U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 6 Station ID: 8723372 PUBLICATION DATE: 02/26/2004 Name: SANDS KEY, ELLIOTT KEY FL NOAA Chart: 11462 Latitude: 25° 30.4' N ( 25.50670) USGS Quad: SOLDIER KEY Longitude: 80° 11.3' W ( -80.18830) To reach the tidal bench marks from Elliott Key Harbor by boat, proceed NNE 5.5 km (3.4 statute mi) to the west side of Sands Key. The bench marks are on the west side of Sands Key. The tide gage and staff were located off the west northermost point. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: NO 3 1974 DESIGNATION: 872 3372 TIDAL 3 MONUMENTATION: Tidal Station disk VM#: 5822 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Rock outcrop OPUS PID: LATITUDE: 25° 30.3' N ( 25.50500) LONGITUDE: 80° 11.3' W ( -80.18830) The primary bench mark is a disk set flush in outcropping rock, 52 m (170 ft) south of bench mark SANDS POINT USED NO 2, 26 m (85 ft) SSW of bench mark NO 4 1974, 11 m (35 ft) east of the shoreline, and 0.43 m (1.4 ft) west of a witness post. BENCH MARK STAMPING: NO 4 1974 DESIGNATION: 872 3372 TIDAL 4 MONUMENTATION: Tidal Station disk VM#: 5823 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Outcropping coral rock OPUS PID: LATITUDE: 25° 30.3' N ( 25.50500) LONGITUDE: 80° 11.3' W ( -80.18830) The bench mark is a disk set flush in outcropping coral rock, 24.69 m (81.0 ft) SSW of bench mark SANDS POINT USED NO 2, 8 m (28 ft) east of the shoreline, 2 m (7 ft) north of a witness sign nailed to a tree, 1.68 m (5.5 ft) NW of a witness post, and 0.73 m (2.4 ft) west of a witness sign nailed to a tree.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 6 Station ID: 8723372 PUBLICATION DATE: 02/26/2004 Name: SANDS KEY, ELLIOTT KEY FL NOAA Chart: 11462 Latitude: 25° 30.4' N ( 25.50670) USGS Quad: SOLDIER KEY Longitude: 80° 11.3' W ( -80.18830) T I D A L B E N C H M A R K S BENCH MARK STAMPING: SANDS POINT USED NO 1 DESIGNATION: SANDS POINT RM 1 MONUMENTATION: Survey disk VM#: 5824 AGENCY: US Coast and Geodetic Survey (USC&GS) IDB PID#: AC3680 SETTING CLASSIFICATION: Outcropping bedrock OPUS PID: LATITUDE: 25° 30.4' N ( 25.50670) LONGITUDE: 80° 11.3' W ( -80.18830) The bench mark is a disk set in a drill hole in an outcropping bedrock located on the NW side of Sands Key, north of the overhanging mangroves at the shoreline, and east of the coral rock shoreline, 4 m (14 ft) SSE of a rock ledge dropoff, 3 m (9 ft) SE of the high-tide mark, and 0.49 m (1.6 ft) north of a witness sign.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 6 Station ID: 8723372 PUBLICATION DATE: 02/26/2004 Name: SANDS KEY, ELLIOTT KEY FL NOAA Chart: 11462 Latitude: 25° 30.4' N ( 25.50670) USGS Quad: SOLDIER KEY Longitude: 80° 11.3' W ( -80.18830) T I D A L B E N C H M A R K S BENCH MARK STAMPING: SANDS POINT USED NO 2 DESIGNATION: SANDS POINT RM 2 MONUMENTATION: Reference Mark disk VM#: 5825 AGENCY: US Coast and Geodetic Survey (USC&GS) IDB PID#: AC8611 SETTING CLASSIFICATION: Outcropping bedrock OPUS PID: LATITUDE: 25° 30.3' N ( 25.50500) LONGITUDE: 80° 11.3' W ( -80.18830) The bench mark is a disk set in outcropping bedrock located near the coral rock shoreline, 5 m (15 ft) SSE of a rock ledge dropoff, 4 m (13 ft) east of the high-tide mark, and 2.44 m (8.0 ft) NNW of a witness post.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 6 Station ID: 8723372 PUBLICATION DATE: 02/26/2004 Name: SANDS KEY, ELLIOTT KEY FL NOAA Chart: 11462 Latitude: 25° 30.4' N ( 25.50670) USGS Quad: SOLDIER KEY Longitude: 80° 11.3' W ( -80.18830) T I D A L B E N C H M A R K S BENCH MARK STAMPING: DESIGNATION: SANDS POINT ALIAS: NO STAMPING 1 MONUMENTATION: Clay Tile Pipe VM#: 5826 AGENCY: US Coast and Geodetic Survey (USC&GS) IDB PID#: AC3679 SETTING CLASSIFICATION: Terra cotta pipe in coral rock OPUS PID: LATITUDE: 25° 30.4' N ( 25.50670) LONGITUDE: 80° 11.3' W ( -80.18830) The bench mark is an iron pin set inside a terra cotta pipe cemented in coral, 14.63 m (48.0 ft) NNE of bench mark SANDS POINT USED NO 2, 10.85 m (35.6 ft) west of bench mark SANDS POINT USED NO 1, 4.15 m (13.6 ft) NW of a witness post, and 0.30 m (1.0 ft) SSE of a rock ledge dropoff. The bench mark is midway of a rock ledge on the NW tangent of the prominent NW point of Sands Key.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 6 Station ID: 8723372 PUBLICATION DATE: 02/26/2004 Name: SANDS KEY, ELLIOTT KEY FL NOAA Chart: 11462 Latitude: 25° 30.4' N ( 25.50670) USGS Quad: SOLDIER KEY Longitude: 80° 11.3' W ( -80.18830) T I D A L D A T U M S Tidal datums at SANDS KEY, ELLIOTT KEY based on: LENGTH OF SERIES: 1 MONTH TIME PERIOD: July 1974 - July 1974 TIDAL EPOCH: 1983-2001 CONTROL TIDE STATION: 8723350 RAGGED KEY #3 Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS: MEAN HIGHER HIGH WATER MHHW = 0.498 MEAN HIGH WATER MHW = 0.478 MEAN TIDE LEVEL MTL = 0.256 MEAN SEA LEVEL MSL = 0.244 MEAN LOW WATER MLW = 0.034 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 3 1974 1.048 0.570 NO 4 1974 0.905 0.427 SANDS POINT USED NO 1 0.561 0.083 SANDS POINT USED NO 2 0.744 0.266 SANDS POINT 0.498 0.020
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 6 of 6 Station ID: 8723372 PUBLICATION DATE: 02/26/2004 Name: SANDS KEY, ELLIOTT KEY FL NOAA Chart: 11462 Latitude: 25° 30.4' N ( 25.50670) USGS Quad: SOLDIER KEY Longitude: 80° 11.3' W ( -80.18830) 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.