U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 8664699 PUBLICATION DATE: 12/09/2022
Name: NORTH CHARLESTON, ASHLEY RIVER
SC
NOAA Chart: 11524 Latitude: 32° 54.0' N ( 32.90028)
USGS Quad: LANDON Longitude: 80° 7.1' W ( -80.11750)
To reach the tide station from the intersection of US-17 ALT N and SC-642, head
east on SC-642 / Dorchester Rd for 15.3 km (9.5 mi) to the intersection with
Park Forest Pkwy and turn right. Proceed south on Park Forest Pkwy for 1.4 km
(0.9 mi) to the entrance for the Summer's Bend on the Ashley community and
continue straight on Cardinal Crest Bluff road for another 0.5 km (0.3 mi) to
the end of the road. Proceed by foot to the gated entrance for the Summer's
Bend on the Ashley community dock. The tide station is located halfway down on
the south side of the community dock. The bench marks are located with the
Summer's Bend on the Ashley property, along Park Forest Pkwy, SC-642, and Ashley
Phosphate Rd.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 4699 A 2022
DESIGNATION: 866 4699 A
MONUMENTATION: Flange-encased Rod VM#: 24190
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: OPUS PID#: BBHS44
LATITUDE: 32° 54.0' N ( 32.90056) LONGITUDE: 80° 7.0' W ( -80.11672)
The bench mark is a rod located 17.3 m (56.8 ft) south of the centerline of
Child's Cove at the intersection with Cardinal Crest Bluff, 6.1 m (20.0 ft) NNE
of a carsonite witness post set in the tall ornamental grasses, 5.1 m (16.7 ft)
SE of the approximate centerline of Cardinal Crest Bluff, and 2.5 m (8.2 ft) NW
of the edge west edge of the pond.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 8664699 PUBLICATION DATE: 12/09/2022
Name: NORTH CHARLESTON, ASHLEY RIVER
SC
NOAA Chart: 11524 Latitude: 32° 54.0' N ( 32.90028)
USGS Quad: LANDON Longitude: 80° 7.1' W ( -80.11750)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 4699 B 2022
DESIGNATION: 866 4699 B
MONUMENTATION: Flange-encased Rod VM#: 24191
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: OPUS PID#: BBHS45
LATITUDE: 32° 54.7' N ( 32.91208) LONGITUDE: 80° 6.6' W ( -80.10992)
The bench mark is a rod located 37.1 m (121.7 ft) east of the north post for the
"Welcome to park forest" sign, 20.1 m (65.9 ft) SE of the northern edge of the
parking lot near the playground, 10.4 m (34.1 ft) NW of the approximate
centerline of the westbound Park Forest Parkway lane, and 1.0 m (3.3 ft) SE of
the SE edge of a parking block on the south side of the parking lot.
BENCH MARK STAMPING: 4699 C 2022
DESIGNATION: 866 4699 C
MONUMENTATION: Tidal Station disk VM#: 24192
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Overhead sign base OPUS PID:
LATITUDE: 32° 54.8' N ( 32.91369) LONGITUDE: 80° 6.4' W ( -80.10747)
The bench mark is a brass disk set flush with the concrete foundation located
2.9 m (9.5 ft) NE of the center of the sidewalk, 3.2 m (10.5 ft) south of the
southern edge of the curved curb for the turning lane onto Dorchester Road, 2.5
m (8.2 ft) NW of the NW edge of a large power line support tower, and 2.2 m (7.2
ft) west of the Park Forest PKWY/Dorchester Road street sign.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 8664699 PUBLICATION DATE: 12/09/2022
Name: NORTH CHARLESTON, ASHLEY RIVER
SC
NOAA Chart: 11524 Latitude: 32° 54.0' N ( 32.90028)
USGS Quad: LANDON Longitude: 80° 7.1' W ( -80.11750)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: VERT 18 015 1983
DESIGNATION: 18 015
MONUMENTATION: Survey disk VM#: 24193
AGENCY: South Carolina Geodetic Survey (SCGS) IDB PID#:
SETTING CLASSIFICATION: OPUS PID:
LATITUDE: 32° 54.5' N ( 32.90756) LONGITUDE: 80° 5.8' W ( -80.09681)
The bench mark is a disk set on a concrete post recessed 9 cm (4 inches) and
level with the highway, 45.0 m (147.6 ft) west of a fire hydrant on the east
side of the fire department driveway, 24.5 m (80.4 ft) SSW of the centerline of
the SE bound lanes of the highway, 11.7 m (38.4 ft) ESE of the north corner of
the fire department, and 8.9 m (29.2 ft) south of a power pole number 215671
with two guy wires and three transformers.
BENCH MARK STAMPING: VERT 18 013 1983
DESIGNATION: 18 013
MONUMENTATION: Survey disk VM#: 24194
AGENCY: South Carolina Geodetic Survey (SCGS) IDB PID#:
SETTING CLASSIFICATION: OPUS PID:
LATITUDE: 32° 55.3' N ( 32.92242) LONGITUDE: 80° 5.8' W ( -80.09603)
The mark is a disk set in a concrete post recessed 15 cm (6 inches) below grade,
25.1 m (82.3 ft) north of the center of the westbound lanes of the highway, 9.0
m (29.5 ft) west of a 2.5-foot double-trunked maple tree, 1.5 m (4.9 ft) NE of
the NE corner of a concrete sidewalk in front of the building, and 1.4 m (4.6
ft) SE of the SE corner of the building.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 8664699 PUBLICATION DATE: 12/09/2022
Name: NORTH CHARLESTON, ASHLEY RIVER
SC
NOAA Chart: 11524 Latitude: 32° 54.0' N ( 32.90028)
USGS Quad: LANDON Longitude: 80° 7.1' W ( -80.11750)
T I D A L D A T U M S
Tidal datums at NORTH CHARLESTON, ASHLEY RIVER based on:
LENGTH OF SERIES: 4 MONTHS
TIME PERIOD: March 2022 - June 2022
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 = 1.955
MEAN HIGH WATER MHW = 1.870
MEAN SEA LEVEL MSL = 1.120
North American Vertical Datum NAVD88 = 1.087
MEAN TIDE LEVEL MTL = 0.969
MEAN LOW WATER MLW = 0.068
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
4699 A 2022 3.094 1.224
4699 B 2022 6.819 4.949
4699 C 2022 8.993 7.123
VERT 18 015 1983 9.061 7.191
VERT 18 013 1983 9.498 7.628
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 8664699 PUBLICATION DATE: 12/09/2022
Name: NORTH CHARLESTON, ASHLEY RIVER
SC
NOAA Chart: 11524 Latitude: 32° 54.0' N ( 32.90028)
USGS Quad: LANDON Longitude: 80° 7.1' W ( -80.11750)
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.