U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 6 PUBLICATION DATE: 09/20/1989 Station ID: 8662799 SUPERCEDED DATE: 04/21/2003 Name: SOUTH SANTEE BRIDGE AT U.S. 17, SOUTH SANTEE RIVER SOUTH CAROLINA NOAA Chart: 11511 Latitude: 33° 11.1' N USGS Quad: SANTEE Longitude: 79° 24.4' W To reach the tidal bench marks from Cooper River Bridge in Charleston, proceed north on U.S. Highway 17 for 44 miles (71 km) to the John T. Stevens Memorial Bridge crossing South Santee River. The bench marks are along the northbound and southbound lanes of U.S. Highway 17. The gage and staff are on a dock under the SW end of the southbound lane of U.S. Highway 17. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: V 124 1962 MONUMENTATION: Survey Disk VM#: 599 AGENCY: PID#: DD0688 SETTING CLASSIFICATION: Concrete Abutment The bench mark is set flush in the concrete bridge abutment at the SW end of the southbound bridge, 96.0 feet (29.3 m) west of Bench Mark 2799 G 1978, 33.6 feet (10.2 m) west of the John T. Stevens Memorial Bridge Monument, 13.8 feet (4.2 m) west of the centerline of U.S. Highway 17 South, 2.3 feet (0.7 m) SE of the SW bridge railing of the southbound lane, and 1.0 foot (0.3 m) above road level. BENCH MARK STAMPING: SS NO 2 1975 MONUMENTATION: Survey Disk VM#: 600 AGENCY: PID#: DD0947 SETTING CLASSIFICATION: Copper-clad Steel Rod The bench mark is 0.15 mile (0.24 km) SW of the south end of the bridge, 86.4 feet (26.3 m) WNW of the centerline of U.S. Highway 17 South, 27.5 feet (8.4 m) NNE of a 2.5-foot (0.8 m) diameter pine tree, 18.6 feet (5.7 m) WNW of the tree line, 13.6 feet (4.1 m) SSW of a 1.5-foot (0.5 m) diameter oak tree, and 2.0 feet (0.6 m) east of a witness post. The bench mark is crimped to a copper-clad steel rod driven 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and Atmospheric Administration National Ocean Service Page 2 of 6 PUBLICATION DATE: 09/20/1989 Station ID: 8662799 SUPERCEDED DATE: 04/21/2003 Name: SOUTH SANTEE BRIDGE AT U.S. 17, SOUTH SANTEE RIVER SOUTH CAROLINA NOAA Chart: 11511 Latitude: 33° 11.1' N USGS Quad: SANTEE Longitude: 79° 24.4' W T I D A L B E N C H M A R K S BENCH MARK STAMPING: SS NO 3 1975 MONUMENTATION: Survey Disk VM#: 601 AGENCY: PID#: DD0949 SETTING CLASSIFICATION: Copper-clad Steel Rod The bench mark is WSW of the south end of the bridge, 37.3 feet (11.4 m) west of a set of twin pine trees, 35.0 feet (10.7 m) north of the centerline of the abandoned road bed of old U.S. Highway 17, and 2.6 feet (0.8 m) east of a witness post with sign. The bench mark is at ground level, crimped to a copper-clad steel rod driven to refusal, and encased in a 4-inch PVC pipe and concrete kickblock. BENCH MARK STAMPING: S.C. GEOD.S. CT 103 RESET 1976 MONUMENTATION: Survey Disk VM#: 602 AGENCY: PID#: DD0950 SETTING CLASSIFICATION: Concrete Monument The bench mark is set flush in a concrete monument on an embankment on the south side of U.S. Highway 17 North, 113.0 feet (34.4 m) NNE of a concrete marker delineating the highway right-of-way, 58.0 feet (17.7 m) ESE of the centerline of U.S. Highway 17 North, 1.6 feet (0.5 m) SSW of a witness post with sign, and 0.3 foot (0.1 m) above ground level.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 6 PUBLICATION DATE: 09/20/1989 Station ID: 8662799 SUPERCEDED DATE: 04/21/2003 Name: SOUTH SANTEE BRIDGE AT U.S. 17, SOUTH SANTEE RIVER SOUTH CAROLINA NOAA Chart: 11511 Latitude: 33° 11.1' N USGS Quad: SANTEE Longitude: 79° 24.4' W T I D A L B E N C H M A R K S BENCH MARK STAMPING: 2799 G 1978 MONUMENTATION: Survey Disk VM#: 603 AGENCY: PID#: DD0946 SETTING CLASSIFICATION: Concrete Bridge Abutment The bench mark is set flush in the SE bridge abutment of the northbound bridge of U.S. Highway 17, 96.0 feet (29.3 m) east of Bench Mark V 124 1962, 64.5 feet (19.7 m) east of the John T. Stevens Memorial Bridge Monument, 24.5 feet (7.5 m) east of the centerline of U.S. Highway 17 North, 7.0 feet (2.1 m) NNW of a sign marking the Georgetown County line and South Santee River, and 0.8 foot (0.2 m) east of the SE bridge railing of the northbound bridge. BENCH MARK STAMPING: HORZ 022 033 1981 MONUMENTATION: Survey Disk VM#: 604 AGENCY: PID#: DD2400 SETTING CLASSIFICATION: Concrete Monument The bench mark is set flush in a concrete monument in the grass median strip between the northbound/southbound lanes of U.S. Highway 17, at the east end of the bridge, 30.9 feet (9.4 m) ESE of the centerline of U.S. Highway 17 South, 25.9 feet (7.9 m) NNW of Bench Mark RM 1 022 033 1981, 5.7 feet (1.7 m) east of a metal guard rail along the southbound lane of the highway, 4.7 feet (1.4 m) west of the guard rail along the northbound lane of the highway, and 1.7 feet (0.5 m) NNE of a witness post with sign.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 6 PUBLICATION DATE: 09/20/1989 Station ID: 8662799 SUPERCEDED DATE: 04/21/2003 Name: SOUTH SANTEE BRIDGE AT U.S. 17, SOUTH SANTEE RIVER SOUTH CAROLINA NOAA Chart: 11511 Latitude: 33° 11.1' N USGS Quad: SANTEE Longitude: 79° 24.4' W T I D A L B E N C H M A R K S BENCH MARK STAMPING: RM1 022 033 1981 MONUMENTATION: Survey Disk VM#: 605 AGENCY: PID#: DD2401 SETTING CLASSIFICATION: Concrete Monument The bench mark is set flush in a concrete monument in the grass median strip between the northbound/southbound lanes of U.S. Highway 17, at the east end of the bridge, 31.1 feet (9.5 m) ESE of the centerline of U.S. Highway 17 South, 9.1 feet (2.8 m) east of the metal guard rail along the southbond lane of the highway, 7.5 feet (2.3 m) west of the guard rail along the northbound lane of the highway, and 1.3 feet (0.4 m) east of a witness post with sign.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 6 PUBLICATION DATE: 09/20/1989 Station ID: 8662799 SUPERCEDED DATE: 04/21/2003 Name: SOUTH SANTEE BRIDGE AT U.S. 17, SOUTH SANTEE RIVER SOUTH CAROLINA NOAA Chart: 11511 Latitude: 33° 11.1' N USGS Quad: SANTEE Longitude: 79° 24.4' W T I D A L D A T U M S Tidal datums at SOUTH SANTEE BRIDGE AT U.S. 17, SOUTH SANTEE RIVER based on: LENGTH OF SERIES: 12 YEARS TIME PERIOD: 1977-1988 TIDAL EPOCH: 1960-1978 CONTROL TIDE STATION: 8665530 CHARLESTON Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET: HIGHEST OBSERVED WATER LEVEL (03/12/1987) = 7.18 MEAN HIGHER HIGH WATER MHHW = 4.54 MEAN HIGH WATER MHW = 4.27 MEAN TIDE LEVEL MTL = 2.22 MEAN LOW WATER MLW = 0.17 MEAN LOWER LOW WATER MLLW = 0.00 LOWEST OBSERVED WATER LEVEL (04/06/1982) = -1.44 North American Vertical Datum (NAVD88) Bench Mark Elevation Information In FEET above: Stamping or Designation MLLW MHW V 124 1962 24.00 19.73 SS NO 2 1975 23.85 19.58 SS NO 3 1975 20.71 16.44 S.C. GEOD.S. CT 103 RESET 1976 24.41 20.14 2799 G 1978 24.02 19.75 HORZ 022 033 1981 16.37 12.10 RM1 022 033 1981 16.89 12.62
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 6 of 6 PUBLICATION DATE: 09/20/1989 Station ID: 8662799 SUPERCEDED DATE: 04/21/2003 Name: SOUTH SANTEE BRIDGE AT U.S. 17, SOUTH SANTEE RIVER SOUTH CAROLINA NOAA Chart: 11511 Latitude: 33° 11.1' N USGS Quad: SANTEE Longitude: 79° 24.4' W 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 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.