U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 5 Station ID: 8665002 PUBLICATION DATE: 05/06/2003 Name: DRAYTON, BEES FERRY, ASHLEY RIVER SC NOAA Chart: 11524 Latitude: 32° 50.9' N ( 32.84830) USGS Quad: JOHNS ISLAND Longitude: 80° 3.1' W ( -80.05170) To reach the tidal bench marks from the intersection of State Highways 61 and 7, proceed NW on State Highway 61 for 6.1 km (3.8 mi) to North Lander Lane (entrance to Drayton-on-the-Ashley Housing Development), turn right and go NE for one block to Limestone Boulevard, turn right and go SE for one block to Brevard Street, turn left onto Brevard Street and continue to its end at Ashley River. The bench marks are located across a small slough SE from the dock and along the railroad. The tide gage and staff were at the NW end of the dock owned by Drayton Athletic Association. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: NO 1 1933 DESIGNATION: 866 5002 TIDAL 1 MONUMENTATION: Tidal Station disk VM#: 4130 AGENCY: US Coast and Geodetic Survey (USC&GS) IDB PID#: CK1342 SETTING CLASSIFICATION: Concrete pier OPUS PID: LATITUDE: 32° 50.9' N ( 32.84830) LONGITUDE: 80° 3.0' W ( -80.05000) The primary bench mark is a disk set in the concrete top at the NW end of the NE pier of the railroad drawbridge over Ashley River, 12.19 m (40.0 ft) NE of bench mark A 17 1933 5.538, 3 m (10 ft) NW of the NW railroad track, and 2.29 m (7.5 ft) below the track.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 5 Station ID: 8665002 PUBLICATION DATE: 05/06/2003 Name: DRAYTON, BEES FERRY, ASHLEY RIVER SC NOAA Chart: 11524 Latitude: 32° 50.9' N ( 32.84830) USGS Quad: JOHNS ISLAND Longitude: 80° 3.1' W ( -80.05170) T I D A L B E N C H M A R K S BENCH MARK STAMPING: A 17 1933 5.538 DESIGNATION: A17 MONUMENTATION: Bench Mark disk VM#: 4129 AGENCY: US Coast and Geodetic Survey (USC&GS) IDB PID#: CK1343 SETTING CLASSIFICATION: Concrete pier OPUS PID: LATITUDE: 32° 50.9' N ( 32.84830) LONGITUDE: 80° 3.0' W ( -80.05000) The bench mark is a disk set in the top center concrete pier on the draw portion of the drawbridge, 6 m (20 ft) NE of the tower control house, 2 m (6 ft) NW of the centerline of the NW track, and 2 m (7 ft) below the track. BENCH MARK STAMPING: NO 3 1933 DESIGNATION: 866 5002 TIDAL 3 MONUMENTATION: Tidal Station disk VM#: 4131 AGENCY: US Coast and Geodetic Survey (USC&GS) IDB PID#: CK1341 SETTING CLASSIFICATION: Concrete monument OPUS PID: LATITUDE: 32° 50.8' N ( 32.84670) LONGITUDE: 80° 3.0' W ( -80.05000) The bench mark is a disk set in a concrete mounment at the SW end of the railroad drawbridge over Ashley River, 19.45 m (63.8 ft) SE of bench mark NO 5 1974, 13.20 m (43.3 ft) SSW of bench mark NO 4 1974, 13 m (43 ft) south of the south end of the drawbridge, 12.34 m (40.5 ft) ENE of a steel post with sign ASHLEY RIVER, and 9.72 m (31.9 ft) ESE of a concrete abutment with a light signal. Note: The bench mark has been hit by machinery.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 5 Station ID: 8665002 PUBLICATION DATE: 05/06/2003 Name: DRAYTON, BEES FERRY, ASHLEY RIVER SC NOAA Chart: 11524 Latitude: 32° 50.9' N ( 32.84830) USGS Quad: JOHNS ISLAND Longitude: 80° 3.1' W ( -80.05170) T I D A L B E N C H M A R K S BENCH MARK STAMPING: NO 4 1974 DESIGNATION: 866 5002 TIDAL 4 MONUMENTATION: Tidal Station disk VM#: 4132 AGENCY: National Geodetic Survey (NGS) IDB PID#: CK1345 SETTING CLASSIFICATION: Concrete abutment OPUS PID#: CK1345 LATITUDE: 32° 50.8' N ( 32.84670) LONGITUDE: 80° 3.0' W ( -80.05000) The bench mark is a disk set in the SE bridge abutment at the south end of the drawbridge, 17.19 m (56.4 ft) NE of bench mark NO 5 1974, 2 m (8 ft) east of the SE rail of the SE track, 0.46 m (1.5 ft) NE of the edge of the concrete abutment, and 2.01 m (6.6 ft) below the track. BENCH MARK STAMPING: NO 5 1974 DESIGNATION: 866 5002 TIDAL 5 MONUMENTATION: Tidal Station disk VM#: 4133 AGENCY: National Geodetic Survey (NGS) IDB PID#: CK1344 SETTING CLASSIFICATION: Concrete foundation OPUS PID: LATITUDE: 32° 50.8' N ( 32.84670) LONGITUDE: 80° 3.0' W ( -80.05000) The bench mark is a disk set in the top of the concrete base of signal light C, 17.31 m (56.8 ft) west of the SE bridge abutment at the south end of the drawbridge, 13.93 m (45.7 ft) SW of the SW bridge abutment, 2.50 m (8.2 ft) NW of the NW rail of the NW track, and 0.76 m (2.5 ft) above the ground.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 5 Station ID: 8665002 PUBLICATION DATE: 05/06/2003 Name: DRAYTON, BEES FERRY, ASHLEY RIVER SC NOAA Chart: 11524 Latitude: 32° 50.9' N ( 32.84830) USGS Quad: JOHNS ISLAND Longitude: 80° 3.1' W ( -80.05170) T I D A L D A T U M S Tidal datums at DRAYTON, BEES FERRY, ASHLEY RIVER based on: LENGTH OF SERIES: 12 MONTHS TIME PERIOD: July 1988 - June 1989 TIDAL EPOCH: 1983-2001 CONTROL TIDE STATION: 8665530 CHARLESTON, COOPER RIVER ENTRANCE Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS: HIGHEST OBSERVED WATER LEVEL (03/09/1989) = 2.289 MEAN HIGHER HIGH WATER MHHW = 1.892 MEAN HIGH WATER MHW = 1.795 North American Vertical Datum NAVD88 = 1.027 MEAN SEA LEVEL MSL = 1.009 MEAN TIDE LEVEL MTL = 0.928 MEAN LOW WATER MLW = 0.060 MEAN LOWER LOW WATER MLLW = 0.000 LOWEST OBSERVED WATER LEVEL (04/07/1989) = -0.607 North American Vertical Datum (NAVD88) Bench Mark Elevation Information In METERS above: Stamping or Designation MLLW MHW NO 1 1933 2.497 0.702 A 17 1933 5.538 2.397 0.602 NO 3 1933 3.564 1.769 NO 4 1974 4.250 2.455 NO 5 1974 5.101 3.306
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 5 Station ID: 8665002 PUBLICATION DATE: 05/06/2003 Name: DRAYTON, BEES FERRY, ASHLEY RIVER SC NOAA Chart: 11524 Latitude: 32° 50.9' N ( 32.84830) USGS Quad: JOHNS ISLAND Longitude: 80° 3.1' W ( -80.05170) 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.