U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 5 Station ID: 8724422 PUBLICATION DATE: 02/05/2004 Name: SIMILAR SOUND FL NOAA Chart: 11445 Latitude: 24° 36.0' N ( 24.60000) USGS Quad: SADDLEBUNCH KEYS Longitude: 81° 37.3' W ( -81.62170) To reach the tidal bench marks from the NE end of the U.S. Highway 1 bridge over Channel No. 5, proceed by boat south for 1.3 km (0.8 statute mi) to the SW end of a small peninsula of Saddlebunch Keys on the east side of Similar Sound. The bench marks are located at the SW end of the peninsula. The tide gage and staff were located offshore of the end of the peninsula. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: NO 1 1974 DESIGNATION: 872 4422 TIDAL 1 MONUMENTATION: Tidal Station disk VM#: 9591 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Concrete monument OPUS PID: LATITUDE: 24° 36.0' N ( 24.60000) LONGITUDE: 81° 37.3' W ( -81.62170) The primary bench mark is a disk set in a concrete monument atop a copper-clad steel rod driven to refusal, 18.29 m (60.0 ft) east of the NW most point of the SW end of the peninsula, 9 m (30 ft) NE of the water line on a high sand berm, 0.18 m (0.6 ft) south of a witness post, and at ground level.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 5 Station ID: 8724422 PUBLICATION DATE: 02/05/2004 Name: SIMILAR SOUND FL NOAA Chart: 11445 Latitude: 24° 36.0' N ( 24.60000) USGS Quad: SADDLEBUNCH KEYS Longitude: 81° 37.3' W ( -81.62170) T I D A L B E N C H M A R K S BENCH MARK STAMPING: NO 2 1974 DESIGNATION: 872 4422 TIDAL 2 MONUMENTATION: Tidal Station disk VM#: 9592 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Concrete monument OPUS PID: LATITUDE: 24° 36.0' N ( 24.60000) LONGITUDE: 81° 37.3' W ( -81.62170) The bench mark is a disk set in a concrete monument atop a copper-clad steel rod driven to refusal, 38 m (124 ft) SE of the NW most point of the SW end of the peninsula, 21 m (70 ft) ESE of bench mark NO 1 1974, 3 m (11 ft) west of the east side of the sand berm, 9 m (30 ft) NE of the water line on a high sand berm, 0.18 m (0.6 ft) WSW of a witness post, and 0.06 m (0.2 ft) above ground level. BENCH MARK STAMPING: NO 3 1974 DESIGNATION: 872 4422 TIDAL 3 MONUMENTATION: Tidal Station disk VM#: 9593 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Concrete monument OPUS PID: LATITUDE: 24° 36.0' N ( 24.60000) LONGITUDE: 81° 37.3' W ( -81.62170) The bench mark is a disk set in a concrete monument atop a copper-clad steel rod driven to refusal, 14.54 m (47.7 ft) NE of bench mark NO 2 1974, 8 m (25 ft) east of the water line, 6 m (20 ft) east of the east side of the high sand berm, 0.24 m (0.8 ft) east of a witness post, and 0.06 m (0.2 ft) above ground level.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 5 Station ID: 8724422 PUBLICATION DATE: 02/05/2004 Name: SIMILAR SOUND FL NOAA Chart: 11445 Latitude: 24° 36.0' N ( 24.60000) USGS Quad: SADDLEBUNCH KEYS Longitude: 81° 37.3' W ( -81.62170) T I D A L B E N C H M A R K S BENCH MARK STAMPING: NO 4 1974 DESIGNATION: 872 4422 TIDAL 4 MONUMENTATION: Tidal Station disk VM#: 9594 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Concrete monument OPUS PID: LATITUDE: 24° 36.0' N ( 24.60000) LONGITUDE: 81° 37.3' W ( -81.62170) The bench mark is a disk set in a concrete monument atop a copper-clad steel rod driven to refusal, located 53 m (175 ft) NNW of the south side of the peninsula, 30 m (100 ft) SSE of the north side of the peninsula, 21 m (69 ft) SE of bench mark NO 3 1974, 0.24 m (0.8 ft) NE of a witness post, and 0.06 m (0.2 ft) above ground level. BENCH MARK STAMPING: NO 5 1974 DESIGNATION: 872 4422 TIDAL 5 MONUMENTATION: Tidal Station disk VM#: 9595 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Concrete monument OPUS PID: LATITUDE: 24° 36.0' N ( 24.60000) LONGITUDE: 81° 37.3' W ( -81.62170) The bench mark is a disk set in a concrete monument atop a copper-clad steel rod driven to refusal, on a high sand berm, 91 m (300 ft) ESE of the NW most point of the SW end of the peninsula, 41.70 m (136.8 ft) ENE of bench mark NO 4 1974, 9 m (29 ft) south of the water line on the north side of the peninsula, 0.30 m (1.0 ft) SSW of a witness post, and 0.24 m (0.8 ft) above ground level.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 5 Station ID: 8724422 PUBLICATION DATE: 02/05/2004 Name: SIMILAR SOUND FL NOAA Chart: 11445 Latitude: 24° 36.0' N ( 24.60000) USGS Quad: SADDLEBUNCH KEYS Longitude: 81° 37.3' W ( -81.62170) T I D A L D A T U M S Tidal datums at SIMILAR SOUND based on: LENGTH OF SERIES: 2 MONTHS TIME PERIOD: April 1974 - May 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: MEAN HIGHER HIGH WATER MHHW = 0.237 MEAN HIGH WATER MHW = 0.168 MEAN SEA LEVEL MSL = 0.098 MEAN TIDE LEVEL MTL = 0.091 MEAN LOW WATER MLW = 0.014 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 1974 0.566 0.398 NO 2 1974 0.718 0.550 NO 3 1974 0.284 0.116 NO 4 1974 0.143 -0.025 NO 5 1974 0.582 0.414
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 5 Station ID: 8724422 PUBLICATION DATE: 02/05/2004 Name: SIMILAR SOUND FL NOAA Chart: 11445 Latitude: 24° 36.0' N ( 24.60000) USGS Quad: SADDLEBUNCH KEYS Longitude: 81° 37.3' W ( -81.62170) 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.