U.S. DEPARTMENT OF COMMERCE
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National Ocean Service
Datums Page Page 1 of 5
Station ID: 8667633 PUBLICATION DATE: 12/15/2020
Name: CLARENDON PLANTATION, WHALE BR.
SC
NOAA Chart: 11519 Latitude: 32° 30.1' N ( 32.50250)
USGS Quad: SHELDON Longitude: 80° 47.0' W ( -80.78410)
To reach the tidal bench marks from the U.S. Highway 21 and the Seaboard
Railroad at Lobeco, proceed 6 km (4 mi) south on U.S. Highway 21 to the Grey
Hill Store, then 0.8 km (0.5 mi) west to the entrance to Clarendon Plantation,
bear right on the paved road and continue past the plantation entrance for 2.7
km (1.7 mi), turn left onto a dirt road bordering the north end of Clarendon
Plantations fenced-in property, continue on this dirt road for 0.3 km (0.2 mi),
bear right just before a boat ramp. The bench marks are in the area near the
boat ramp. The tide gage and staff were located on the northernmost dock of
Clarendon Plantation.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 7633 A 1980
DESIGNATION: 866 7633 A TIDAL
MONUMENTATION: Tidal Station disk VM#: 4371
AGENCY: National Ocean Survey/Service (NOS) IDB PID#: CK2205
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 32° 30.1' N ( 32.50169) LONGITUDE: 80° 47.0' W ( -80.78331)
The primary bench mark is 10.67 m (35.0 ft) SSE of the centerline of the walkway
to the nothernmost dock on Clarendon property, 3.66 m (12.0 ft) east of the edge
of the river bluff, 0.61 m (2.0 ft) SE of the westernmost fence post at the end
of a chain link fence, and 0.43 m (1.4 ft) west of a steel witness post. The
bench mark is crimped to a stainless steel rod driven 10 m (32 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: 8667633 PUBLICATION DATE: 12/15/2020
Name: CLARENDON PLANTATION, WHALE BR.
SC
NOAA Chart: 11519 Latitude: 32° 30.1' N ( 32.50250)
USGS Quad: SHELDON Longitude: 80° 47.0' W ( -80.78410)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 7633 C 2008
DESIGNATION: 866 7633 C
MONUMENTATION: Tidal Station disk VM#: 18591
AGENCY: National Ocean Survey/Service (NOS) IDB PID:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 32° 30.1' N ( 32.50169) LONGITUDE: 80° 47.0' W ( -80.78331)
The bench mark is a located 71.1 m (233.3 ft) SSE of bench mark 866 7633 A,
9.75 m (31.99 ft) NNW of the centerline of Clarenndon Plantation Road leading to
boat landing, 1.5 m (4.9 ft) north east of a 24" pine tree, and 0.46 m (1.51 ft)
west north west of a carsonite witness post. The bench mark is crimped to a
stainless steel rod driven 0.91 m (3.0 ft) into the ground, and encased in a
13-cm (5 in) PVC pipe and concrete kickblock.
BENCH MARK STAMPING: 7633 D 2008
DESIGNATION: 866 7633 D
MONUMENTATION: Tidal Station disk VM#: 18592
AGENCY: National Ocean Survey/Service (NOS) IDB PID:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 32° 30.1' N ( 32.50169) LONGITUDE: 80° 47.0' W ( -80.78331)
The bench mark is located 39.42 m (129.33 ft) north of bench mark 866 7633 TIDAL
4, 15.1 m (49.5 ft) south of a fence post holding the access road gate, 4.70 m
(15.42 ft) west of the centerline of the access road to the plantation from the
boat ramp, 4.00 m (13.12 ft) east of the river's bluff, and 2.85 m (9.35 ft)
south of a 0.5 m (1.6 ft) diameter pine treem. he bench mark is crimped to a
stainless steel rod driven to an unspecified depth to refusal, and encased in
PVC pipe and a concrete kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 8667633 PUBLICATION DATE: 12/15/2020
Name: CLARENDON PLANTATION, WHALE BR.
SC
NOAA Chart: 11519 Latitude: 32° 30.1' N ( 32.50250)
USGS Quad: SHELDON Longitude: 80° 47.0' W ( -80.78410)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 3 1934
DESIGNATION: 866 7633 TIDAL 3
MONUMENTATION: Tidal Station disk VM#: 18594
AGENCY: U.S. Geological Survey (USGS) IDB PID#: CK0911
SETTING CLASSIFICATION: Concrete OPUS PID:
LATITUDE: 32° 30.1' N ( 32.50169) LONGITUDE: 80° 46.9' W ( -80.78169)
The bench mark is set in concrete inside of an 8-inch pipe located 5.5 m (18.0
ft) south from the centerline of dim track road, 2.6 m (8.5 ft) south from a
metal fence line, 2.4 m (7.9 ft) west of a 7 ft (2.1 m) diameter oak tree, and
1.2 m (3.9 ft) east of a carsonite witness post.
BENCH MARK STAMPING: NO 4 1974
DESIGNATION: 866 7633 TIDAL 4
MONUMENTATION: Tidal Station disk VM#: 18595
AGENCY: National Ocean Survey/Service (NOS) IDB PID:
SETTING CLASSIFICATION: concrete monument OPUS PID:
LATITUDE: 32° 30.1' N ( 32.50100) LONGITUDE: 80° 46.9' W ( -80.78169)
The bench mark is set into a concrete monument located 48.5 m (159.1 ft) south
from metal access gate from boat ramp to plantation big house, 43.5 M (142.72
ft) north from the centerline of east end of pier to dock, and 3.0 m (9.8 ft)
east of River's Bluff.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 8667633 PUBLICATION DATE: 12/15/2020
Name: CLARENDON PLANTATION, WHALE BR.
SC
NOAA Chart: 11519 Latitude: 32° 30.1' N ( 32.50250)
USGS Quad: SHELDON Longitude: 80° 47.0' W ( -80.78410)
T I D A L D A T U M S
Tidal datums at CLARENDON PLANTATION, WHALE BR. based on:
LENGTH OF SERIES: 4 YEARS
TIME PERIOD: 01/2009-12/2009, 12/2010-11/2013
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8670870 FORT PULASKI, SAVANNAH RIVER
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
HIGHEST OBSERVED WATER LEVEL (06/24/2009) = 3.396
MEAN HIGHER HIGH WATER MHHW = 2.621
MEAN HIGH WATER MHW = 2.508
MEAN SEA LEVEL MSL = 1.463
MEAN TIDE LEVEL MTL = 1.285
MEAN LOW WATER MLW = 0.062
MEAN LOWER LOW WATER MLLW = 0.000
LOWEST OBSERVED WATER LEVEL (01/12/2009) = -0.826
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
7633 A 1980 5.650 3.142
7633 C 2008 5.579 3.071
7633 D 2008 4.990 2.482
NO 3 1934 5.175 2.667
NO 4 1974 5.346 2.838
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 8667633 PUBLICATION DATE: 12/15/2020
Name: CLARENDON PLANTATION, WHALE BR.
SC
NOAA Chart: 11519 Latitude: 32° 30.1' N ( 32.50250)
USGS Quad: SHELDON Longitude: 80° 47.0' W ( -80.78410)
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.