U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 5 Station ID: 8724975 PUBLICATION DATE: 11/13/2003 Name: BLACKWATER RIVER ENTRANCE FL NOAA Chart: 11429 Latitude: 25° 55.9' N ( 25.93170) USGS Quad: ROYAL PALM HAMMOCK Longitude: 81° 35.8' W ( -81.59670) To reach the tidal bench marks from Goodland proceed by boat in the southerly direction for about 4.0 km (2.5 statute mi) to the southern tip of Tripod Key and then continue NE for about 6 km (4 statute mi) to the entrance of Blackwater River. The bench marks are located on the east shore of the river, about 0.5 km (0.3 mi) north of the entrance. The tide gage and staff were located in the river west of bench mark 4975 A 1978, on a free standing structure about 5 m (15 ft) offshore. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: 4975 A 1978 DESIGNATION: 872 4975 A MONUMENTATION: Tidal Station disk VM#: 9748 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Galvanized steel rod OPUS PID: LATITUDE: 25° 55.9' N ( 25.93170) LONGITUDE: 81° 35.8' W ( -81.59670) The primary bench mark is a disk located 8 m (25 ft) west of a 0.24 m (0.8 ft) diameter mangrove tree, 7 m (23 ft) SSW of bench mark 4975 B 1978, 2 m (7 ft) east of the approximate high water line, and 0.34 m (1.1 ft) NW of a witness post. The bench mark is 24 cm (0.8 ft) above the ground, crimped to a galvanized steel rod driven 6.4 m (21 ft) to refusal, and encased by a 4-inch steel pipe.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 5 Station ID: 8724975 PUBLICATION DATE: 11/13/2003 Name: BLACKWATER RIVER ENTRANCE FL NOAA Chart: 11429 Latitude: 25° 55.9' N ( 25.93170) USGS Quad: ROYAL PALM HAMMOCK Longitude: 81° 35.8' W ( -81.59670) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 4975 B 1978 DESIGNATION: 872 4975 B MONUMENTATION: Tidal Station disk VM#: 9749 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Galvanized steel rod OPUS PID: LATITUDE: 25° 55.9' N ( 25.93170) LONGITUDE: 81° 35.8' W ( -81.59670) The bench mark is a disk located about 15 m (50 ft) WNW of a small creek, 10 m (33 ft) WSW of bench mark 4975 C 1978, 5 m (17 ft) east of the approximate high water line, and 0.37 m (1.2 ft) SW of a witness post. The bench mark is 24 cm (0.8 ft) above the ground, crimped to a galvanized steel rod driven 6.1 m (20 ft) to refusal, and encased by a 4-inch steel pipe. BENCH MARK STAMPING: 4975 C 1978 DESIGNATION: 872 4975 C MONUMENTATION: Tidal Station disk VM#: 9750 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Galvanized steel rod OPUS PID: LATITUDE: 25° 55.9' N ( 25.93170) LONGITUDE: 81° 35.8' W ( -81.59670) The bench mark is a disk located 15 m (50 ft) east of the approximate high water line, 10 m (33 ft) SE of bench mark 4975 D 1978, 6 m (20 ft) NW of a small creek, and 0.30 m (1.0 ft) NW of a witness post. The bench mark is 0.24 m (0.8 ft) above the ground, crimped to a galvanized steel rod driven 7.0 m (23 ft) to refusal, and encased by a 4-inch steel pipe.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 5 Station ID: 8724975 PUBLICATION DATE: 11/13/2003 Name: BLACKWATER RIVER ENTRANCE FL NOAA Chart: 11429 Latitude: 25° 55.9' N ( 25.93170) USGS Quad: ROYAL PALM HAMMOCK Longitude: 81° 35.8' W ( -81.59670) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 4975 D 1978 DESIGNATION: 872 4975 D MONUMENTATION: Tidal Station disk VM#: 9751 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Galvanized steel rod OPUS PID: LATITUDE: 25° 55.9' N ( 25.93170) LONGITUDE: 81° 35.8' W ( -81.59670) The bench mark is a disk located 27 m (90 ft) south of bench mark 4975 E 1978, 9 m (30 ft) east of the approximate high water line, and 0.24 m (0.8 ft) west of a new witness post. The bench mark is 0.18 m (0.6 ft) above the ground, crimped to a galvanized steel rod driven 11.0 m (36 ft) to refusal and encased by a 4-inch steel pipe. BENCH MARK STAMPING: 4975 E 1978 DESIGNATION: 872 4975 E MONUMENTATION: Tidal Station disk VM#: 9752 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Galvanized steel rod OPUS PID: LATITUDE: 25° 55.9' N ( 25.93170) LONGITUDE: 81° 35.8' W ( -81.59670) The bench mark is a disk located 6 m (20 ft) east of the approximate high water line, and 0.40 m (1.3 ft) WSW of a witness post. The bench mark is 0.15 m (0.5 ft) above the ground crimped to a galvanized steel rod driven 12.2 m (40 ft) to refusal, and encased by a 4-inch steel pipe.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 5 Station ID: 8724975 PUBLICATION DATE: 11/13/2003 Name: BLACKWATER RIVER ENTRANCE FL NOAA Chart: 11429 Latitude: 25° 55.9' N ( 25.93170) USGS Quad: ROYAL PALM HAMMOCK Longitude: 81° 35.8' W ( -81.59670) T I D A L D A T U M S Tidal datums at BLACKWATER RIVER ENTRANCE based on: LENGTH OF SERIES: 2 MONTHS TIME PERIOD: March 1978 - April 1978 TIDAL EPOCH: 1983-2001 CONTROL TIDE STATION: 8724967 MARCO ISLAND, CAXAMBAS PASS Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS: MEAN HIGHER HIGH WATER MHHW = 0.985 MEAN HIGH WATER MHW = 0.898 MEAN TIDE LEVEL MTL = 0.517 MEAN SEA LEVEL MSL = 0.497 MEAN LOW WATER MLW = 0.135 MEAN LOWER LOW WATER MLLW = 0.000 North American Vertical Datum (NAVD88) Bench Mark Elevation Information In METERS above: Stamping or Designation MLLW MHW 4975 A 1978 1.465 0.567 4975 B 1978 1.589 0.691 4975 C 1978 1.316 0.418 4975 D 1978 1.298 0.400 4975 E 1978 1.460 0.562
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 5 Station ID: 8724975 PUBLICATION DATE: 11/13/2003 Name: BLACKWATER RIVER ENTRANCE FL NOAA Chart: 11429 Latitude: 25° 55.9' N ( 25.93170) USGS Quad: ROYAL PALM HAMMOCK Longitude: 81° 35.8' W ( -81.59670) 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.