U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 5 Station ID: 8660642 PUBLICATION DATE: 06/28/2004 Name: NORTH MYRTLE BEACH SC NOAA Chart: 11535 Latitude: 33° 46.0' N ( 33.76670) USGS Quad: NIXONVILLE Longitude: 78° 48.9' W ( -78.81500) To reach the tidal bench marks from the intersection of U.S. Highway 17 Business (Kings Highway) and U.S. Highway 501 (Main Street) in Myrtle Beach, proceed NW on U.S. Highway 501 for 3.5 km (2.2 mi) to U.S. Highway 17 Bypass, then NE on U.S. Highway 17 Bypass for 11.4 km (7.1 mi) to State Road 317, then NW on State Road 317 for 0.24 km (0.15 mi) to the Myrtle Beach Tennis Club entrance. The bench marks are along a path to the Intracoastal Waterway and near the tennis club parking lot. The tide gage and staff were on a U.S. Army Corps of Engineers constructed pier at the end of the path behind the tennis club pro shop. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: 0642 A 1977 DESIGNATION: 866 0642 A TIDAL MONUMENTATION: Tidal Station disk VM#: 3720 AGENCY: National Ocean Survey (NOS) IDB PID#: DD1594 SETTING CLASSIFICATION: Copper clad steel rod OPUS PID: LATITUDE: 33° 45.9' N ( 33.76500) LONGITUDE: 78° 48.9' W ( -78.81500) The primary bench mark is a disk crimped to a copper-clad steel rod, located set near two blazed oak trees at the edge of the Intracoastal Waterway, 80.80 m (265.1 ft) SW of Bench Mark 0642 C 1977, 6.00 m (19.7 ft) SSE of the edge of the waterway, 1.16 m (3.8 ft) east of the blazed 0.8-foot (0.2 m) diameter oak tree, and 9.14 m (3.0 ft) SW of the blazed 0.40 m (1.3 ft) diameter oak tree. The bench mark is level with the ground, crimped to a copper-clad steel rod driven 6 m (20 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 5 Station ID: 8660642 PUBLICATION DATE: 06/28/2004 Name: NORTH MYRTLE BEACH SC NOAA Chart: 11535 Latitude: 33° 46.0' N ( 33.76670) USGS Quad: NIXONVILLE Longitude: 78° 48.9' W ( -78.81500) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 0642 C 1977 DESIGNATION: 866 0642 C TIDAL MONUMENTATION: Tidal Station disk VM#: 3721 AGENCY: National Ocean Survey (NOS) IDB PID#: DD1593 SETTING CLASSIFICATION: Copper clad steel rod OPUS PID: LATITUDE: 33° 46.0' N ( 33.76670) LONGITUDE: 78° 48.9' W ( -78.81500) The bench mark is a disk crimped to a copper-clad steel rod, set near a double-trunk oak tree at the edge of the Intracoastal Waterway, 44.68 m (146.6 ft) SW of Bench Mark 0642 D 1977, 7.25 m (23.8 ft) NE of a blazed 0.52 m (1.7 ft) diameter oak tree, 6.71 m (22.2 ft) SW of the double-trunk oak tree, and 4 m (13 ft) SE of the edge of the waterway. The bench mark is level with the ground, crimped to a copper-clad steel rod driven 4 m (13 ft) to refusal, and encased in a 4-inch PVC pipe and concrete kickblock. BENCH MARK STAMPING: 0642 D 1977 DESIGNATION: 866 0642 D TIDAL MONUMENTATION: Tidal Station disk VM#: 3722 AGENCY: National Ocean Survey (NOS) IDB PID#: DD1592 SETTING CLASSIFICATION: Copper clad steel rod OPUS PID: LATITUDE: 33° 46.0' N ( 33.76670) LONGITUDE: 78° 48.9' W ( -78.81500) The bench mark is a disk crimped to a copper-clad steel rod, set near a blazed oak tree at the edge of the Intracoastal Waterway, 35.91 m (117.8 ft) NW of the NW corner of the clubhouse, 16.40 m (53.8 ft) WNW of a 0.3 m (1 ft) diameter lone cedar tree, 12.22 m (40.1 ft) NNE of a 1.7-foot (0.5 m) diameter pine tree, and 6 m (20 ft) ENE of the blazed 0.24 m (0.8 ft) diameter oak tree. The bench mark is level with the ground, crimped to a copper-clad steel rod driven 4 m (13 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 5 Station ID: 8660642 PUBLICATION DATE: 06/28/2004 Name: NORTH MYRTLE BEACH SC NOAA Chart: 11535 Latitude: 33° 46.0' N ( 33.76670) USGS Quad: NIXONVILLE Longitude: 78° 48.9' W ( -78.81500) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 0642 E 1982 DESIGNATION: 866 0642 E TIDAL MONUMENTATION: Tidal Station disk VM#: 3723 AGENCY: National Ocean Survey (NOS) IDB PID#: DD1591 SETTING CLASSIFICATION: Stainless steel rod OPUS PID: LATITUDE: 33° 45.9' N ( 33.76500) LONGITUDE: 78° 48.7' W ( -78.81170) The bench mark is a disk crimped to a stainless steel rod, set in a wooded area where the pavement ends, 98 m (320 ft) SE of the pro-shop flag pole, 30.91 m (101.4 ft) south of the south corner of a 2 m (7 ft) high chain link fence surrounding a tennis court, 13 m (43 ft) NNE of the centerline of the paved road, 12.98 m (42.6 ft) east of a 0.52 m (1.7 ft) diameter pine tree, and 9.30 m (30.5 ft) west of a blazed 0.40 m (1.3 ft) diameter pine tree. The bench mark is level with the ground, crimped to a stainless steel rod driven 10 m (34 ft) to refusal, and encased in a PVC pipe and concrete kickblock. BENCH MARK STAMPING: 0642 F 1982 DESIGNATION: 866 0642 F TIDAL MONUMENTATION: Tidal Station disk VM#: 3724 AGENCY: National Ocean Survey (NOS) IDB PID#: DD1590 SETTING CLASSIFICATION: Stainless steel rod OPUS PID: LATITUDE: 33° 45.8' N ( 33.76330) LONGITUDE: 78° 48.7' W ( -78.81170) The bench mark is a disk crimped to a stainless steel rod, set near a row of three pine trees in the north angle of the paved road leading to Myrtle Beach Tennis Club, 44.81 m (147.0 ft) SW of utility pole #18, 29.99 m (98.4 ft) NW of the centerline of the southbound lanes of the highway, 8.75 m (28.7 ft) NE of the centerline of the paved road, and 2.01 m (6.6 ft) west of the middle tree. The bench mark is level with the ground, crimped to a stainless steel rod driven 14 m (46 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 4 of 5 Station ID: 8660642 PUBLICATION DATE: 06/28/2004 Name: NORTH MYRTLE BEACH SC NOAA Chart: 11535 Latitude: 33° 46.0' N ( 33.76670) USGS Quad: NIXONVILLE Longitude: 78° 48.9' W ( -78.81500) T I D A L D A T U M S Tidal datums at NORTH MYRTLE BEACH based on: LENGTH OF SERIES: 4 MONTHS TIME PERIOD: April 1977 - July 1977 TIDAL EPOCH: 1983-2001 CONTROL TIDE STATION: 8660854 COMBINATION BRIDGE Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS: MEAN HIGHER HIGH WATER MHHW = 0.657 MEAN HIGH WATER MHW = 0.591 MEAN TIDE LEVEL MTL = 0.320 MEAN SEA LEVEL MSL = 0.302 North American Vertical Datum NAVD88 = 0.104 MEAN LOW WATER MLW = 0.049 MEAN LOWER LOW WATER MLLW = 0.000 North American Vertical Datum (NAVD88) Bench Mark Elevation Information In METERS above: Stamping or Designation MLLW MHW 0642 A 1977 8.244 7.653 0642 C 1977 8.099 7.508 0642 D 1977 7.793 7.202 0642 E 1982 8.644 8.053 0642 F 1982 11.440 10.849
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 5 Station ID: 8660642 PUBLICATION DATE: 06/28/2004 Name: NORTH MYRTLE BEACH SC NOAA Chart: 11535 Latitude: 33° 46.0' N ( 33.76670) USGS Quad: NIXONVILLE Longitude: 78° 48.9' W ( -78.81500) 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.