U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 8666616 PUBLICATION DATE: 03/09/2004
Name: SOUTH EDISTO RIVER AT DAWHOO RIVER
SC
NOAA Chart: 11517 Latitude: 32° 39.4' N ( 32.65670)
USGS Quad: FENWICK Longitude: 80° 23.5' W ( -80.39170)
To reach the tidal bench marks from the intersection of U.S. Highway 17 and
State Highway 162, proceed south on State Highway 163 for 17.9 km (11.1 mi) to
the intersection of State Highway 164, then bear left and proceed SW on State
Highway 164 for 3.9 km (2.4 mi) to State Highway 174, then proceed straight
through the intersection and continue 5.1 km (3.2 mi) to the end of the
pavement, then continue straight for 1.6 km (1.0 mi) on the dirt road to State
Road S-10-38, then bear left past the entrance to Hutton Plantation and proceed
0.5 km (0.3 mi), then bear left past the entrance to Willtown Bluff and continue
0.8 km (0.5 mi) to Willtown Bluff Boat Landing. By boat, travel 4.8 km (3.0 mi)
south on South Edisto River to the gage site on the north bank of a turn in the
river. The bench marks are located on a small dike, formerly the site of a
fishing camp. The tide gage and staff were located 0.5 km (0.3 mi) west of the
mouth of Dawhoo River, 61 m (200 ft) east of the mouth of a small creek, and 30
m (100 ft) from berm line. NOTE: This station can only be reached by boat.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 6616 A 1979
DESIGNATION: 866 6616 A TIDAL
MONUMENTATION: Tidal Station disk VM#: 4324
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 32° 39.4' N ( 32.65670) LONGITUDE: 80° 23.5' W ( -80.39170)
The primary bench mark is a disk located at the southern end of the westernmost
dike, 14.45 m (47.4 ft) SSW of bench mark 6616 B 1979, 8.81 m (28.9 ft) SSE of a
0.61 m (2.0 ft) diameter cypress tree on the east bank of the small creek, and
0.79 m (2.6 ft) NW of a witness post. The bench mark is crimped to the top of a
stainless steel rod driven 8.2 m (27 ft) to refusal, encased in a PVC pipe and
concrete kickblock, and at ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 8666616 PUBLICATION DATE: 03/09/2004
Name: SOUTH EDISTO RIVER AT DAWHOO RIVER
SC
NOAA Chart: 11517 Latitude: 32° 39.4' N ( 32.65670)
USGS Quad: FENWICK Longitude: 80° 23.5' W ( -80.39170)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 6616 B 1979
DESIGNATION: 866 6616 B TIDAL
MONUMENTATION: Tidal Station disk VM#: 4325
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 32° 39.4' N ( 32.65670) LONGITUDE: 80° 23.5' W ( -80.39170)
The bench mark is a disk located at the western end of a small dike near the
steep creek bank where many bricks are scattered about, 10.12 m (33.2 ft) SSW of
a 0.91 m (3.0 ft) diameter cypress tree, 7.16 m (23.5 ft) NNE of a 0.61 m (2.0
ft) diameter cypress tree, 2.26 m (7.4 ft) SE of the creek bank, and 1.19 m (3.9
ft) south of a witness post. The bench mark is crimped to the top of a
stainless steel rod driven 8.2 m (27 ft) to refusal, encased in a PVC pipe and
concrete kickblock, and at ground level.
BENCH MARK STAMPING: 6616 C 1979
DESIGNATION: 866 6616 C TIDAL
MONUMENTATION: Tidal Station disk VM#: 4326
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 32° 39.4' N ( 32.65670) LONGITUDE: 80° 23.5' W ( -80.39170)
The bench mark is a disk located at the easternmost of two dikes running
north-south, 12.89 m (42.3 ft) south of bench mark HOS 2 1933, 5 m (16 ft) south
of a 9 cm (0.3 ft) diameter water oak tree, 0.98 m (3.2 ft) north of a 9 cm (0.3
ft) diamter water oak tree, and 0.49 m (1.6 ft) SW of a witness post. The bench
mark is crimped to the top of a stainless steel rod driven 7.3 m (24 ft) to
refusal, encased in a PVC pipe and concrete kickblock, and at ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 8666616 PUBLICATION DATE: 03/09/2004
Name: SOUTH EDISTO RIVER AT DAWHOO RIVER
SC
NOAA Chart: 11517 Latitude: 32° 39.4' N ( 32.65670)
USGS Quad: FENWICK Longitude: 80° 23.5' W ( -80.39170)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: HOS 1 1933
DESIGNATION: 866 6616 HOS 1
MONUMENTATION: Reference Mark disk VM#: 4327
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 32° 39.4' N ( 32.65670) LONGITUDE: 80° 23.5' W ( -80.39170)
The bench mark is a disk set flush in a concrete monument on a small dike
running east-west, 12.74 m (41.8 ft) east of bench mark 6616 B 1979, 6 m (20 ft)
west of a 0.3 m (1.0 ft) diameter cedar tree, 1.58 m (5.2 ft) north of the south
edge of the dike, 1.25 m (4.1 ft) south of the north edge of the dike, and 6 cm
(0.2 ft) above ground level.
BENCH MARK STAMPING: HOS 2 1933
DESIGNATION: 866 6616 HOS 2
MONUMENTATION: Reference Mark disk VM#: 4328
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 32° 39.4' N ( 32.65670) LONGITUDE: 80° 23.5' W ( -80.39170)
The bench mark is set flush in a concrete monument at the junction of two dikes
running east-west and north-south, 10.49 m (34.4 ft) east of bench mark HOS 1
1933, 4.24 m (13.9 ft) east of a 0.3 m (1.0 ft) diameter cedar tree, 2.96 m (9.7
ft) NE of the south edge of the dike, 1.80 m (5.9 ft) NE of the south edge of
the dike, and 6 cm (0.2 ft) above ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 8666616 PUBLICATION DATE: 03/09/2004
Name: SOUTH EDISTO RIVER AT DAWHOO RIVER
SC
NOAA Chart: 11517 Latitude: 32° 39.4' N ( 32.65670)
USGS Quad: FENWICK Longitude: 80° 23.5' W ( -80.39170)
D A T U M S
Datums at SOUTH EDISTO RIVER AT DAWHOO RIVER based on:
LENGTH OF SERIES: 5 MONTHS
TIME PERIOD: April 1979 - August 1979
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8670870 FORT PULASKI, SAVANNAH RIVER
Elevations of datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 2.024
MEAN HIGH WATER MHW = 1.939
MEAN SEA LEVEL MSL = 1.136
MEAN TIDE LEVEL MTL = 1.002
MEAN LOW WATER MLW = 0.065
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 8666616 PUBLICATION DATE: 03/09/2004
Name: SOUTH EDISTO RIVER AT DAWHOO RIVER
SC
NOAA Chart: 11517 Latitude: 32° 39.4' N ( 32.65670)
USGS Quad: FENWICK Longitude: 80° 23.5' W ( -80.39170)
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.