U.S. DEPARTMENT OF COMMERCE
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National Ocean Service
Datums Page Page 1 of 7
Station ID: 8664941 PUBLICATION DATE: 09/20/2011
Name: SOUTH CAPERS ISLAND, CAPERS CREEK
SC
NOAA Chart: 11531 Latitude: 32° 51.4' N ( 32.85670)
USGS Quad: CAPERS INLET Longitude: 79° 42.4' W ( -79.70670)
To reach the tidal bench marks from the north end of Isle of Palms, proceed by
boat NE along the Intracoastal Waterway for about 4.5 km (2.8 statute mi) to the
SW end of Capers Island, near the junction of Capers Creek, Whiteside Creek, and
Toomers Creek. The bench marks are located on the north side of Old Dike Road
that leads from the SW end of Capers Island to the island interior. The tide
gage and staff were located at the seaward end of the pier at the SW end of the
island.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: C.C. NO 5 1975
DESIGNATION: 866 4941 C.C. TIDAL 5
MONUMENTATION: Survey disk VM#: 4116
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Unspecified steel rod OPUS PID:
LATITUDE: 32° 51.6' N ( 32.86000) LONGITUDE: 79° 42.4' W ( -79.70670)
The primary bench mark is a disk located 114 m (375 ft) east of the shore end of
a small wooden dock, directly in line with the dock and the centerline of Old
Dike Road, 19.02 m (62.4 ft) east of the center of the curve in Old Dike Road,
8.44 m (27.7 ft) east of a South Carolina Wildlife sign "Welcome to Capers
Island," 4.75 m (15.6 ft) NNW of a 0.37 m (1.2 ft) diameter laurel oak tree, and
0.24 m (0.8 ft) west of a steel witness post. The bench mark is set at ground
level, crimped to the top of a steel rod driven an unspecified depth 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 2 of 7
Station ID: 8664941 PUBLICATION DATE: 09/20/2011
Name: SOUTH CAPERS ISLAND, CAPERS CREEK
SC
NOAA Chart: 11531 Latitude: 32° 51.4' N ( 32.85670)
USGS Quad: CAPERS INLET Longitude: 79° 42.4' W ( -79.70670)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: C.C. NO 3 1975
DESIGNATION: 866 4941 C.C. TIDAL 3
MONUMENTATION: Survey disk VM#: 4114
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Copper pipe in concrete OPUS PID:
LATITUDE: 32° 51.6' N ( 32.86000) LONGITUDE: 79° 42.4' W ( -79.70670)
The bench mark is a disk set in the top of a 2-inch diameter copper pipe
surrounded by concrete located north of Old Dike Road on a thin strip of land
surrounded by marsh, 29.11 m (95.5 ft) north of the centerline of Old Dike Road,
28.19 m (92.5 ft) east of benchmark "Casper", and 0.64 m (2.1 ft) SW of a metal
witness post.
BENCH MARK STAMPING: C.C. NO 4 1975
DESIGNATION: 866 4941 C.C. TIDAL 4
MONUMENTATION: Survey disk VM#: 4115
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Unspecified steel rod OPUS PID:
LATITUDE: 32° 51.6' N ( 32.86000) LONGITUDE: 79° 42.4' W ( -79.70670)
The bench mark is a disk set in a palmetto grove, 22.40 m (73.5 ft) north of the
centerline of Old Dike Road, 20.18 m (66.2 ft) NNW of bench mark C.C. NO 5 1975,
and 0.67 m (2.2 ft) SW of a witness post. The bench mark is set 3 cm (0.1 ft)
below ground level, crimped to the top of a steel rod driven an unspecified
depth 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 7
Station ID: 8664941 PUBLICATION DATE: 09/20/2011
Name: SOUTH CAPERS ISLAND, CAPERS CREEK
SC
NOAA Chart: 11531 Latitude: 32° 51.4' N ( 32.85670)
USGS Quad: CAPERS INLET Longitude: 79° 42.4' W ( -79.70670)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: CAPERS
DESIGNATION: CAPERS
MONUMENTATION: Survey disk VM#: 4117
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: CJ0703
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 32° 51.5' N ( 32.85830) LONGITUDE: 79° 42.4' W ( -79.70670)
The bench mark is a disk set in a concrete monument located in a thin strip of
land surrounded by marsh, 70.84 m (232.4 ft) north of Old Dike Road, 23.22 m
(76.2 ft) NW of bench mark CAPERS 1, and 2.74 m (9.0 ft) east of a witness
post.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 7
Station ID: 8664941 PUBLICATION DATE: 09/20/2011
Name: SOUTH CAPERS ISLAND, CAPERS CREEK
SC
NOAA Chart: 11531 Latitude: 32° 51.4' N ( 32.85670)
USGS Quad: CAPERS INLET Longitude: 79° 42.4' W ( -79.70670)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1 CAPERS
DESIGNATION: CAPERS RM 1
MONUMENTATION: Reference Mark disk VM#: 4118
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: CJ1109
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 32° 51.6' N ( 32.86000) LONGITUDE: 79° 42.4' W ( -79.70670)
The bench mark is a disk set in a concrete monument located on a thin strip of
land surrounded by marsh, 51.82 m (170.0 ft) north of Old Dike Road, 3.60 m
(11.8 ft) east of a live 0.3 m (1 ft) diameter live oak tree, and 0.09 m (0.3
ft) SW of a witness post.
BENCH MARK STAMPING: 4941 F 2003
DESIGNATION: 866 4941 F
MONUMENTATION: Metal Rod VM#: 17562
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod in sleeve OPUS PID#: DM3223
LATITUDE: 32° 51.5' N ( 32.85899) LONGITUDE: 79° 42.4' W ( -79.70723)
The bench mark is located at the landward end of the pier at the SW end of South
Capers Island, 45.99 m (150.9 ft) NW of the NW corner of the pier, 2.13 m (7.0
ft) NE of a piling supporting a bulkhead, and 0.15 m (0.5 ft) south of a witness
post. The datum point is 9 cm (0.3 ft) below the ground, being the top of a
stainless steel rod driven 22.2 m (72.8 ft) in a sleeve enxtending to a depth of
0.9 m (3.0 ft) and encased in a NOS logo cap.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 7
Station ID: 8664941 PUBLICATION DATE: 09/20/2011
Name: SOUTH CAPERS ISLAND, CAPERS CREEK
SC
NOAA Chart: 11531 Latitude: 32° 51.4' N ( 32.85670)
USGS Quad: CAPERS INLET Longitude: 79° 42.4' W ( -79.70670)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 4941 G 2003
DESIGNATION: 866 4941 G
MONUMENTATION: Metal Rod VM#: 17563
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod in sleeve OPUS PID:
LATITUDE: 32° 51.5' N ( 32.85830) LONGITUDE: 79° 42.3' W ( -79.70500)
The bench mark located NE of the pier at the SW end of South Capers Islnad, up
the Dike Road set along the south edge of the road in a grassy area, 71.63 m
(235.0 ft) south of the welcome sign, 1.83 m (6.00 m) west of the centerline of
the Old Dike Road, and 0.18 m (0.6 ft) east of a witness post. The datum point
is 9 cm (0.3 ft) below ground, being the top of a stainless steel rod driven
23.5 m (77 ft) in a sleeve extending to a depth of 0.9 m (3.0 ft) and encased in
a NOS logo cap.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 7
Station ID: 8664941 PUBLICATION DATE: 09/20/2011
Name: SOUTH CAPERS ISLAND, CAPERS CREEK
SC
NOAA Chart: 11531 Latitude: 32° 51.4' N ( 32.85670)
USGS Quad: CAPERS INLET Longitude: 79° 42.4' W ( -79.70670)
T I D A L D A T U M S
Tidal datums at SOUTH CAPERS ISLAND, CAPERS CREEK based on:
LENGTH OF SERIES: 3 YEARS
TIME PERIOD: January 2005 - December 2007
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 (10/09/2006) = 2.294
MEAN HIGHER HIGH WATER MHHW = 1.625
MEAN HIGH WATER MHW = 1.507
MEAN SEA LEVEL MSL = 0.786
MEAN TIDE LEVEL MTL = 0.779
MEAN LOW WATER MLW = 0.051
MEAN LOWER LOW WATER MLLW = 0.000
LOWEST OBSERVED WATER LEVEL (03/17/1976) = -0.728
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
C.C. NO 5 1975 2.464 0.957
C.C. NO 3 1975 2.121 0.614
C.C. NO 4 1975 2.386 0.879
CAPERS 2.136 0.629
1 CAPERS 2.320 0.813
4941 F 2003 1.957 0.450
4941 G 2003 2.336 0.829
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 7 of 7
Station ID: 8664941 PUBLICATION DATE: 09/20/2011
Name: SOUTH CAPERS ISLAND, CAPERS CREEK
SC
NOAA Chart: 11531 Latitude: 32° 51.4' N ( 32.85670)
USGS Quad: CAPERS INLET Longitude: 79° 42.4' W ( -79.70670)
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.