U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 5 Station ID: 8665814 PUBLICATION DATE: 11/23/2005 Name: ASHEPOO RIVER AT 17 SC NOAA Chart: 11517 Latitude: 32° 44.6' N ( 32.74330) USGS Quad: Green Pond Longitude: 80° 33.4' W ( -80.55670) To reach the tidal bench marks from the intersection of U.S. Highway 17 and State Road 64 at Jacksonboro, proceed WSW on State Road 64 for 8.0 km (5.0 mi) to the road bridge over the Ashepoo River. The bench marks are on the west side of the Ashepoo River, along U.S. Highway 17, and on the bridge. The tide gage and staff were on the west side of the river, just south of the bridge, near the private boat landing owned by Mr. Smith (Smith's Landing). T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: 5814 A 1977 DESIGNATION: 866 5814 A TIDAL MONUMENTATION: Tidal Station disk VM#: 4236 AGENCY: National Ocean Survey (NOS) IDB PID#: CK3003 SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID: LATITUDE: 32° 44.6' N ( 32.74330) LONGITUDE: 80° 33.4' W ( -80.55670) The primary bench mark is a disk located at Smith's Landing, 29.23 m (96.0 ft) SE of bench mark 5814 B 1977, 17.37 m (57.0 ft) WNW of the centerline of the concrete boat landing, 16.46 m (54.0 ft) NNE of SCE&G power pole #205484 and 4 m (12 ft) SSW of the river bank. The bench mark is set at ground level, crimped to the top of a copper-clad steel rod driven 4.9 m (16 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: 8665814 PUBLICATION DATE: 11/23/2005 Name: ASHEPOO RIVER AT 17 SC NOAA Chart: 11517 Latitude: 32° 44.6' N ( 32.74330) USGS Quad: Green Pond Longitude: 80° 33.4' W ( -80.55670) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 5814 B 1977 DESIGNATION: 866 5814 B TIDAL MONUMENTATION: Tidal Station disk VM#: 4237 AGENCY: National Ocean Survey (NOS) IDB PID#: CK3002 SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID: LATITUDE: 32° 44.6' N ( 32.74330) LONGITUDE: 80° 33.4' W ( -80.55670) The bench mark is a disk located along U.S. Highway 17 at the utility pole closest to the Ashepoo River, 23.16 m (76.0 ft) NW of SCE&G power pole #205484, 22 m (72 ft) NE of a 1 m (2 ft) diameter pine tree, 20.57 m (67.5 ft) SSE of the centerline of U.S. highway 17, 18.59 m (61.0 ft) ESE of the SW corner of the bridge, and 1.89 m (6.2 ft) ESE of utility pole #4939. The bench mark is set at ground level, crimped to the top of an unspecified steel rod driven an unspecified depth, and surrounded by a kickblock. BENCH MARK STAMPING: 5814 G 1981 DESIGNATION: 866 5814 G TIDAL MONUMENTATION: Tidal Station disk VM#: 4238 AGENCY: National Ocean Survey (NOS) IDB PID#: CK3000 SETTING CLASSIFICATION: Concrete monument OPUS PID: LATITUDE: 32° 44.6' N ( 32.74330) LONGITUDE: 80° 33.4' W ( -80.55670) The bench mark is a disk set in the top of a concrete monument along U.S. Highway 17, 111 m (364 ft) SW of bench mark 5814 B 1977, 19 m (62 ft) SSE of the centerline of U.S. Highway 17, 1.43 m (4.7 ft) SW of telephone junction box #A79261, and 0.12 m (0.4 ft) above the ground.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 5 Station ID: 8665814 PUBLICATION DATE: 11/23/2005 Name: ASHEPOO RIVER AT 17 SC NOAA Chart: 11517 Latitude: 32° 44.6' N ( 32.74330) USGS Quad: Green Pond Longitude: 80° 33.4' W ( -80.55670) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 5814 H 1981 DESIGNATION: 866 5814 H TIDAL MONUMENTATION: Tidal Station disk VM#: 4239 AGENCY: National Ocean Survey (NOS) IDB PID#: CK3001 SETTING CLASSIFICATION: Concrete bridge abutment OPUS PID: LATITUDE: 32° 44.6' N ( 32.74330) LONGITUDE: 80° 33.4' W ( -80.55670) The bench mark is a disk set flush in the concrete bridge abutment of the U.S. Highway 17 bridge over the Ashepoo River, 5.58 m (18.3 ft) NNE of the centerline of U.S. Highway 17, 5.06 m (16.6 ft) ENE of a guy wire anchor to power pole #30PL18, 3.38 m (11.1 ft) SE of power pole #30PL18, and 0.55 m (1.8 ft) WNW of the SW corner of the bridge rail.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 5 Station ID: 8665814 PUBLICATION DATE: 11/23/2005 Name: ASHEPOO RIVER AT 17 SC NOAA Chart: 11517 Latitude: 32° 44.6' N ( 32.74330) USGS Quad: Green Pond Longitude: 80° 33.4' W ( -80.55670) T I D A L D A T U M S Tidal datums at ASHEPOO RIVER AT 17 based on: LENGTH OF SERIES: 6 MONTHS TIME PERIOD: May 1981 - October 1981 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 = 0.767 MEAN HIGH WATER MHW = 0.742 MEAN SEA LEVEL MSL = 0.479 MEAN TIDE LEVEL MTL = 0.412 North American Vertical Datum NAVD88 = 0.299 MEAN LOW WATER MLW = 0.083 MEAN LOWER LOW WATER MLLW = 0.000 North American Vertical Datum (NAVD88) Bench Mark Elevation Information In METERS above: Stamping or Designation MLLW MHW 5814 A 1977 1.864 1.122 5814 B 1977 1.843 1.101 5814 G 1981 1.964 1.222 5814 H 1981 3.876 3.134
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 5 Station ID: 8665814 PUBLICATION DATE: 11/23/2005 Name: ASHEPOO RIVER AT 17 SC NOAA Chart: 11517 Latitude: 32° 44.6' N ( 32.74330) USGS Quad: Green Pond Longitude: 80° 33.4' W ( -80.55670) 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.