U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 4 Station ID: 8666699 PUBLICATION DATE: 08/11/2003 Name: BEARS BLUFF, WADMALAW RIVER SC NOAA Chart: 11522 Latitude: 32° 38.8' N ( 32.64670) USGS Quad: ADAMS RUN Longitude: 80° 15.4' W ( -80.25670) To reach the tidal bench marks from the Johns Island post office proceed SW along State Highway 700 (Maybank Highway) for 9.3 km (5.8 mi) to County Road S-10-316 (Bear Bluff Road), then turn right and continue NW along County Road S-10-316 for 14.2 km (8.8 mi) to the end of the pavement to the entrance of the U.S. Fish & Wildlife Orangeburg National Fish Hatchery, Bears Bluff Station, then continue SW for 0.3 km (0.2 mi) along a sand road that runs parallel with a chain link fence, and then proceed 0.2 km (0.1 mi) north through a chain link gate to the office. The bench marks are along a sand road that follows the river. The tide gauge and staff were at the end of the pier on the Wadmalaw River. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: 6699 A 1977 DESIGNATION: 866 6699 A TIDAL MONUMENTATION: Tidal Station disk VM#: 4339 AGENCY: National Ocean Survey (NOS) IDB PID#: CK2579 SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID: LATITUDE: 32° 38.8' N ( 32.64670) LONGITUDE: 80° 15.3' W ( -80.25500) The primary bench mark is a disk located at the shore end of the pier, 5 m (18 ft) NNW of the edge of a small fish pond, 3 m (10 ft) NNE of the centerline of the sand road, and 1.10 m (3.6 ft) SSW of a 2 m (6 ft) high seawall. The bench mark is set at ground level, crimped to the top of a copper-clad steel rod driven 12.2 m (40 ft) to refusal, and encased in a PVC pipe and 0.43 m (1.4 ft) diameter concrete kickblock.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 4 Station ID: 8666699 PUBLICATION DATE: 08/11/2003 Name: BEARS BLUFF, WADMALAW RIVER SC NOAA Chart: 11522 Latitude: 32° 38.8' N ( 32.64670) USGS Quad: ADAMS RUN Longitude: 80° 15.4' W ( -80.25670) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 6699 B 1977 DESIGNATION: 866 6699 B TIDAL MONUMENTATION: Tidal Station disk VM#: 4340 AGENCY: National Ocean Survey (NOS) IDB PID#: CK2578 SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID: LATITUDE: 32° 38.8' N ( 32.64670) LONGITUDE: 80° 15.3' W ( -80.25500) The bench mark is a disk located along the sand road running along the river from the pier to the southern boundary of the station, 7 m (23 ft) east of the approximate edge of a 15 m (50 ft) high river bank, 6.25 m (20.5 ft) west of the centerline of the road, 2.87 m (9.4 ft) NW of the 1 m (4 ft) diameter blazed cedar tree, and 0.76 m (2.5 ft) east of a witness post with sign. The bench mark is set 0.61 m (2.0 feet) above road level, crimped to the top of a copper-clad steel rod driven 8.5 m (28 ft) to refusal, and encased in a PVC pipe and 0.43 m (1.4 ft) diameter concrete kickblock. BENCH MARK STAMPING: 6699 C 1977 DESIGNATION: 866 6699 C TIDAL MONUMENTATION: Tidal Station disk VM#: 4341 AGENCY: National Ocean Survey (NOS) IDB PID#: CK2577 SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID: LATITUDE: 32° 38.8' N ( 32.64670) LONGITUDE: 80° 15.3' W ( -80.25500) The bench mark is a disk located along the sand road running along the river from the pier to the southern boundary of the station, at the fork of two cleared paths, 5.12 m (16.8 ft) SSE of a 2.29 m (7.5 ft) diameter blazed oak tree, 5 m (15 ft) west of the centerline of the sand road, 4.45 m (14.6 ft) north of a lone 2.29 m (7.5 ft) diameter cedar tree, and 0.82 m (2.7 ft) NE of a metal witness post with sign. The bench mark is level with the sand road, crimped to a copper-clad steel rod driven 9.1 m (30 ft) to refusal, and encased in a PVC pipe and concrete kickblock.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 4 Station ID: 8666699 PUBLICATION DATE: 08/11/2003 Name: BEARS BLUFF, WADMALAW RIVER SC NOAA Chart: 11522 Latitude: 32° 38.8' N ( 32.64670) USGS Quad: ADAMS RUN Longitude: 80° 15.4' W ( -80.25670) T I D A L D A T U M S Tidal datums at BEARS BLUFF, WADMALAW RIVER based on: LENGTH OF SERIES: 12 MONTHS TIME PERIOD: October 1977 - September 1978 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 (06/01/1977) = 2.569 MEAN HIGHER HIGH WATER MHHW = 2.041 MEAN HIGH WATER MHW = 1.933 North American Vertical Datum NAVD88 = 1.163 MEAN SEA LEVEL MSL = 1.117 MEAN TIDE LEVEL MTL = 0.999 MEAN LOW WATER MLW = 0.065 MEAN LOWER LOW WATER MLLW = 0.000 LOWEST OBSERVED WATER LEVEL (01/09/1978) = -0.967 North American Vertical Datum (NAVD88) Bench Mark Elevation Information In METERS above: Stamping or Designation MLLW MHW 6699 A 1977 3.301 1.368 6699 B 1977 5.303 3.370 6699 C 1977 6.330 4.397
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 4 Station ID: 8666699 PUBLICATION DATE: 08/11/2003 Name: BEARS BLUFF, WADMALAW RIVER SC NOAA Chart: 11522 Latitude: 32° 38.8' N ( 32.64670) USGS Quad: ADAMS RUN Longitude: 80° 15.4' W ( -80.25670) 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.