U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 6
Station ID: 8666467 PUBLICATION DATE: 02/05/2004
Name: FOLLY RIVER, NORTH
SC
NOAA Chart: 11525 Latitude: 32° 40.2' N ( 32.67000)
USGS Quad: JAMES ISLAND Longitude: 79° 55.0' W ( -79.91670)
To reach the tidal bench marks from the intersection of Center Street and Ashley
Avenue East in downtown Folly Beach, proceed NE on Ashley Avenue East for 2.9 km
(1.8 mi) to East 13th Street, then turn left and proceed north on East 13th
Street for 0.2 km (0.1 mi) to Tabby Drive, then turn left and proceed west on
Tabby Drive to the second house on the north (right) side of the street. The
bench marks are located on Ashley Avenue East, along East 13th Street, and near
Tabby Drive. The tide gage and staff were located on the pier behind the house
at 1212 Tabby Drive, owned by Dr. Heinsohn.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 6467 A 1976
DESIGNATION: 866 6467 A TIDAL
MONUMENTATION: Tidal Station disk VM#: 4312
AGENCY: National Ocean Survey (NOS) IDB PID#: CJ0462
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID:
LATITUDE: 32° 40.1' N ( 32.66830) LONGITUDE: 79° 54.9' W ( -79.91500)
The primary bench mark is a disk located near a stand of trees at the western
boundary of 1212 Tabby Drive, 77.72 m (255.0 ft) SSE of the end of a concrete
walkway to the dock, 27.74 m (91.0 ft) west of the SW corner of a concrete boat
ramp, 21.21 m (69.6 ft) NW of the NW corner of a brick chimney, 17.80 m (58.4
ft) NW of the NW corner of the house, and 2.01 m (6.6 ft) east of a 0.3 m (1 ft)
diameter pine tree. The bench mark is set at ground level, crimped to the top
of a copper-clad steel rod driven 12.2 m (40 ft) 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 6
Station ID: 8666467 PUBLICATION DATE: 02/05/2004
Name: FOLLY RIVER, NORTH
SC
NOAA Chart: 11525 Latitude: 32° 40.2' N ( 32.67000)
USGS Quad: JAMES ISLAND Longitude: 79° 55.0' W ( -79.91670)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 6467 B 1976
DESIGNATION: 866 6467 B TIDAL
MONUMENTATION: Tidal Station disk VM#: 4313
AGENCY: National Ocean Survey (NOS) IDB PID#: CJ0461
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID:
LATITUDE: 32° 40.1' N ( 32.66830) LONGITUDE: 79° 54.9' W ( -79.91500)
The bench mark is a disk located north of the intersection of Tabby Drive and
East 13th Street, 10.27 m (33.7 ft) east of the centerline of the concrete
driveway at 1214 Tabby Drive, 8.84 m (29.0 ft) north of the centerline of Tabby
Drive, 4.24 m (13.9 ft) NW of a fire hydrant, and 1.10 m (3.6 ft) NW of utility
pole #93967. The bench mark is set 6 cm (0.2 ft) above ground level, crimped to
the top of a copper-clad steel rod driven 12.2 m (40 ft) to refusal, and encased
in a PVC pipe and concrete kickblock.
BENCH MARK STAMPING: 6467 C 1976
DESIGNATION: 866 6467 C TIDAL
MONUMENTATION: Tidal Station disk VM#: 4314
AGENCY: National Ocean Survey (NOS) IDB PID#: CJ0460
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 32° 40.1' N ( 32.66830) LONGITUDE: 79° 54.9' W ( -79.91500)
The bench mark is a disk on the west side of East 13th Street, 10.55 m (34.6 ft)
NNW of the centerline of the most northern driveway on the west side of East
13th Street, 8.60 m (28.2 ft) SW of the centerline of East 13th Street, 0.61 m
(2.0 ft) west of utility pole #174759 with a witness sign, 0.61 m (2.0 ft) NE of
the corner post of a 1 m (4 ft) high chainlink fence, and 3 cm (0.1 ft) above
ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 6
Station ID: 8666467 PUBLICATION DATE: 02/05/2004
Name: FOLLY RIVER, NORTH
SC
NOAA Chart: 11525 Latitude: 32° 40.2' N ( 32.67000)
USGS Quad: JAMES ISLAND Longitude: 79° 55.0' W ( -79.91670)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 6467 D 1976
DESIGNATION: 866 6467 D TIDAL
MONUMENTATION: Tidal Station disk VM#: 4315
AGENCY: National Ocean Survey (NOS) IDB PID#: CJ0458
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID:
LATITUDE: 32° 40.0' N ( 32.66670) LONGITUDE: 79° 54.9' W ( -79.91500)
The bench mark is a disk located midway between bench mark 6467 C 1976 and
Ashley Avenue East on the west side of East 13th Street, 21.49 m (70.5 ft) SW of
a cinderblock wall, 11.13 m (36.5 ft) NE of the centerline of a concrete
driveway on the west side of East 13th Street, 6.55 m (21.5 ft) SW of the
centerline of East 13th Street, and 1.74 m (5.7 ft) east of utility pole #93963.
The bench mark is set at ground level, crimped to the top of a copper-clad
steel rod driven 12.2 m (40 ft) to refusal, and encased in a PVC pipe and
concrete kickblock.
BENCH MARK STAMPING: 6467 E 1976
DESIGNATION: 866 6467 E TIDAL
MONUMENTATION: Tidal Station disk VM#: 4316
AGENCY: National Ocean Survey (NOS) IDB PID#: CJ0457
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 32° 40.0' N ( 32.66670) LONGITUDE: 79° 54.9' W ( -79.91500)
The bench mark is a disk south of the intersection of East 13th Street and
Ashley Avenue East, 20.39 m (66.9 ft) east of utility pole #27767, 5.82 m (19.1
ft) SSE of the centerline of Ashley Avenue East, 5.21 m (17.1 ft) west of the
corner post of the house at 1301 Ashley Avenue East, 0.61 m (2.0 ft) NE of a
fire hydrant, and at ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 6
Station ID: 8666467 PUBLICATION DATE: 02/05/2004
Name: FOLLY RIVER, NORTH
SC
NOAA Chart: 11525 Latitude: 32° 40.2' N ( 32.67000)
USGS Quad: JAMES ISLAND Longitude: 79° 55.0' W ( -79.91670)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 6467 F 1983
DESIGNATION: 866 6467 F TIDAL
MONUMENTATION: Tidal Station disk VM#: 4317
AGENCY: National Ocean Survey (NOS) IDB PID#: CJ0459
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 32° 40.1' N ( 32.66830) LONGITUDE: 79° 54.8' W ( -79.91330)
The bench mark is a disk set near bench mark 6467 C 1976, 42.09 m (138.1 ft) SSE
of the centerline of Tabby Drive, 8.23 m (27.0 ft) WSW of the centerline of East
13th Street, 1.22 m (4.0 ft) ESE of utility pole #174759 with a witness sign,
0.91 m (3.0 ft) ENE of a chain link fence, and at ground level.
BENCH MARK STAMPING: 6467 G 1983
DESIGNATION: 866 6467 G TIDAL
MONUMENTATION: Tidal Station disk VM#: 4318
AGENCY: National Ocean Survey (NOS) IDB PID#: CJ0456
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 32° 40.0' N ( 32.66670) LONGITUDE: 79° 54.8' W ( -79.91330)
The bench mark is a disk set near the intersection of Ashley Avenue East and
East 13th Street, 14.69 m (48.2 ft) ENE of utility pole #93962, 5.85 m (19.2 ft)
SSE of the centerline of Ashley Avenue East, 0.61 m (2.0 ft) WNW of a fire
hydrant, and at ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 6
Station ID: 8666467 PUBLICATION DATE: 02/05/2004
Name: FOLLY RIVER, NORTH
SC
NOAA Chart: 11525 Latitude: 32° 40.2' N ( 32.67000)
USGS Quad: JAMES ISLAND Longitude: 79° 55.0' W ( -79.91670)
T I D A L D A T U M S
Tidal datums at FOLLY RIVER, NORTH based on:
LENGTH OF SERIES: 1 YEAR
TIME PERIOD: February 1977 - January 1978
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 (06/01/1977) = 2.388
MEAN HIGHER HIGH WATER MHHW = 1.813
MEAN HIGH WATER MHW = 1.696
North American Vertical Datum NAVD88 = 1.005
MEAN SEA LEVEL MSL = 0.919
MEAN TIDE LEVEL MTL = 0.876
MEAN LOW WATER MLW = 0.056
MEAN LOWER LOW WATER MLLW = 0.000
LOWEST OBSERVED WATER LEVEL (12/10/1977) = -0.682
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
6467 A 1976 2.503 0.807
6467 B 1976 2.499 0.803
6467 C 1976 2.367 0.671
6467 D 1976 2.463 0.767
6467 E 1976 3.318 1.622
6467 F 1983 2.406 0.710
6467 G 1983 3.289 1.593
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 6
Station ID: 8666467 PUBLICATION DATE: 02/05/2004
Name: FOLLY RIVER, NORTH
SC
NOAA Chart: 11525 Latitude: 32° 40.2' N ( 32.67000)
USGS Quad: JAMES ISLAND Longitude: 79° 55.0' W ( -79.91670)
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.