U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 5 Station ID: 8725665 PUBLICATION DATE: 02/05/2004 Name: LITTLE GASPARILLA ISLAND FL NOAA Chart: 11426 Latitude: 26° 49.6' N ( 26.82670) USGS Quad: PLACIDA Longitude: 82° 17.1' W ( -82.28500) To reach the tidal bench marks, SW of Placida, proceed 1.6 km (1.0 mi) NW from the SE end of Little Gasparilla Island. The bench marks are located along a dirt road and near the water plant. The tide gage was located northwest along a dirt road from the water plant, on the dock leading from a two story pole dwelling with an addition to SW end. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: 5665 A 1977 DESIGNATION: 872 5665 A MONUMENTATION: Tidal Station disk VM#: 7374 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID: LATITUDE: 26° 49.6' N ( 26.82670) LONGITUDE: 82° 17.1' W ( -82.28500) The primary bench mark is a disk located northwest along a dirt road from the water plant, 26.52 m (87.0 ft) ENE of bench mark 5665 B 1977, 15.85 m (52.0 ft) SSE of the east corner of a two-story pole dwelling, 7.62 m (25.0 ft) SW of the water's edge. The bench mark is set 6 cm (0.2 ft) below ground level, crimped to the top of a copper-clad steel rod driven 9.8 m (32 ft), and encased in a PVC pipe with concrete kickblock.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 5 Station ID: 8725665 PUBLICATION DATE: 02/05/2004 Name: LITTLE GASPARILLA ISLAND FL NOAA Chart: 11426 Latitude: 26° 49.6' N ( 26.82670) USGS Quad: PLACIDA Longitude: 82° 17.1' W ( -82.28500) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 5665 B 1977 DESIGNATION: 872 5665 B MONUMENTATION: Tidal Station disk VM#: 7375 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID: LATITUDE: 26° 49.6' N ( 26.82670) LONGITUDE: 82° 17.1' W ( -82.28500) The bench mark is a disk located northwest along a dirt road from the water plant, 25.60 m (84.0 ft) ESE of bench mark 5665 C 1977, 8.53 m (28.0 ft) NE of a utility pole, 7.01 m (23.0 ft) SSE of the south corner of a two-story pole dwelling, 0.46 m (1.5 ft) NW of the utility pole guy wire, and 0.24 m (0.8 ft) north of a witness post. The bench mark is set at ground level, crimped to the top of a copper-clad steel rod driven 9.8 m (32 ft), and encased in a PVC pipe with concrete kickblock. BENCH MARK STAMPING: 5665 C 1977 DESIGNATION: 872 5665 C MONUMENTATION: Tidal Station disk VM#: 7376 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID: LATITUDE: 26° 49.6' N ( 26.82670) LONGITUDE: 82° 17.1' W ( -82.28500) TThe bench mark is a disk located northwest along a dirt road from the water plant, 61 m (200 ft) NE of bench mark 5665 E 1977, 22.25 m (73.0 ft) west of the west corner of the main structure of the two-story pole dwelling, 0.61 m (2.0 ft) SE of a utility pole with a witness sign, and 0.15 m (0.5 ft) SE of a witness post. The bench mark is 0.24 m (0.8 ft) above ground level, crimped to the top of a copper-clad steel rod driven 9.8 m (32 ft), and encased in a PVC pipe with concrete kickblock.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 5 Station ID: 8725665 PUBLICATION DATE: 02/05/2004 Name: LITTLE GASPARILLA ISLAND FL NOAA Chart: 11426 Latitude: 26° 49.6' N ( 26.82670) USGS Quad: PLACIDA Longitude: 82° 17.1' W ( -82.28500) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 5665 E 1977 DESIGNATION: 872 5665 E MONUMENTATION: Tidal Station disk VM#: 7377 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID: LATITUDE: 26° 49.6' N ( 26.82670) LONGITUDE: 82° 17.1' W ( -82.28500) The bench mark is a disk located 11.58 m (38.0 ft) ESE of the east corner of the water plant building, 11.28 m (37.0 ft) ESE of bench mark 5665 F 1977, 0.76 m (2.5 ft) NW of a utility pole with a witness sign attached, and 0.24 m (0.8 ft) NNW of a witness post. The bench mark is set at ground level, crimped to the top of a copper-clad steel rod driven 9.8 m (32 ft) and encased in a PVC pipe with concrete kickblock. BENCH MARK STAMPING: 5665 F 1977 DESIGNATION: 872 5665 F MONUMENTATION: Tidal Station disk VM#: 7378 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID: LATITUDE: 26° 49.6' N ( 26.82670) LONGITUDE: 82° 17.1' W ( -82.28500) The bench mark is a disk located at the waterplant, 11.89 m (39.0 ft) WNW of a witness sign attached to a utility pole, 1.01 m (3.3 ft) south of the east corner of the plant, 0.76 m (2.5 ft) SE of the SE face of the water plant building, 0.27 m (0.9 ft) NE of a 0.91 m (3.0 ft) square concrete entrance pad, and 0.27 m (0.9 ft) SE of a witness post. The bench mark is 9 cm (0.3 ft) above ground level, crimped to a copper-clad steel rod driven 7.3 m (24 ft) and encased in a PVC pipe with concrete kickblock.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 5 Station ID: 8725665 PUBLICATION DATE: 02/05/2004 Name: LITTLE GASPARILLA ISLAND FL NOAA Chart: 11426 Latitude: 26° 49.6' N ( 26.82670) USGS Quad: PLACIDA Longitude: 82° 17.1' W ( -82.28500) T I D A L D A T U M S Tidal datums at LITTLE GASPARILLA ISLAND based on: LENGTH OF SERIES: 3 MONTHS TIME PERIOD: December 1977 - February 1978 TIDAL EPOCH: 1983-2001 CONTROL TIDE STATION: 8725110 NAPLES, GULF OF MEXICO Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS: MEAN HIGHER HIGH WATER MHHW = 0.464 MEAN HIGH WATER MHW = 0.389 MEAN SEA LEVEL MSL = 0.258 MEAN TIDE LEVEL MTL = 0.251 MEAN LOW WATER MLW = 0.113 MEAN LOWER LOW WATER MLLW = 0.000 North American Vertical Datum (NAVD88) Bench Mark Elevation Information In METERS above: Stamping or Designation MLLW MHW 5665 A 1977 0.703 0.314 5665 B 1977 0.909 0.520 5665 C 1977 0.916 0.527 5665 E 1977 1.181 0.792 5665 F 1977 1.091 0.702
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 5 Station ID: 8725665 PUBLICATION DATE: 02/05/2004 Name: LITTLE GASPARILLA ISLAND FL NOAA Chart: 11426 Latitude: 26° 49.6' N ( 26.82670) USGS Quad: PLACIDA Longitude: 82° 17.1' W ( -82.28500) 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.