U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 6 Station ID: 8662549 PUBLICATION DATE: 02/05/2004 Name: SOUTH ISLAND FERRY, WINYAH BAY SC NOAA Chart: 11532 Latitude: 33° 15.1' N ( 33.25170) USGS Quad: GEORGETOWN SOUTH Longitude: 79° 16.1' W ( -79.26830) To reach the tidal bench marks from the north end of the North Santee Bridge at U.S. Highway 17, proceed north on Highway 17 for 1.0 km (0.6 mi) to State Road S-22-30 (North Santee River Road), then right and proceed east on State Road S-22-30 for 7.7 km (4.8 mi) to a dirt road leading to Annadale Plantation, then bear left and continue on the paved road (still State Road S-22-30) for 4.5 km (2.8 mi) to State Road S-22-18, then turn right onto State Road S-22-18 for 1.1 km (0.7 mi) to the ferry across the Intracoastal Waterway. The bench marks are near the ferry landing. The tide gage and staff were on a dock just north of the ferry landing. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: 2549 A 1976 DESIGNATION: 866 2549 A TIDAL MONUMENTATION: Tidal Station disk VM#: 3934 AGENCY: National Ocean Survey (NOS) IDB PID#: DD0868 SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID: LATITUDE: 33° 15.1' N ( 33.25170) LONGITUDE: 79° 16.1' W ( -79.26830) The primary bench mark is a disk located next to the green wooden ferry attendants watch shed near a utility pole and chimney, 9.60 m (31.5 ft) south of a 0.3 m (1 ft) diameter pine tree near the edge of the marsh, 7.74 m (25.4 ft) east of the center of a dock, 1.10 m (3.6 ft) SE of the utility pole with witness sign, and 0.79 m (2.6 ft) ENE of the southeastern-most corner of the ferry attendants watch shed. The bench mark is set at ground level, crimped to the top of a copper-clad steel rod driven 9.8 m (32 ft) to refusal, and encased in a 4-inch PVC pipe and concrete kickblock.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 6 Station ID: 8662549 PUBLICATION DATE: 02/05/2004 Name: SOUTH ISLAND FERRY, WINYAH BAY SC NOAA Chart: 11532 Latitude: 33° 15.1' N ( 33.25170) USGS Quad: GEORGETOWN SOUTH Longitude: 79° 16.1' W ( -79.26830) T I D A L B E N C H M A R K S BENCH MARK STAMPING: BM 1 1935 DESIGNATION: 866 2549 TIDAL 1 MONUMENTATION: Tidal Station disk VM#: 3933 AGENCY: US Coast & Geodetic Survey (USC&GS) IDB PID#: DD0871 SETTING CLASSIFICATION: Concrete monument OPUS PID: LATITUDE: 33° 15.0' N ( 33.25000) LONGITUDE: 79° 16.0' W ( -79.26670) The bench mark is a disk set in a concrete monument, 32.10 m (105.3 ft) ESE of bench mark 2549 C 1976, 10.27 m (33.7 ft) west of utility pole #U.S. Coast Guard 32, 9.20 m (30.2 ft) NNE of utility pole #40-5-A, 7 m (23 ft) SW of the centerline of the dirt road leading to the ferry landing, and 0.21 m (0.7 ft) above ground level. BENCH MARK STAMPING: 2549 B 1976 DESIGNATION: 866 2549 B TIDAL MONUMENTATION: Tidal Station disk VM#: 3935 AGENCY: National Ocean Survey (NOS) IDB PID#: DD0869 SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID: LATITUDE: 33° 15.1' N ( 33.25170) LONGITUDE: 79° 16.0' W ( -79.26670) The bench mark is a disk located north of the dirt road leading to the ferry, 61 m (201 ft) east of bench mark 2549 A 1976, 22.19 m (72.8 ft) NNE of the centerline of the dirt road, 3.87 m (12.7 ft) ENE of a 0.61 m (2.0 ft) diameter pine tree, and 1.43 m (4.7 ft) NW of a utility pole with 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) to refusal, and encased in a 4-inch PVC pipe and concrete kickblock.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 6 Station ID: 8662549 PUBLICATION DATE: 02/05/2004 Name: SOUTH ISLAND FERRY, WINYAH BAY SC NOAA Chart: 11532 Latitude: 33° 15.1' N ( 33.25170) USGS Quad: GEORGETOWN SOUTH Longitude: 79° 16.1' W ( -79.26830) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 2549 C 1976 DESIGNATION: 866 2549 C TIDAL MONUMENTATION: Tidal Station disk VM#: 3936 AGENCY: National Ocean Survey (NOS) IDB PID#: DD0870 SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID: LATITUDE: 33° 15.0' N ( 33.25000) LONGITUDE: 79° 16.0' W ( -79.26670) The bench mark is a disk located near the green cinder block ferry attendants house, 37 m (120 ft) south of bench mark 2549 B 1976, 10.91 m (35.8 ft) SE of the NE corner of the ferry attendants house, 9.63 m (31.6 ft) SW of the centerline of the dirt road, 3.75 m (12.3 ft) NW of the centerline of a drainage ditch running perpendicular to the dirt road, and 1.52 m (5.0 ft) north of a utility pole with witness sign and meter. The bench mark is set at ground level, crimped to the top of a copper-clad steel rod driven 9.8 m (32 ft) to refusal, and encased in a 4-inch PVC pipe and concrete kickblock.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 6 Station ID: 8662549 PUBLICATION DATE: 02/05/2004 Name: SOUTH ISLAND FERRY, WINYAH BAY SC NOAA Chart: 11532 Latitude: 33° 15.1' N ( 33.25170) USGS Quad: GEORGETOWN SOUTH Longitude: 79° 16.1' W ( -79.26830) T I D A L B E N C H M A R K S BENCH MARK STAMPING: S 147 1979 DESIGNATION: S 147 MONUMENTATION: Bench Mark disk VM#: 3937 AGENCY: US Coast & Geodetic Survey (USC&GS) IDB PID#: DD0874 SETTING CLASSIFICATION: Stainless steel rod OPUS PID: LATITUDE: 33° 14.9' N ( 33.24830) LONGITUDE: 79° 15.5' W ( -79.25830) The bench mark is a disk set along the main dirt road, 7.32 m (24.0 ft) SE of the bend in a 0.46 m (1.5 ft) wide drainage ditch, 7.07 m (23.2 ft) south of the centerline of the dirt road leading the the ferry, 5.79 m (19.0 ft) west of a secondary dirt road, and 0.61 m (2.0 ft) west of a witness post with sign. The bench mark is at ground level, crimped to the top of a stainless steel rod driven 2.7 m (8.9 ft) to refusal.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 6 Station ID: 8662549 PUBLICATION DATE: 02/05/2004 Name: SOUTH ISLAND FERRY, WINYAH BAY SC NOAA Chart: 11532 Latitude: 33° 15.1' N ( 33.25170) USGS Quad: GEORGETOWN SOUTH Longitude: 79° 16.1' W ( -79.26830) T I D A L D A T U M S Tidal datums at SOUTH ISLAND FERRY, WINYAH BAY based on: LENGTH OF SERIES: 1 YEAR TIME PERIOD: January 1977 - December 1977 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 (05/31/1977) = 1.628 MEAN HIGHER HIGH WATER MHHW = 1.256 MEAN HIGH WATER MHW = 1.168 North American Vertical Datum NAVD88 = 0.662 MEAN SEA LEVEL MSL = 0.613 MEAN TIDE LEVEL MTL = 0.606 MEAN LOW WATER MLW = 0.044 MEAN LOWER LOW WATER MLLW = 0.000 LOWEST OBSERVED WATER LEVEL (02/05/1977) = -0.490 North American Vertical Datum (NAVD88) Bench Mark Elevation Information In METERS above: Stamping or Designation MLLW MHW 2549 A 1976 1.695 0.527 BM 1 1935 1.959 0.791 2549 B 1976 1.573 0.405 2549 C 1976 1.815 0.647 S 147 1979 2.541 1.373
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 6 of 6 Station ID: 8662549 PUBLICATION DATE: 02/05/2004 Name: SOUTH ISLAND FERRY, WINYAH BAY SC NOAA Chart: 11532 Latitude: 33° 15.1' N ( 33.25170) USGS Quad: GEORGETOWN SOUTH Longitude: 79° 16.1' W ( -79.26830) 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.