U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 1 of 6
Station ID: 8662799 PUBLICATION DATE: 04/21/2003
Name: US HIGHWAY 17, SOUTH SANTEE RIVER
SOUTH CAROLINA
NOAA Chart: 11531 Latitude: 33ø 11.1' N
USGS Quad: SANTEE Longitude: 79ø 24.4' W
To reach the tidal bench marks from the Cooper River Bridge in Charleston,
proceed north on U.S. Highway 17 for 71 km (44 mi) 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 were 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
DESIGNATION: V 124
MONUMENTATION: Bench Mark disk VM#: 599
AGENCY: US Coast and Geodetic Survey (USC&GS) PID#: DD0688
SETTING CLASSIFICATION: Concrete bridge abutment
The primary bench mark is a disk set flush in the concrete bridge abutment at
the SW end of the southbound lanes of US Highway 17, 29.26 m (96.0 ft) west of
bench mark 2799 G 1978, 10.24 m (33.6 ft) west of the John T. Stevens Memorial
Bridge Monument, 4.21 m (13.8 ft) west of the centerline of U.S. Highway 17
South, 0.70 m (2.3 ft) SE of the SW bridge railing of the southbound lane, and
0.3 m (1 ft) above road level.
BENCH MARK STAMPING: SS NO 2 1975
DESIGNATION: 866 2799 TIDAL SS 2
MONUMENTATION: Tidal Station disk VM#: 600
AGENCY: National Ocean Survey (NOS) PID#: DD0947
SETTING CLASSIFICATION: Copper-clad steel rod
The bench mark is a disk located 0.24 km (0.15 mi) SW of the south end of the
bridge, 26.33 m (86.4 ft) WNW of the centerline of U.S. Highway 17 South, 8.38 m
(27.5 ft) NNE of a 0.76 m (2.5 ft) diameter pine tree, 26.2 m (86.0 ft) NW of
the centerline of the southbound lanes of the highway, 5.67 m (18.6 ft) WNW of
the tree line, 4.15 m (13.6 ft) SSW of a 0.46 m (1.5 ft) diameter oak tree, 0.61
m (2.0 ft) NE of a witness post, and 0.30 m (1.0 ft) above the level of the
highway. The bench mark is crimped to a copper-clad steel rod driven 6.1 m (20
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 6
Station ID: 8662799 PUBLICATION DATE: 04/21/2003
Name: US HIGHWAY 17, SOUTH SANTEE RIVER
SOUTH CAROLINA
NOAA Chart: 11531 Latitude: 33ø 11.1' N
USGS Quad: SANTEE Longitude: 79ø 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
DESIGNATION: 866 2799 TIDAL SS 3
MONUMENTATION: Tidal Station disk VM#: 601
AGENCY: National Ocean Survey (NOS) PID#: DD0949
SETTING CLASSIFICATION: Copper-clad steel rod
The bench mark is a disk located WSW of the south end of the U.S. Highway 17
John T. Stevens Memorial Bridge, 44.81 m (147.0 ft) north of the centerline of
the southbound lanes of the highway, 11.37 m (37.3 ft) west of a set of twin
pine trees, 10.67 m (35.0 ft) north of the centerline of the abandoned road bed
of the old U.S. Highway 17, and 0.79 m (2.6 ft) east of a witness post with
sign. The bench mark is set 0.30 m (1.0 ft) below the level of the abandoned
highway, crimped to a copper-clad steel rod driven 6.1 m (20 ft) to refusal, and
encased in a 4-inch PVC pipe and concrete kickblock.
BENCH MARK STAMPING: S.C. GEOD. S. CT 103 RESET 1976
DESIGNATION: CT 103 RESET
MONUMENTATION: Bench Mark disk VM#: 602
AGENCY: National Geodetic Survey (NGS) PID#: DD0950
SETTING CLASSIFICATION: Concrete monument
The bench mark is a disk set flush in a concrete monument on an embankment on
the south side of U.S. Highway 17 North, 34.44 m (113.0 ft) NNE of a concrete
marker delineating the highway right-of-way, 17.59 m (57.7 ft) SE of the
centerline of U.S. Highway 17 North, 0.49 m (1.6 ft) SSW of a witness post with
sign, and 0.06 m (0.20 ft) above the level of the highway.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 6
Station ID: 8662799 PUBLICATION DATE: 04/21/2003
Name: US HIGHWAY 17, SOUTH SANTEE RIVER
SOUTH CAROLINA
NOAA Chart: 11531 Latitude: 33ø 11.1' N
USGS Quad: SANTEE Longitude: 79ø 24.4' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 2799 G 1978
DESIGNATION: 866 2799 G TIDAL
MONUMENTATION: Tidal Station disk VM#: 603
AGENCY: National Ocean Survey (NOS) PID#: DD0946
SETTING CLASSIFICATION: Bridge abutment
The bench mark is a disk set flush in the SE bridge abutment of the northbound
lanes of U.S. Highway 17, 29.26 m (96.0 ft) east of bench mark V 124 1962, 19.66
m (64.5 ft) east of the John T. Stevens Memorial Bridge Monument, 6.71 m (22.0
ft) SE of the centerline of U.S. Highway 17 North, 2.13 m (7.0 ft) NNW of a sign
marking the Georgetown County line and South Santee River, 0.24 m (0.8 ft) east
of the SE bridge railing of the northbound bridge and 0.30 m (1.0 ft) above the
level of the highway.
BENCH MARK STAMPING: HORZ 022 033 1981
DESIGNATION: 022 033
MONUMENTATION: Survey disk VM#: 604
AGENCY: South Carolina Geodetic Survey (SCGS) PID#: DD2400
SETTING CLASSIFICATION: Concrete monument
The bench mark is a disk 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, 9.30 m (30.5 ft) SE of the centerline of the southbound lanes
of U.S. Highway 17, 8.99 m (29.5 ft) NW of the centerline of the northbound
lanes of the highway, 1.74 m (5.7 ft) east of a metal guard rail along the
southbound lane of the highway, 1.43 m (4.7 ft) west of the guard rail along the
northbound lane of the highway, 0.52 m (1.7 ft) NNE of a witness post with sign,
0.30 m (1.0 ft) below the level of the highway, and 0.09 m (0.3 ft) above ground
level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 6
Station ID: 8662799 PUBLICATION DATE: 04/21/2003
Name: US HIGHWAY 17, SOUTH SANTEE RIVER
SOUTH CAROLINA
NOAA Chart: 11531 Latitude: 33ø 11.1' N
USGS Quad: SANTEE Longitude: 79ø 24.4' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 022 033 RM 1 1981
DESIGNATION: 022 033 RM 1
MONUMENTATION: Survey disk VM#: 605
AGENCY: South Carolina Geodetic Survey (SCGS) PID#: DD2401
SETTING CLASSIFICATION: Concrete monument
The bench mark is a disk set flush in a concrete monument in the grass median
strip between the northbound/southbound lanes of U.S. Highway 17, at the NE end
of the bridge, 9.20 m (30.2 ft) SE of the centerline of the southound lanes of
the highway, 8.99 m (29.5 ft) NW of the centerline of the northbound lanes of
the highway, 2.77 m (9.1 ft) east of the metal guard rail along the southbond
lane of the highway, 2.29 m (7.5 ft) west of the guard rail along the northbound
lane of the highway, 0.40 m (1.3 ft) east of a witness post with sign and 0.30 m
(1.0 ft) below the level of the highway.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 6
Station ID: 8662799 PUBLICATION DATE: 04/21/2003
Name: US HIGHWAY 17, SOUTH SANTEE RIVER
SOUTH CAROLINA
NOAA Chart: 11531 Latitude: 33ø 11.1' N
USGS Quad: SANTEE Longitude: 79ø 24.4' W
T I D A L D A T U M S
Tidal datums at US HIGHWAY 17, SOUTH SANTEE RIVER based on:
LENGTH OF SERIES: 12 Years
TIME PERIOD: January 1977 - December 1988
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 (03/12/1987) = 2.107
MEAN HIGHER HIGH WATER (MHHW) = 1.376
MEAN HIGH WATER (MHW) = 1.289
MEAN SEA LEVEL (MSL) = 0.686
NORTH AMERICAN VERTICAL DATUM-1988 (NAVD) = 0.686
MEAN TIDE LEVEL (MTL) = 0.670
MEAN LOW WATER (MLW) = 0.050
MEAN LOWER LOW WATER (MLLW) = 0.000
LOWEST OBSERVED WATER LEVEL (04/06/1982) = -0.520
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
V 124 1962 7.234 5.945
SS NO 2 1975 7.189 5.900
SS NO 3 1975 6.232 4.943
S.C. GEOD. S. CT 103 RESET 1976 7.358 6.069
2799 G 1978 7.240 5.951
HORZ 022 033 1981 4.900 3.611
022 033 RM 1 1981 5.065 3.776
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 6
Station ID: 8662799 PUBLICATION DATE: 04/21/2003
Name: US HIGHWAY 17, SOUTH SANTEE RIVER
SOUTH CAROLINA
NOAA Chart: 11531 Latitude: 33ø 11.1' N
USGS Quad: SANTEE Longitude: 79ø 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 (NAVD 88).
NGVD 29 is a fixed datum adopted as a national standard geodetic reference for
heights but is now considered superseded. NGVD 29 is sometimes referred to as
Sea Level Datum of 1929 or as Mean Sea Level on some early issues of Geological
Survey Topographic Quads. NGVD 29 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 NGVD 29 are available from the National
Geodetic Survey (NGS) data base via the World Wide Web at
National Geodetic Survey.
NAVD 88 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. NAVD 88 replaces NGVD 29 as the national
standard geodetic reference for heights. Bench mark elevations relative to
NAVD 88 are available from NGS through the World Wide Web at
National Geodetic Survey.
NGVD 29 and NAVD 88 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 NAVD 88 elevation is shown on the Elevations of Tidal Datums Table Referred
to MLLW only when two or more of the bench marks listed have NAVD 88 elevations.
The NAVD 88 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, NAVD 88 bench mark elevations computed indirectly from the tidal
datums elevation table may differ slightly from NAVD 88 elevations listed for
each bench mark in the NGS database.