Survey disk VM#: 5996 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Concrete monument OPUS PID: LATITUDE: 25° 0.3' N ( 25.00500) LONGITUDE: 80° 37.1' W ( -80.61830) The bench mark is a disk located 21.76 m (71.4 ft) SW of Bench Mark NO 2 1975, 17.53 m (57.5 ft) NE of Bench Mark NO 5 1975, 8.35 m (27.4 ft) south of an Everglades National Park sign, and 0.24 m (0.8 ft) NW of a witness post. The bench mark is set 0.12 m (0.4 ft) above the ground, crimped to a copper-clad steel rod driven to refusal, and encased in concrete.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 5 Station ID: 8723746 PUBLICATION DATE: 05/23/2003 Name: CRANE KEY FL NOAA Chart: 11452 Latitude: 25° 0.3' N ( 25.00500) USGS Quad: Tavernier Longitude: 80° 37.1' W ( -80.61830) T I D A L B E N C H M A R K S BENCH MARK STAMPING: NO 5 1975 DESIGNATION: 872 3746 TIDAL 5 MONUMENTATION: Survey disk VM#: 5997 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Concrete monument OPUS PID: LATITUDE: 25° 0.3' N ( 25.00500) LONGITUDE: 80° 37.1' W ( -80.61830) The bench mark is a disk located 25 m (82 ft) SSW of an Everglades National Park sign, 17.53 m (57.5 ft) SW of Bench Mark NO 4 1975, and 0.40 m (1.3 ft) NW of a witness post. The bench mark is set 0.06 m (0.2 ft) above the ground, crimped to a copper-clad steel rod driven to refusal, and encased in concrete. BENCH MARK STAMPING: 3746 F 1984 DESIGNATION: 872 3746 F MONUMENTATION: Survey disk VM#: 5998 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Stainless steel rod OPUS PID: LATITUDE: 25° 0.3' N ( 25.00500) LONGITUDE: 80° 37.1' W ( -80.61830) The bench mark is a disk located on the edge of a tidal pond, 30.11 m (98.8 ft) ESE of an Everglades National Park sign, 29.23 m (95.9 ft) south of Bench Mark NO 1 1975, 23.96 m (78.6 ft) SE of Bench Mark NO 2 1975, and 4 m (12 ft) north of a witness post. The bench mark is set 0.06 m (0.2 ft) above the ground, crimped to a stainless steel rod driven 5 m (16 ft) to refusal, and encased in a PVC pipe and concrete kickblock.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 5 Station ID: 8723746 PUBLICATION DATE: 05/23/2003 Name: CRANE KEY FL NOAA Chart: 11452 Latitude: 25° 0.3' N ( 25.00500) USGS Quad: Tavernier Longitude: 80° 37.1' W ( -80.61830) T I D A L D A T U M S Tidal datums at CRANE KEY 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 = 0.152 MEAN HIGH WATER MHW = 0.128 MEAN TIDE LEVEL MTL = 0.068 MEAN SEA LEVEL MSL = 0.062 MEAN LOW WATER MLW = 0.008 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 0.238 0.110 NO 2 1975 0.237 0.109 NO 4 1975 0.358 0.230 NO 5 1975 0.359 0.231 3746 F 1984 0.233 0.105
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 5 Station ID: 8723746 PUBLICATION DATE: 05/23/2003 Name: CRANE KEY FL NOAA Chart: 11452 Latitude: 25° 0.3' N ( 25.00500) USGS Quad: Tavernier Longitude: 80° 37.1' W ( -80.61830) 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.