U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 5 Station ID: 8665101 PUBLICATION DATE: 03/09/2004 Name: COSGROVE BRIDGE, ASHLEY RIVER SC NOAA Chart: 11524 Latitude: 32° 50.1' N ( 32.83500) USGS Quad: CHARLESTON Longitude: 79° 59.2' W ( -79.98670) To reach the tidal bench marks from the intersection of U.S. Highway 26 and State Highway 7, proceed SW on State Highway 7 (Sam Rittenberg Boulevard) for 1.3 km (0.8 mi) to the SW end of Cosgrove Bridge, just over the Ashley River. The bench marks are located near the bridge. The tide gage and staff were located at the end of the dock extending beneath the southern portion of the bridge. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: 5101 E 1976 DESIGNATION: 866 5101 E TIDAL MONUMENTATION: Tidal Station disk VM#: 4137 AGENCY: National Ocean Survey (NOS) IDB PID#: CJ0481 SETTING CLASSIFICATION: Copper clad steel rod OPUS PID: LATITUDE: 32° 50.1' N ( 32.83500) LONGITUDE: 79° 59.2' W ( -79.98670) The primary bench mark is a disk located on the west shoulder of State Highway 7 just past the SW end of the bridge, 101 m (333 ft) SSW of bench mark 5101 D 1976, 94.40 m (309.7 ft) south of the SW corner of the bridge, 7.19 m (23.6 ft) west of the west edge of the highway pavement, and 1.65 m (5.4 ft) north of SCE&G utility pole #160729. The bench mark is set 6 cm (0.2 ft) below ground level, crimped to the top of a copper-clad steel rod driven to refusal, and encased in a PVC pipe and concrete kickblock. NOTE: Mark not found in 1992 by NGS.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 5 Station ID: 8665101 PUBLICATION DATE: 03/09/2004 Name: COSGROVE BRIDGE, ASHLEY RIVER SC NOAA Chart: 11524 Latitude: 32° 50.1' N ( 32.83500) USGS Quad: CHARLESTON Longitude: 79° 59.2' W ( -79.98670) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 5101 B 1976 DESIGNATION: 866 5101 B TIDAL MONUMENTATION: Tidal Station disk VM#: 4134 AGENCY: National Ocean Survey (NOS) IDB PID#: CJ0478 SETTING CLASSIFICATION: Bridge abutment OPUS PID#: CJ0478 LATITUDE: 32° 50.1' N ( 32.83500) LONGITUDE: 79° 59.2' W ( -79.98670) The bench mark is a disk set flush in the SE bridge abutment, 2.62 m (8.6 ft) north of the north side of the Memorial Bridge monument, and 1.13 m (3.7 ft) SE of the east edge of State Highway 7 pavement. BENCH MARK STAMPING: 5101 C 1976 DESIGNATION: 866 5101 C TIDAL MONUMENTATION: Tidal Station disk VM#: 4135 AGENCY: National Ocean Survey (NOS) IDB PID#: CJ0479 SETTING CLASSIFICATION: Copper clad steel rod OPUS PID: LATITUDE: 32° 50.1' N ( 32.83500) LONGITUDE: 79° 59.2' W ( -79.98670) The bench mark is a disk located 53 m (174 ft) south of the SE bridge abutment, 7.80 m (25.6 ft) SE of the east edge of the highway pavement, 2.38 m (7.8 ft) north of utility pole #160727, and 2.13 m (7.0 ft) north of a witness post. The bench mark is set 6 cm (0.2 ft) below ground level, crimped to the top of 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 3 of 5 Station ID: 8665101 PUBLICATION DATE: 03/09/2004 Name: COSGROVE BRIDGE, ASHLEY RIVER SC NOAA Chart: 11524 Latitude: 32° 50.1' N ( 32.83500) USGS Quad: CHARLESTON Longitude: 79° 59.2' W ( -79.98670) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 5101 D 1976 DESIGNATION: 866 5101 D TIDAL MONUMENTATION: Tidal Station disk VM#: 4136 AGENCY: National Ocean Survey (NOS) IDB PID#: CJ0480 SETTING CLASSIFICATION: Bridge abutment OPUS PID: LATITUDE: 32° 50.1' N ( 32.83500) LONGITUDE: 79° 59.2' W ( -79.98670) The bench mark is a disk set flush in the NW corner of the southernmost bridge support, 0.98 m (3.2 ft) north of the north side of the south bridge abutment wall, 0.18 m (0.6 ft) south of the north side of the base support, and 0.18 m (0.6 ft) east of the west side of the base support. BENCH MARK STAMPING: 5101 G 1983 DESIGNATION: 866 5101 G TIDAL MONUMENTATION: Tidal Station disk VM#: 17290 AGENCY: National Ocean Survey (NOS) IDB PID#: CJ0482 SETTING CLASSIFICATION: Stainless steel rod OPUS PID: LATITUDE: 32° 49.8' N ( 32.83000) LONGITUDE: 79° 59.4' W ( -79.99000) The bench mark is a disk located 4.26 km (2.65 mi) north along state highway 7 from the junction of state highway 61 in St. Andrews, 13.69 m (44.9 ft) northwest of the centerline of the southbound lanes of the highway, 1.89 m (6.2 ft) northwest of utility pole number 92636, 0.6 m (2.0 ft) above highway level, and 0.3 m (1.0 ft) southeast of a witness post. The bench mark is recessed 9 cm (0.3 ft) below the ground surface, crimped to the top of a stainless steel rod driven 11.0 m (36 ft) to refusal, and encased in a 5-inch PVC pipe and concrete kickblock.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 5 Station ID: 8665101 PUBLICATION DATE: 03/09/2004 Name: COSGROVE BRIDGE, ASHLEY RIVER SC NOAA Chart: 11524 Latitude: 32° 50.1' N ( 32.83500) USGS Quad: CHARLESTON Longitude: 79° 59.2' W ( -79.98670) T I D A L D A T U M S Tidal datums at COSGROVE BRIDGE, ASHLEY RIVER based on: LENGTH OF SERIES: 7 MONTHS TIME PERIOD: April 1976 - October 1976 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: MEAN HIGHER HIGH WATER MHHW = 1.864 MEAN HIGH WATER MHW = 1.759 North American Vertical Datum NAVD88 = 1.043 MEAN SEA LEVEL MSL = 0.973 MEAN TIDE LEVEL MTL = 0.910 MEAN LOW WATER MLW = 0.060 MEAN LOWER LOW WATER MLLW = 0.000 North American Vertical Datum (NAVD88) Bench Mark Elevation Information In METERS above: Stamping or Designation MLLW MHW 5101 E 1976 4.546 2.787 5101 B 1976 7.718 5.959 5101 C 1976 5.015 3.256 5101 D 1976 5.079 3.320 5101 G 1983 5.206 3.447
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 5 Station ID: 8665101 PUBLICATION DATE: 03/09/2004 Name: COSGROVE BRIDGE, ASHLEY RIVER SC NOAA Chart: 11524 Latitude: 32° 50.1' N ( 32.83500) USGS Quad: CHARLESTON Longitude: 79° 59.2' W ( -79.98670) 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.