U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 4 Station ID: 8665167 PUBLICATION DATE: 10/30/2003 Name: HAMLIN SOUND SC NOAA Chart: 11521 Latitude: 32° 49.6' N ( 32.82670) USGS Quad: FORT MOULTRIE Longitude: 79° 47.2' W ( -79.78670) To reach the tidal bench marks from the east end of the U.S. Highway 17 bridge over Cooper River in Mt. Pleasant, proceed north on U.S. Highway 17 for 12.1 km (7.5 mi) to Hamlin Drive (S-10-504), then turn right and proceed SE on Hamlin Drive for 1.8 km (1.1 mi) to the entrance to Old Hamlin Farms, then turn right onto the dirt driveway and proceed 0.3 km (0.2 mi) to the O.D. Hamlin residence. The bench marks are along the dirt driveway leading to the residence. The tide gage and staff were on the Hamlin private pier. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: 5167 A 1978 DESIGNATION: 866 5167 A TIDAL MONUMENTATION: Tidal Station disk VM#: 4142 AGENCY: National Ocean Survey (NOS) IDB PID#: CJ0283 SETTING CLASSIFICATION: Galvanized steel rod OPUS PID#: CJ0283 LATITUDE: 32° 49.6' N ( 32.82670) LONGITUDE: 79° 47.2' W ( -79.78670) The primary bench mark is a disk located 13.26 m (43.5 ft) NW of a palmetto piling at the land end of another small dock located at the NE side of the island at the end of the causeway leading to the pier, 9.27 m (30.4 ft) north of the land end of a small dock on the west side of the small island, 5.79 m (19.0 ft) WSW of the centerline of the road on the causeway, and 0.27 m (0.9 ft) NE of a metal witness post with sign. The bench mark is set 6 cm (0.2 ft) below ground level, crimped to the top of a galvanized steel rod driven 11.3 m (37 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 2 of 4 Station ID: 8665167 PUBLICATION DATE: 10/30/2003 Name: HAMLIN SOUND SC NOAA Chart: 11521 Latitude: 32° 49.6' N ( 32.82670) USGS Quad: FORT MOULTRIE Longitude: 79° 47.2' W ( -79.78670) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 5167 G 1982 DESIGNATION: 866 5167 G TIDAL MONUMENTATION: Tidal Station disk VM#: 4145 AGENCY: National Ocean Survey (NOS) IDB PID#: CJ1473 SETTING CLASSIFICATION: Stainless steel rod OPUS PID: LATITUDE: 32° 49.8' N ( 32.83000) LONGITUDE: 79° 47.5' W ( -79.79170) The bench mark is a disk located 30.18 m (99.0 ft) south of the SE corner of a 0.61 m (2.0 ft) well, 20.88 m (68.5 ft) SE of the SE corner of the brick steps (the ruins), 11.37 m (37.3 ft) NW of a live oak tree beside the road, 7.32 m (24.0 ft) SW of the centerline of the dirt road leading to the house trailer and pier, and 0.46 m (1.5 ft) SSW of a metal witness post with sign. The bench mark is set 6 cm (0.2 ft) below ground level, crimped to the top of a stainless steel rod driven 13.4 m (44 ft) to refusal, and encased in a 5-inch PVC pipe and concrete kickblock. BENCH MARK STAMPING: 5167 H 1982 DESIGNATION: 866 5167 H TIDAL MONUMENTATION: Tidal Station disk VM#: 4146 AGENCY: National Ocean Survey (NOS) IDB PID#: CJ1474 SETTING CLASSIFICATION: Stainless steel rod OPUS PID: LATITUDE: 32° 49.8' N ( 32.83000) LONGITUDE: 79° 47.4' W ( -79.79000) The bench mark is a disk located 32.31 m (106.0 ft) NE of the centerline of the dirt road, 8.53 m (28.0 ft) ENE of a 0.70 m (2.3 ft) diameter pine tree, 2.13 m (7.0 ft) SW of the ball housing of the trailer tongue of the mobile home, and 0.82 m (2.7 ft) SSE of the most SE pole of the awnings of the mobile home. The bench mark is set 9 cm (0.3 ft) below ground level, crimped to the top of a stainless steel rod driven 14.6 m (48 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 3 of 4 Station ID: 8665167 PUBLICATION DATE: 10/30/2003 Name: HAMLIN SOUND SC NOAA Chart: 11521 Latitude: 32° 49.6' N ( 32.82670) USGS Quad: FORT MOULTRIE Longitude: 79° 47.2' W ( -79.78670) T I D A L D A T U M S Tidal datums at HAMLIN SOUND based on: LENGTH OF SERIES: 1 YEAR TIME PERIOD: April 1978 - March 1979 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 (07/19/1978) = 2.325 MEAN HIGHER HIGH WATER MHHW = 1.755 MEAN HIGH WATER MHW = 1.638 North American Vertical Datum NAVD88 = 0.974 MEAN SEA LEVEL MSL = 0.885 MEAN TIDE LEVEL MTL = 0.847 MEAN LOW WATER MLW = 0.057 MEAN LOWER LOW WATER MLLW = 0.000 LOWEST OBSERVED WATER LEVEL (01/24/1979) = -0.832 North American Vertical Datum (NAVD88) Bench Mark Elevation Information In METERS above: Stamping or Designation MLLW MHW 5167 A 1978 2.559 0.921 5167 G 1982 2.749 1.111 5167 H 1982 2.488 0.850
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 4 Station ID: 8665167 PUBLICATION DATE: 10/30/2003 Name: HAMLIN SOUND SC NOAA Chart: 11521 Latitude: 32° 49.6' N ( 32.82670) USGS Quad: FORT MOULTRIE Longitude: 79° 47.2' W ( -79.78670) 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.