U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 9
Station ID: 8662746 PUBLICATION DATE: 05/06/2003
Name: WINYAH BAY, SOUTH ISLAND PLANTATION
SC
NOAA Chart: 11532 Latitude: 33° 14.1' N ( 33.23500)
USGS Quad: SANTEE POINT Longitude: 79° 12.2' W ( -79.20330)
To reach the tidal bench marks from North Santee River Bridge on U.S. Highway
17, proceed north on U.S. Highway 17 for 1.0 km (0.6 mi) to State Highway
S-22-30. Turn right onto State Highway S-22-30 and go east for 7.7 km (4.8 mi)
to the end of the paved road. Turn left and continue north on State Highway
S-22-30 for 4.5 km (2.8 mi) to Route S-22-18. Turn right onto Route S-22-18 and
go east for 1.1 km (0.7 mi) to a ferry crossing the Intracoastal Waterway. Take
the ferry and continue 7.2 km (4.5 mi) along the dirt road (passing the entrance
to an estate on South Island). Turn left at the entrance past garages and sheds
and go north for 0.8 km (0.5 mi) to the Coast Guard Station. The bench marks
are along the dirt road leading to the Coast Guard Station. The tide gauge and
staff were on the north end of the Coast Guard pier, east of Bench Mark W.B. NO.
1 1975.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: WB NO 1 1975
DESIGNATION: 866 2746 TIDAL WB 1
MONUMENTATION: Tidal Station disk VM#: 586
AGENCY: National Ocean Survey (NOS) IDB PID#: DD0887
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID:
LATITUDE: 33° 14.1' N ( 33.23500) LONGITUDE: 79° 12.2' W ( -79.20330)
The primary bench mark is a disk located near the base of the Coast Guard pier,
29.08 m (95.4 ft) east of the NE corner of the maintenance garage, 13.1 m (43
ft) NW of the NW corner of a wooden boat ramp, 9 m (28 ft) east of the center of
the road, 1.68 m (5.5 ft) SE of the SW corner of a walkway to a dock, and 0.6 m
(2 ft) south of the south edge of a walkway to a dock. The bench mark is
crimped to a copper-clad steel rod driven 11.0 m (36 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 9
Station ID: 8662746 PUBLICATION DATE: 05/06/2003
Name: WINYAH BAY, SOUTH ISLAND PLANTATION
SC
NOAA Chart: 11532 Latitude: 33° 14.1' N ( 33.23500)
USGS Quad: SANTEE POINT Longitude: 79° 12.2' W ( -79.20330)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: WB NO 2 1975
DESIGNATION: 866 2746 TIDAL WB 2
MONUMENTATION: Tidal Station disk VM#: 587
AGENCY: National Ocean Survey (NOS) IDB PID#: DD0884
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID:
LATITUDE: 33° 14.1' N ( 33.23500) LONGITUDE: 79° 12.3' W ( -79.20500)
The bench mark is a disk located 21 m (69 ft) WSW of bench mark WB NO 1 1975, 12
m (39 ft) SW of the center of the road, 12 m (39 ft) east of the SE corner of
the maintenance garage, and 1 m (3 ft) east of a power pole with a meter and
light. The bench mark is crimped to the top of a copper-clad steel rod driven
11.0 m (36 ft) to refusal, and encased in a 4-inch PVC pipe and concrete
kickblock.
BENCH MARK STAMPING: WB NO 4 1975
DESIGNATION: 866 2746 TIDAL WB 4
MONUMENTATION: Tidal Station disk VM#: 589
AGENCY: National Ocean Survey (NOS) IDB PID#: DD0882
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID:
LATITUDE: 33° 14.1' N ( 33.23500) LONGITUDE: 79° 12.3' W ( -79.20500)
The bench mark is a disk located 65.3 m (214.3 ft) south of bench mark WB NO 1
1975, 17.83 m (58.5 ft) SE of the centerline of the dirt road, 16.15 m (53.0 ft)
NW of the north end of a damaged wooden bulkhead, and 0.30 m (1.0 ft) north of a
witness post. The bench mark is crimped to the top of a copper-clad steel rod
driven 11.0 m (36 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 9
Station ID: 8662746 PUBLICATION DATE: 05/06/2003
Name: WINYAH BAY, SOUTH ISLAND PLANTATION
SC
NOAA Chart: 11532 Latitude: 33° 14.1' N ( 33.23500)
USGS Quad: SANTEE POINT Longitude: 79° 12.2' W ( -79.20330)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: WB NO 5 1975
DESIGNATION: 866 2746 TIDAL WB 5
MONUMENTATION: Tidal Station disk VM#: 590
AGENCY: National Ocean Survey (NOS) IDB PID#: DD0881
SETTING CLASSIFICATION: Copper Pipe OPUS PID:
LATITUDE: 33° 14.1' N ( 33.23500) LONGITUDE: 79° 12.3' W ( -79.20500)
The bench mark is a disk braized to a 1.2 m (4.0 ft) long copper pipe surrounded
by soil-crete, located near the edge of the woods at the back of the corner of
an open field, 66 m (216 ft) west of bench mark WB NO 4 1975, 36.73 m (120.5 ft)
WNW of the centerline of the dirt road, 1.19 m (3.9 ft) SW of an unnumbered
power pole, 0.3 m (1 ft) NE of a witness post, and 0.06 m (0.2 ft) above ground.
BENCH MARK STAMPING: 2746 G 1978
DESIGNATION: 866 2746 G
MONUMENTATION: Tidal Station disk VM#: 591
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Galvanized steel rod OPUS PID:
LATITUDE: 33° 14.1' N ( 33.23500) LONGITUDE: 79° 12.2' W ( -79.20330)
The bench mark is a disk located on the east side of the dirt road leading to
the gage site, 46 m (150 ft) SSE of bench mark WB NO 5 1975, 45.26 (148.5 ft) SE
of a power pole on the west side of the road, 10.1 m (33 ft) NE of the
easternmost cedar tree with a cross cut on its north side, 8.84 m (29.0 ft) SSE
of the centerline of the dirt road, and 0.61 m (2.0 ft) north of a witness post.
The bench mark is set 0.1 m (0.3 ft) below ground level, crimped to the top of
a stainless steel rod driven 7.6 m (25 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 9
Station ID: 8662746 PUBLICATION DATE: 05/06/2003
Name: WINYAH BAY, SOUTH ISLAND PLANTATION
SC
NOAA Chart: 11532 Latitude: 33° 14.1' N ( 33.23500)
USGS Quad: SANTEE POINT Longitude: 79° 12.2' W ( -79.20330)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 2746 J 1981
DESIGNATION: 866 2746 J
MONUMENTATION: Tidal Station disk VM#: 592
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 33° 14.1' N ( 33.23500) LONGITUDE: 79° 12.2' W ( -79.20330)
The bench mark is a disk set in concrete monument located 111.0 m (364.2 ft) NNW
of bench mark 2746 K 1981, 41.18 m (135.1 ft) SW of the SW corner of a white
concrete block house, 6.22 m (20.4 ft) west of the centerline of the dirt road
leading to the gage site, 1.83 m (6.0 ft) west of a 0.37 m (1.2 ft) diameter
palmetto tree, and 1.04 m (3.4 ft) NW of a witness post with sign.
BENCH MARK STAMPING: 2746 K 1981
DESIGNATION: 866 2746 K
MONUMENTATION: Tidal Station disk VM#: 593
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 33° 14.1' N ( 33.23500) LONGITUDE: 79° 12.2' W ( -79.20330)
The bench mark is a disk set in concrete monument located 93.3 m (306.2 ft)
north of the north corner of a green barn, 16.03 m (52.6 ft) ESE of the
centerline of the dirt road leading to the gage site, 14.63 m (48.0 ft) NNE of a
0.37 m (1.2 ft) diameter palmetto tree, 6.40 m (21.0 ft) south of a 0.37 m (1.2
ft) diameter magnolia tree, and 0.98 m (3.2 ft) east of a witness post with
sign.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 9
Station ID: 8662746 PUBLICATION DATE: 05/06/2003
Name: WINYAH BAY, SOUTH ISLAND PLANTATION
SC
NOAA Chart: 11532 Latitude: 33° 14.1' N ( 33.23500)
USGS Quad: SANTEE POINT Longitude: 79° 12.2' W ( -79.20330)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: AZ MK 022 024 1981
DESIGNATION: 022 024 AZ MK
MONUMENTATION: Azimuth Mark disk VM#: 594
AGENCY: South Carolina Geodetic Survey (SCGS) IDB PID#: DD2905
SETTING CLASSIFICATION: Concrete monument OPUS PID#: DD2905
LATITUDE: 33° 13.7' N ( 33.22830) LONGITUDE: 79° 12.3' W ( -79.20500)
The bench mark is a disk set in a concrete monument located at a telephone pole
near the entrance to the Tom Yawkey Wildlife Center, 16.67 m (54.7 ft) WNW of
the center of the brass plaque commemorating the Tom Yawkey Wildlife Center,
7.74 m (25.4 ft) north of the center of the easternmost 2 m x 2 m (6 ft x 6 ft)
picket fence post, 5.8 m (19 ft) SSW of the centerline of the dirt road leading
to the main gates of the Wildlife Center, 1.68 m (5.5 ft) NE of a metal witness
post with sign, and 1.34 m (4.4 ft) NE of telephone junction box P112 located at
the base of a telephone pole.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 9
Station ID: 8662746 PUBLICATION DATE: 05/06/2003
Name: WINYAH BAY, SOUTH ISLAND PLANTATION
SC
NOAA Chart: 11532 Latitude: 33° 14.1' N ( 33.23500)
USGS Quad: SANTEE POINT Longitude: 79° 12.2' W ( -79.20330)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: H 137 1979
DESIGNATION: H 137
MONUMENTATION: Flange-encased Rod VM#: 595
AGENCY: National Geodetic Survey (NGS) IDB PID#: DD0885
SETTING CLASSIFICATION: Stainless steel rod OPUS PID#: DD0885
LATITUDE: 33° 14.1' N ( 33.23500) LONGITUDE: 79° 12.3' W ( -79.20500)
The bench mark is a flange encased rod located near the Coast Guard maintenance
garage, 29.11 m (95.5 ft) west of bench mark WB NO 1 1975, 27.83 m (91.3 ft)
west of the NW corner of the pier, 19.63 m (64.4 ft) NNW of bench mark WB NO 2
1975, 12.13 m (39.8 ft) south of a gas pump, 4.02 m (13.2 ft) north of the NE
corner of the garage, and 0.42 m (1.4 ft) south of a witness post. The datum
point is the top of a stainless steel rod driven to a depth of 12.5 m (41 ft),
and encased in a 5-inch NGS logo cap.
BENCH MARK STAMPING: WB 17
DESIGNATION: 866 2746 WB 17
MONUMENTATION: Survey disk VM#: 597
AGENCY: US Army Corps of Engineers (USE) IDB PID#:
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID:
LATITUDE: 33° 14.1' N ( 33.23500) LONGITUDE: 79° 12.2' W ( -79.20330)
The bench mark is a disk located on the Coast Guard property, 18.65 m (61.2 ft)
NE of the NE corner of the maintenance garage, 16.76 m (55.0 ft) NW of the NW
end of the wooden pier, 10.97 m (36.0 ft) east of a gas pump, and 0.90 m (3.0
ft) SE of a witness post. The bench mark is crimped to the top of a copper-clad
steel rod driven to an unspecified depth, and encased in a PVC pipe and concrete
kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 7 of 9
Station ID: 8662746 PUBLICATION DATE: 05/06/2003
Name: WINYAH BAY, SOUTH ISLAND PLANTATION
SC
NOAA Chart: 11532 Latitude: 33° 14.1' N ( 33.23500)
USGS Quad: SANTEE POINT Longitude: 79° 12.2' W ( -79.20330)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 2746 L 1989
DESIGNATION: 866 2746 L
MONUMENTATION: Tidal Station disk VM#: 598
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 33° 14.1' N ( 33.23500) LONGITUDE: 79° 12.2' W ( -79.20330)
The bench mark is a disk located on the Star of South Carolina property near a
corrugated steel building, 46.73 m (153.3 ft) NW of the SW cornerstone of the
northernmost cinderblock wall, 25.91 m (85.0 ft) NNE of the NE corner of the
corrugated steel building, 8.75 m (28.7 ft) west of the centerline of a dirt
road, and 0.46 m (1.5 ft) west of a witness post. The bench mark is crimped to
the top of a stainless steel rod, driven to unspecified depth.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 8 of 9
Station ID: 8662746 PUBLICATION DATE: 05/06/2003
Name: WINYAH BAY, SOUTH ISLAND PLANTATION
SC
NOAA Chart: 11532 Latitude: 33° 14.1' N ( 33.23500)
USGS Quad: SANTEE POINT Longitude: 79° 12.2' W ( -79.20330)
T I D A L D A T U M S
Tidal datums at WINYAH BAY, SOUTH ISLAND PLANTATION based on:
LENGTH OF SERIES: 17 YEARS
TIME PERIOD: January 1979 - December 1995
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 (09/22/1989) = 2.812
MEAN HIGHER HIGH WATER MHHW = 1.305
MEAN HIGH WATER MHW = 1.212
North American Vertical Datum NAVD88 = 0.675
MEAN TIDE LEVEL MTL = 0.631
MEAN SEA LEVEL MSL = 0.624
MEAN LOW WATER MLW = 0.050
MEAN LOWER LOW WATER MLLW = 0.000
LOWEST OBSERVED WATER LEVEL (03/13/1993) = -1.123
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
WB NO 1 1975 1.891 0.679
WB NO 2 1975 2.019 0.807
WB NO 4 1975 1.776 0.564
WB NO 5 1975 1.420 0.208
2746 G 1978 1.769 0.557
2746 J 1981 1.443 0.231
2746 K 1981 2.344 1.132
AZ MK 022 024 1981 1.271 0.059
H 137 1979 1.625 0.413
WB 17 1.751 0.539
2746 L 1989 1.596 0.384
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 9 of 9
Station ID: 8662746 PUBLICATION DATE: 05/06/2003
Name: WINYAH BAY, SOUTH ISLAND PLANTATION
SC
NOAA Chart: 11532 Latitude: 33° 14.1' N ( 33.23500)
USGS Quad: SANTEE POINT Longitude: 79° 12.2' W ( -79.20330)
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.