U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 5 Station ID: 8724963 PUBLICATION DATE: 04/25/2012 Name: DISMAL KEY, PUMPKIN BAY FL NOAA Chart: 11429 Latitude: 25° 53.7' N ( 25.89500) USGS Quad: PANTHER KEY Longitude: 81° 33.5' W ( -81.55830) To reach the tidal bench marks proceed to the NW side of Dismal Key. The bench marks are located along the trail leading around the island. The tide gage and staff were located on a dock. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: 4963 A 1978 DESIGNATION: 872 4963 A TIDAL MONUMENTATION: Tidal Station disk VM#: 10975 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Galvanized steel rod OPUS PID: LATITUDE: 25° 53.7' N ( 25.89500) LONGITUDE: 81° 33.5' W ( -81.55830) The primary bench mark is a disk located 8.50 m (27.9 ft) SE of the shoreline, 7.56 m (24.8 ft) WSW of the SW corner of a wooden shed, 5.09 m (16.7 ft) south of the SW shoreward end of a wooden dock, and 0.12 m (0.4 ft) ENE of a witness post. The bench mark is set 0.03 m (0.1 ft) below ground level, crimped to the top of a galvanized steel rod driven 10 m (32 ft) to refusal, encased in a steel protector pipe extending 0.34 m (1.1 ft) above the ground, and a concrete kickblock.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 5 Station ID: 8724963 PUBLICATION DATE: 04/25/2012 Name: DISMAL KEY, PUMPKIN BAY FL NOAA Chart: 11429 Latitude: 25° 53.7' N ( 25.89500) USGS Quad: PANTHER KEY Longitude: 81° 33.5' W ( -81.55830) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 4963 B 1978 DESIGNATION: 872 4963 B TIDAL MONUMENTATION: Tidal Station disk VM#: 10976 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Galvanized steel rod OPUS PID: LATITUDE: 25° 53.7' N ( 25.89500) LONGITUDE: 81° 33.5' W ( -81.55830) The bench mark is a disk located 38.65 m (126.8 ft) SSE of bench mark 4963 A 1978, 2.77 m (9.1 ft) WSW of the centerline of a path leading SE to a wooden house, 1.58 m (5.2 ft) west of the north corner of a cistern, and 0.15 m (0.5 ft) NE of a witness post. The bench mark is set 0.03 m (0.1 ft) below ground level, crimped to the top of a galvanized steel rod driven 10 m (32 ft) to refusal, encased in a steel protector pipe extending 0.34 m (1.1 ft) above the ground, and a concrete kickblock. BENCH MARK STAMPING: 4963 C 1978 DESIGNATION: 872 4963 C TIDAL MONUMENTATION: Tidal Station disk VM#: 10977 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Galvanized steel rod OPUS PID: LATITUDE: 25° 53.7' N ( 25.89500) LONGITUDE: 81° 33.5' W ( -81.55830) The bench mark is a disk located 51.21 m (168.0 ft) NE of bench mark 4963 D 1978, 2.13 m (7.0 ft) SE of the centerline of the trail, and 0.12 m (0.4 ft) east of a witness post. The bench mark is set 0.9 m (0.3 ft) above ground level, crimped to the top of a galvanized steel rod driven 10 m (32 ft) to refusal, encased in a steel protector pipe extending 0.46 m (1.5 ft) above the ground, and a concrete kickblock.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 5 Station ID: 8724963 PUBLICATION DATE: 04/25/2012 Name: DISMAL KEY, PUMPKIN BAY FL NOAA Chart: 11429 Latitude: 25° 53.7' N ( 25.89500) USGS Quad: PANTHER KEY Longitude: 81° 33.5' W ( -81.55830) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 4963 D 1978 DESIGNATION: 872 4963 D TIDAL MONUMENTATION: Tidal Station disk VM#: 10978 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Galvanized steel rod OPUS PID: LATITUDE: 25° 53.7' N ( 25.89500) LONGITUDE: 81° 33.5' W ( -81.55830) The bench mark is a disk located 21.31 m (69.9 ft) east of bench mark 4963 E 1978, 8.84 m (29.0 ft) south of the centerline of the trail, and 0.15 m (0.5 ft) east of a witness post. The bench mark is set 0.09 m (0.3 ft) above ground level, crimped to the top of a galvanized steel rod driven 10 m (32 ft) to refusal, encased in a steel protector pipe extending 0.18 m (0.6 ft) above the ground, and a concrete kickblock. BENCH MARK STAMPING: 4963 E 1978 DESIGNATION: 872 4963 E TIDAL MONUMENTATION: Tidal Station disk VM#: 10979 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Galvanized steel rod OPUS PID: LATITUDE: 25° 53.7' N ( 25.89500) LONGITUDE: 81° 33.5' W ( -81.55830) The bench mark is a disk located 5 m (16 ft) west of a 12-inch diameter mangrove, 4.42 m (14.5 ft) south of the centerline of the trail, and 0.24 m (0.8 ft) north of a witness post. The bench mark is set 0.09 m (0.3 ft) above ground level, crimped to the top of a galvanized steel rod driven 12 m (40 ft) to refusal, encased in a steel protector pipe extending 0.24 m (0.8 ft) above the ground, and a concrete kickblock.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 5 Station ID: 8724963 PUBLICATION DATE: 04/25/2012 Name: DISMAL KEY, PUMPKIN BAY FL NOAA Chart: 11429 Latitude: 25° 53.7' N ( 25.89500) USGS Quad: PANTHER KEY Longitude: 81° 33.5' W ( -81.55830) T I D A L D A T U M S Tidal datums at DISMAL KEY, PUMPKIN BAY based on: LENGTH OF SERIES: 3 MONTHS TIME PERIOD: March 1978 - May 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 = 1.150 MEAN HIGH WATER MHW = 1.060 MEAN SEA LEVEL MSL = 0.623 MEAN TIDE LEVEL MTL = 0.620 MEAN LOW WATER MLW = 0.181 MEAN LOWER LOW WATER MLLW = 0.000 North American Vertical Datum (NAVD88) Bench Mark Elevation Information In METERS above: Stamping or Designation MLLW MHW 4963 A 1978 1.311 0.251 4963 B 1978 2.600 1.540 4963 C 1978 2.194 1.134 4963 D 1978 1.732 0.672 4963 E 1978 2.157 1.097
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 5 Station ID: 8724963 PUBLICATION DATE: 04/25/2012 Name: DISMAL KEY, PUMPKIN BAY FL NOAA Chart: 11429 Latitude: 25° 53.7' N ( 25.89500) USGS Quad: PANTHER KEY Longitude: 81° 33.5' W ( -81.55830) 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.