U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 6 Station ID: 8724264 PUBLICATION DATE: 04/29/2004 Name: BIG TORCH KEY, WEST SIDE FL NOAA Chart: 11448 Latitude: 24° 42.3' N ( 24.70500) USGS Quad: SUMMERLAND KEY Longitude: 81° 26.0' W ( -81.43330) To reach the tidal bench marks from Summerland Key Post Office, proceed east on U.S. Highway 1 for 5.07 km (3.15 mi) to a paved road leading north on Middle Torch Key, then turn left and proceed north and west on the paved road for 3.9 km (2.4 mi) to the junction of a paved road leading to Big Torch Key, then turn and proceed west and north on the paved road for 3.7 km (2.3 mi) to the property of Stanley Hoke. The bench marks are located around a landfill and the paved road. The tide gage and staff were located offshore, west of the residence. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: NO 1 1973 DESIGNATION: 872 4264 TIDAL 1 MONUMENTATION: Tidal Station disk VM#: 6870 AGENCY: National Ocean Survey (NOS) IDB PID#: AA0720 SETTING CLASSIFICATION: Concrete monument OPUS PID: LATITUDE: 24° 42.4' N ( 24.70670) LONGITUDE: 81° 26.0' W ( -81.43330) The primary bench mark is a disk set flush in a concrete monument located at the NW corner of the landfill west of the Hoke residence, 2.35 m (7.7 ft) east of the west edge of the fill, 2.13 m (7.0 ft) south of the north edge of the fill, and at ground level.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 6 Station ID: 8724264 PUBLICATION DATE: 04/29/2004 Name: BIG TORCH KEY, WEST SIDE FL NOAA Chart: 11448 Latitude: 24° 42.3' N ( 24.70500) USGS Quad: SUMMERLAND KEY Longitude: 81° 26.0' W ( -81.43330) T I D A L B E N C H M A R K S BENCH MARK STAMPING: NO 2 1973 DESIGNATION: 872 4264 TIDAL 2 MONUMENTATION: Tidal Station disk VM#: 6871 AGENCY: National Ocean Survey (NOS) IDB PID#: AA0719 SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID: LATITUDE: 24° 42.4' N ( 24.70670) LONGITUDE: 81° 26.0' W ( -81.43330) The bench mark is a diskt located near the west edge of the landfill west of the residence, 15.54 m (51.0 ft) south of the north edge of the fill, 13.50 m (44.3 ft) south of bench mark NO 1 1973, and 3.54 m (11.6 ft) east of the west edge of the fill. The mark is set 6 cm (0.2 ft) above ground level, crimped to the top of a copper-clad steel rod, and is imbedded in a 0.30 m (0.98 ft) square concrete monument. BENCH MARK STAMPING: NO 3 1973 DESIGNATION: 872 4264 TIDAL 3 MONUMENTATION: Tidal Station disk VM#: 6872 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Mass of cement OPUS PID: LATITUDE: 24° 42.3' N ( 24.70500) LONGITUDE: 81° 26.0' W ( -81.43330) The bench mark is a disk set in cement on the west side of the key, 4.66 m (15.3 ft) east of the west edge of filled land, 2.13 m (7.0 ft) north of a canal on the south side of the filled land, and 9 cm (0.3 ft) above the land.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 6 Station ID: 8724264 PUBLICATION DATE: 04/29/2004 Name: BIG TORCH KEY, WEST SIDE FL NOAA Chart: 11448 Latitude: 24° 42.3' N ( 24.70500) USGS Quad: SUMMERLAND KEY Longitude: 81° 26.0' W ( -81.43330) T I D A L B E N C H M A R K S BENCH MARK STAMPING: NO 4 1973 DESIGNATION: 872 4264 TIDAL 4 MONUMENTATION: Tidal Station disk VM#: 6873 AGENCY: National Ocean Survey (NOS) IDB PID#: AA0718 SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID: LATITUDE: 24° 42.4' N ( 24.70670) LONGITUDE: 81° 26.0' W ( -81.43330) The bench mark is a disk located SW of the residence and north of a canal, 53.92 m (176.9 ft) east of the west end of the landfill, and 2.0 m (6.6 ft) north of the canal on the south side of the fill. The mark is set 6 cm (0.2 ft) above ground level, crimped to the top of a copper-clad steel rod, and is imbedded in a 0.30 m (0.98 ft) square concrete monument. BENCH MARK STAMPING: NO 5 1973 DESIGNATION: 872 4264 TIDAL 5 MONUMENTATION: Tidal Station disk VM#: 6874 AGENCY: National Ocean Survey (NOS) IDB PID#: AA0717 SETTING CLASSIFICATION: Concrete monument OPUS PID: LATITUDE: 24° 42.4' N ( 24.70670) LONGITUDE: 81° 25.9' W ( -81.43170) The bench mark is a disk set flush in a concrete monument located SW of the residence and north of the canal, 90 m (296 ft) east of the west edge of the landfill, 36.27 m (119.0 ft) east of bench mark NO 4 1973, 9.30 m (30.5 ft) south of the centerline of the Hoke driveway, 1.83 m (6.0 ft) north of the canal bank, and at ground level.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 6 Station ID: 8724264 PUBLICATION DATE: 04/29/2004 Name: BIG TORCH KEY, WEST SIDE FL NOAA Chart: 11448 Latitude: 24° 42.3' N ( 24.70500) USGS Quad: SUMMERLAND KEY Longitude: 81° 26.0' W ( -81.43330) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 4264 F 1982 DESIGNATION: 872 4264 F TIDAL MONUMENTATION: Tidal Station disk VM#: 6875 AGENCY: National Ocean Survey (NOS) IDB PID#: AA0716 SETTING CLASSIFICATION: Rock outcrop OPUS PID: LATITUDE: 24° 42.4' N ( 24.70670) LONGITUDE: 81° 25.7' W ( -81.42830) The bench mark is a disk located 0.2 km (0.1 mi) east of the entrance to the Hoke property, 50.14 m (164.5 ft) WNW of utility pole #MTK5-95-53, 22.95 m (75.3 ft) NE of utility pole #MTK5-95-54, 10.82 m (35.5 ft) north of the centerline of the paved road, and 1 m (3 ft) below road level.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 6 Station ID: 8724264 PUBLICATION DATE: 04/29/2004 Name: BIG TORCH KEY, WEST SIDE FL NOAA Chart: 11448 Latitude: 24° 42.3' N ( 24.70500) USGS Quad: SUMMERLAND KEY Longitude: 81° 26.0' W ( -81.43330) T I D A L D A T U M S Tidal datums at BIG TORCH KEY, WEST SIDE based on: LENGTH OF SERIES: 3 MONTHS TIME PERIOD: December 1973 - February 1974 TIDAL EPOCH: 1983-2001 CONTROL TIDE STATION: 8724211 BIG PINE KEY VIADUCT Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS: North American Vertical Datum NAVD88 = 0.389 MEAN HIGHER HIGH WATER MHHW = 0.360 MEAN HIGH WATER MHW = 0.278 MEAN SEA LEVEL MSL = 0.185 MEAN TIDE LEVEL MTL = 0.164 MEAN LOW WATER MLW = 0.050 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 1973 1.017 0.739 NO 2 1973 0.912 0.634 NO 3 1973 0.925 0.647 NO 4 1973 0.887 0.609 NO 5 1973 0.917 0.639 4264 F 1982 0.589 0.311
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 6 of 6 Station ID: 8724264 PUBLICATION DATE: 04/29/2004 Name: BIG TORCH KEY, WEST SIDE FL NOAA Chart: 11448 Latitude: 24° 42.3' N ( 24.70500) USGS Quad: SUMMERLAND KEY Longitude: 81° 26.0' W ( -81.43330) 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.