U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 6
PUBLICATION DATE: 09/20/1989
Station ID: 8662799 SUPERCEDED DATE: 04/21/2003
Name: SOUTH SANTEE BRIDGE AT U.S. 17, SOUTH SANTEE RIVER
SOUTH CAROLINA
NOAA Chart: 11511 Latitude: 33° 11.1' N
USGS Quad: SANTEE Longitude: 79° 24.4' W
To reach the tidal bench marks from Cooper River Bridge in Charleston, proceed
north on U.S. Highway 17 for 44 miles (71 km) to the John T. Stevens Memorial
Bridge crossing South Santee River. The bench marks are along the northbound
and southbound lanes of U.S. Highway 17. The gage and staff are on a dock under
the SW end of the southbound lane of U.S. Highway 17.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: V 124 1962
MONUMENTATION: Survey Disk VM#: 599
AGENCY: PID#: DD0688
SETTING CLASSIFICATION: Concrete Abutment
The bench mark is set flush in the concrete bridge abutment at the SW end of the
southbound bridge, 96.0 feet (29.3 m) west of Bench Mark 2799 G 1978, 33.6 feet
(10.2 m) west of the John T. Stevens Memorial Bridge Monument, 13.8 feet (4.2 m)
west of the centerline of U.S. Highway 17 South, 2.3 feet (0.7 m) SE of the SW
bridge railing of the southbound lane, and 1.0 foot (0.3 m) above road level.
BENCH MARK STAMPING: SS NO 2 1975
MONUMENTATION: Survey Disk VM#: 600
AGENCY: PID#: DD0947
SETTING CLASSIFICATION: Copper-clad Steel Rod
The bench mark is 0.15 mile (0.24 km) SW of the south end of the bridge, 86.4
feet (26.3 m) WNW of the centerline of U.S. Highway 17 South, 27.5 feet (8.4
m) NNE of a 2.5-foot (0.8 m) diameter pine tree, 18.6 feet (5.7 m) WNW of the
tree line, 13.6 feet (4.1 m) SSW of a 1.5-foot (0.5 m) diameter oak tree, and
2.0 feet (0.6 m) east of a witness post. The bench mark is crimped to a
copper-clad steel rod driven 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 6
PUBLICATION DATE: 09/20/1989
Station ID: 8662799 SUPERCEDED DATE: 04/21/2003
Name: SOUTH SANTEE BRIDGE AT U.S. 17, SOUTH SANTEE RIVER
SOUTH CAROLINA
NOAA Chart: 11511 Latitude: 33° 11.1' N
USGS Quad: SANTEE Longitude: 79° 24.4' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: SS NO 3 1975
MONUMENTATION: Survey Disk VM#: 601
AGENCY: PID#: DD0949
SETTING CLASSIFICATION: Copper-clad Steel Rod
The bench mark is WSW of the south end of the bridge, 37.3 feet (11.4 m) west of
a set of twin pine trees, 35.0 feet (10.7 m) north of the centerline of the
abandoned road bed of old U.S. Highway 17, and 2.6 feet (0.8 m) east of a
witness post with sign. The bench mark is at ground level, crimped to a
copper-clad steel rod driven to refusal, and encased in a 4-inch PVC pipe and
concrete kickblock.
BENCH MARK STAMPING: S.C. GEOD.S. CT 103 RESET 1976
MONUMENTATION: Survey Disk VM#: 602
AGENCY: PID#: DD0950
SETTING CLASSIFICATION: Concrete Monument
The bench mark is set flush in a concrete monument on an embankment on the south
side of U.S. Highway 17 North, 113.0 feet (34.4 m) NNE of a concrete marker
delineating the highway right-of-way, 58.0 feet (17.7 m) ESE of the centerline
of U.S. Highway 17 North, 1.6 feet (0.5 m) SSW of a witness post with sign, and
0.3 foot (0.1 m) above ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 6
PUBLICATION DATE: 09/20/1989
Station ID: 8662799 SUPERCEDED DATE: 04/21/2003
Name: SOUTH SANTEE BRIDGE AT U.S. 17, SOUTH SANTEE RIVER
SOUTH CAROLINA
NOAA Chart: 11511 Latitude: 33° 11.1' N
USGS Quad: SANTEE Longitude: 79° 24.4' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 2799 G 1978
MONUMENTATION: Survey Disk VM#: 603
AGENCY: PID#: DD0946
SETTING CLASSIFICATION: Concrete Bridge Abutment
The bench mark is set flush in the SE bridge abutment of the northbound bridge
of U.S. Highway 17, 96.0 feet (29.3 m) east of Bench Mark V 124 1962, 64.5 feet
(19.7 m) east of the John T. Stevens Memorial Bridge Monument, 24.5 feet (7.5
m) east of the centerline of U.S. Highway 17 North, 7.0 feet (2.1 m) NNW of a
sign marking the Georgetown County line and South Santee River, and 0.8 foot
(0.2 m) east of the SE bridge railing of the northbound bridge.
BENCH MARK STAMPING: HORZ 022 033 1981
MONUMENTATION: Survey Disk VM#: 604
AGENCY: PID#: DD2400
SETTING CLASSIFICATION: Concrete Monument
The bench mark is set flush in a concrete monument in the grass median strip
between the northbound/southbound lanes of U.S. Highway 17, at the east end of
the bridge, 30.9 feet (9.4 m) ESE of the centerline of U.S. Highway 17 South,
25.9 feet (7.9 m) NNW of Bench Mark RM 1 022 033 1981, 5.7 feet (1.7 m) east of
a metal guard rail along the southbound lane of the highway, 4.7 feet (1.4
m) west of the guard rail along the northbound lane of the highway, and 1.7 feet
(0.5 m) NNE of a witness post with sign.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 6
PUBLICATION DATE: 09/20/1989
Station ID: 8662799 SUPERCEDED DATE: 04/21/2003
Name: SOUTH SANTEE BRIDGE AT U.S. 17, SOUTH SANTEE RIVER
SOUTH CAROLINA
NOAA Chart: 11511 Latitude: 33° 11.1' N
USGS Quad: SANTEE Longitude: 79° 24.4' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: RM1 022 033 1981
MONUMENTATION: Survey Disk VM#: 605
AGENCY: PID#: DD2401
SETTING CLASSIFICATION: Concrete Monument
The bench mark is set flush in a concrete monument in the grass median strip
between the northbound/southbound lanes of U.S. Highway 17, at the east end of
the bridge, 31.1 feet (9.5 m) ESE of the centerline of U.S. Highway 17 South,
9.1 feet (2.8 m) east of the metal guard rail along the southbond lane of the
highway, 7.5 feet (2.3 m) west of the guard rail along the northbound lane of
the highway, and 1.3 feet (0.4 m) east of a witness post with sign.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 6
PUBLICATION DATE: 09/20/1989
Station ID: 8662799 SUPERCEDED DATE: 04/21/2003
Name: SOUTH SANTEE BRIDGE AT U.S. 17, SOUTH SANTEE RIVER
SOUTH CAROLINA
NOAA Chart: 11511 Latitude: 33° 11.1' N
USGS Quad: SANTEE Longitude: 79° 24.4' W
T I D A L D A T U M S
Tidal datums at SOUTH SANTEE BRIDGE AT U.S. 17, SOUTH SANTEE RIVER based on:
LENGTH OF SERIES: 12 YEARS
TIME PERIOD: 1977-1988
TIDAL EPOCH: 1960-1978
CONTROL TIDE STATION: 8665530 CHARLESTON
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET:
HIGHEST OBSERVED WATER LEVEL (03/12/1987) = 7.18
MEAN HIGHER HIGH WATER MHHW = 4.54
MEAN HIGH WATER MHW = 4.27
MEAN TIDE LEVEL MTL = 2.22
MEAN LOW WATER MLW = 0.17
MEAN LOWER LOW WATER MLLW = 0.00
LOWEST OBSERVED WATER LEVEL (04/06/1982) = -1.44
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In FEET above:
Stamping or Designation MLLW MHW
V 124 1962 24.00 19.73
SS NO 2 1975 23.85 19.58
SS NO 3 1975 20.71 16.44
S.C. GEOD.S. CT 103 RESET 1976 24.41 20.14
2799 G 1978 24.02 19.75
HORZ 022 033 1981 16.37 12.10
RM1 022 033 1981 16.89 12.62
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 6
PUBLICATION DATE: 09/20/1989
Station ID: 8662799 SUPERCEDED DATE: 04/21/2003
Name: SOUTH SANTEE BRIDGE AT U.S. 17, SOUTH SANTEE RIVER
SOUTH CAROLINA
NOAA Chart: 11511 Latitude: 33° 11.1' N
USGS Quad: SANTEE Longitude: 79° 24.4' W
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 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.