U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
PUBLICATION DATE: 05/02/1989
Station ID: 8668701 SUPERCEDED DATE: 04/21/2003
Name: PURRYSBURG LANDING, SAVANNAH RIVER
SOUTH CAROLINA
NOAA Chart: 11514 Latitude: 32° 18.2' N
USGS Quad: HARDEEVILLE Longitude: 81° 7.3' W
To reach the tidal bench marks from the intersection of U.S. Highway 17 and
State Highway 46 in Hardeeville, proceed NW on State Highway 46 for 0.3 mile
(0.5 km) to U.S. Highway 321, proceed straight through the intersection and onto
County Road S-27-31 for 2.2 miles (3.5 km), turn right onto County Road S-27-34
and go north for 0.4 mile (0.6 km) to the entrance of Purrysburg Fishing Camp,
turn left into the entrance and proceed 0.2 mile (0.3 km) to the camp. The
bench marks are near the bait shop and along the road leading to the fishing
camp. The tide gage and staff were located on the camps dock behind the bait
shop and house.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 8701 D 1979
MONUMENTATION: Survey Disk VM#: 4518
AGENCY: PID#: CK1994
SETTING CLASSIFICATION: Stainless Steel Rod
The bench mark is at the NW corner of the intersection of County Road S-27-34
and the dirt road leading to Purrysburg Fishing Camp, 60.1 feet (18.3 m) NNE of
a 1.0 foot (0.3 m) diameter pine tree with a sign Drive Slow Or Stay The Hell
Out, 38.6 feet (11.8 m) west of County Road S-27-34, 29.2 feet (8.9 m) NNW of a
stop sign, 19.6 feet (6.0 m) NNE of the centerline of the dirt road, and 5.5
feet (1.7 m) east of a 2.0-foot (0.6 m) diameter pine tree. The bench mark is
0.2 foot (0.1 m) below ground level, crimped to the top of a stainless steel rod
driven 30 feet (9 m) 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
PUBLICATION DATE: 05/02/1989
Station ID: 8668701 SUPERCEDED DATE: 04/21/2003
Name: PURRYSBURG LANDING, SAVANNAH RIVER
SOUTH CAROLINA
NOAA Chart: 11514 Latitude: 32° 18.2' N
USGS Quad: HARDEEVILLE Longitude: 81° 7.3' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 8701 E 1979
MONUMENTATION: Survey Disk VM#: 4519
AGENCY: PID#: CK1993
SETTING CLASSIFICATION: Stainless Steel Rod
The bench mark is on the east side of County Road S-27-34, south of the dirt
road leading to Purrysburg Fishing Camp, 201.3 feet (61.4 m) SSE of Bench Mark
8701 D 1979, 72.0 feet (21.9 m) NE of telephone junction box #EE 6-126-36, 32.0
feet (9.8 m) ESE of the centerline of County Road S-27-34, and 7.5 feet (2.3 m)
north of a 1-foot (0.3 m) diameter maple tree. The bench mark is 0.2 foot (0.1
m) below ground level crimped to a stainless steel rod driven 30 feet (9 m) to
refusal, and encased in a 4-inch PVC pipe and concrete kickblock.
BENCH MARK STAMPING: 8701 F 1979
MONUMENTATION: Survey Disk VM#: 4520
AGENCY: PID#: CK1992
SETTING CLASSIFICATION: Stainless Steel Rod
The bench mark is on the west side of County Road S-27-34, south of the dirt
road leading to Purrysburg Fishing Camp, 180.0 feet (54.9 m) SSW of Bench Mark
8701 E 1979, 120.1 feet (36.6 m) south of telephone junction box #EE-6-126-136,
34.0 feet (10.4 m) west of the centerline of County Road S-27-34, 9.9 feet (3.0
m) SW of a witness sign on a 2.0 foot (0.6 m) diameter oak tree. The bench mark
is 0.1 foot (0.03 m) below ground level, crimped to a stainless steel rod driven
32 feet (10 m) 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 5
PUBLICATION DATE: 05/02/1989
Station ID: 8668701 SUPERCEDED DATE: 04/21/2003
Name: PURRYSBURG LANDING, SAVANNAH RIVER
SOUTH CAROLINA
NOAA Chart: 11514 Latitude: 32° 18.2' N
USGS Quad: HARDEEVILLE Longitude: 81° 7.3' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 8701 G 1981
MONUMENTATION: Survey Disk VM#: 4521
AGENCY: PID#: CK1996
SETTING CLASSIFICATION: Concrete Monument
The bench mark is set flush in a concrete monument, approximately 76 feet (23
m) ESE of the river edge, 59.1 feet (18.0 m) WNW of the service pole with light
#E-88-76-5PPH-630, 45.5 feet (13.9 m) SSW of the SW corner of the porch of the
red house belonging to Mr. Curtis, 41.0 feet (12.5 m) south of a 4.2 foot (1.3
m) diameter oak tree, 10.5 feet (3.2 m) east of a 1.5 foot (0.5 m) tall concrete
bait box, and at ground level.
BENCH MARK STAMPING: 8701 H 1981
MONUMENTATION: Survey Disk VM#: 4522
AGENCY: PID#: CK1995
SETTING CLASSIFICATION: Concrete Monument
The bench mark is set flush in a concrete monument, 200.0 feet (70.0 m) north of
the centerline of the dirt entrance road, 115.6 feet (35.2 m) NNE of a service
pole with a light, 25.0 feet (7.6 m) NNW of a metal shed, 6.5 feet (2.0 m) east
of the concrete block garden wall, and at ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
PUBLICATION DATE: 05/02/1989
Station ID: 8668701 SUPERCEDED DATE: 04/21/2003
Name: PURRYSBURG LANDING, SAVANNAH RIVER
SOUTH CAROLINA
NOAA Chart: 11514 Latitude: 32° 18.2' N
USGS Quad: HARDEEVILLE Longitude: 81° 7.3' W
T I D A L D A T U M S
Tidal datums at PURRYSBURG LANDING, SAVANNAH RIVER based on:
LENGTH OF SERIES: 6 MONTHS
TIME PERIOD: JULY - DECEMBER 1980
TIDAL EPOCH: 1960-1978
CONTROL TIDE STATION: 8670870 FORT PULASKI, GA
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET:
HIGHEST OBSERVED WATER LEVEL (04/08/1980) = 8.36
MEAN HIGHER HIGH WATER MHHW = 3.29
MEAN HIGH WATER MHW = 3.11
MEAN TIDE LEVEL MTL = 1.60
MEAN LOW WATER MLW = 0.10
MEAN LOWER LOW WATER MLLW = 0.00
LOWEST OBSERVED WATER LEVEL (08/07/1980) = -1.00
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In FEET above:
Stamping or Designation MLLW MHW
8701 D 1979 15.09 11.98
8701 E 1979 14.10 10.99
8701 F 1979 15.39 12.28
8701 G 1981 15.38 12.27
8701 H 1981 16.42 13.31
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
PUBLICATION DATE: 05/02/1989
Station ID: 8668701 SUPERCEDED DATE: 04/21/2003
Name: PURRYSBURG LANDING, SAVANNAH RIVER
SOUTH CAROLINA
NOAA Chart: 11514 Latitude: 32° 18.2' N
USGS Quad: HARDEEVILLE Longitude: 81° 7.3' 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.