Bench Mark Sheet for 8662549, SOUTH ISLAND FERRY, WINYAH BAY SC

Superseded Epoch

Large map location marker Station Location
Small red map location marker Published bench mark
Small blue map location marker Unpublished bench mark

Bench mark positions only appear on the map if their coordinates in the CO-OPS database are at the precision of degrees/minutes/seconds/and tenths of seconds. If the coordinates are less precise, the mark will not appear.

Printable version

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  6

                                                                                
Station ID: 8662549                         PUBLICATION DATE:  02/05/2004
Name:       SOUTH ISLAND FERRY, WINYAH BAY                    
            SC
NOAA Chart: 11532                           Latitude:   33° 15.1' N (  33.25170)
USGS Quad:  GEORGETOWN SOUTH                Longitude:  79° 16.1' W ( -79.26830)


To reach the tidal bench marks from the north end of the North Santee Bridge at
U.S. Highway 17, proceed north on Highway 17 for 1.0 km (0.6 mi) to State Road
S-22-30 (North Santee River Road), then right and proceed east on State Road
S-22-30 for 7.7 km (4.8 mi) to a dirt road leading to Annadale Plantation, then
bear left and continue on the paved road (still State Road S-22-30) for 4.5 km
(2.8 mi) to State Road S-22-18, then turn right onto State Road S-22-18 for 1.1
km (0.7 mi) to the ferry across the Intracoastal Waterway.  The bench marks are
near the ferry landing.  The tide gage and staff were on a dock just north of
the ferry landing.


                         T I D A L   B E N C H   M A R K S


                 PRIMARY BENCH MARK STAMPING:  2549 A 1976
                         DESIGNATION:          866 2549 A TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         3934
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  DD0868
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   33° 15.1' N (  33.25170)          LONGITUDE:  79° 16.1' W ( -79.26830)


The primary bench mark is a disk located next to the green wooden ferry
attendants watch shed near a utility pole and chimney, 9.60 m (31.5 ft) south of
a 0.3 m (1 ft) diameter pine tree near the edge of the marsh, 7.74 m (25.4 ft)
east of the center of a dock, 1.10 m (3.6 ft) SE of the utility pole with
witness sign, and 0.79 m (2.6 ft) ENE of the southeastern-most corner of the
ferry attendants watch shed.  The bench mark is set at ground level, crimped to
the top of a copper-clad steel rod driven 9.8 m (32 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: 8662549                         PUBLICATION DATE:  02/05/2004
Name:       SOUTH ISLAND FERRY, WINYAH BAY                    
            SC
NOAA Chart: 11532                           Latitude:   33° 15.1' N (  33.25170)
USGS Quad:  GEORGETOWN SOUTH                Longitude:  79° 16.1' W ( -79.26830)


                         T I D A L   B E N C H   M A R K S


                         BENCH MARK STAMPING:  BM 1 1935
                         DESIGNATION:          866 2549 TIDAL 1

MONUMENTATION:           Tidal Station disk                    VM#:         3933
AGENCY:                  US Coast & Geodetic Survey
                         (USC&GS)                                 IDB PID#:  DD0871
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   33° 15.0' N (  33.25000)          LONGITUDE:  79° 16.0' W ( -79.26670)


The bench mark is a disk set in a concrete monument, 32.10 m (105.3 ft) ESE of
bench mark 2549 C 1976, 10.27 m (33.7 ft) west of utility pole #U.S. Coast Guard
32, 9.20 m (30.2 ft) NNE of utility pole #40-5-A, 7 m (23 ft) SW of the
centerline of the dirt road leading to the ferry landing, and 0.21 m (0.7 ft)
above ground level.  



                         BENCH MARK STAMPING:  2549 B 1976
                         DESIGNATION:          866 2549 B TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         3935
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  DD0869
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   33° 15.1' N (  33.25170)          LONGITUDE:  79° 16.0' W ( -79.26670)


The bench mark is a disk located north of the dirt road leading to the ferry, 61
m (201 ft) east of bench mark 2549 A 1976, 22.19 m (72.8 ft) NNE of the
centerline of the dirt road, 3.87 m (12.7 ft) ENE of a 0.61 m (2.0 ft) diameter
pine tree, and 1.43 m (4.7 ft) NW of a utility pole with witness post.  The
bench mark is set at ground level, crimped to the top of a copper-clad steel rod
driven 9.8 m (32 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  3 of  6

                                                                                
Station ID: 8662549                         PUBLICATION DATE:  02/05/2004
Name:       SOUTH ISLAND FERRY, WINYAH BAY                    
            SC
NOAA Chart: 11532                           Latitude:   33° 15.1' N (  33.25170)
USGS Quad:  GEORGETOWN SOUTH                Longitude:  79° 16.1' W ( -79.26830)


                         T I D A L   B E N C H   M A R K S


                         BENCH MARK STAMPING:  2549 C 1976
                         DESIGNATION:          866 2549 C TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         3936
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  DD0870
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   33° 15.0' N (  33.25000)          LONGITUDE:  79° 16.0' W ( -79.26670)


The bench mark is a disk located near the green cinder block ferry attendants
house, 37 m (120 ft) south of bench mark 2549 B 1976, 10.91 m (35.8 ft) SE of
the NE corner of the ferry attendants house, 9.63 m (31.6 ft) SW of the
centerline of the dirt road, 3.75 m (12.3 ft) NW of the centerline of a drainage
ditch running perpendicular to the dirt road, and 1.52 m (5.0 ft) north of a
utility pole with witness sign and meter.  The bench mark is set at ground
level, crimped to the top of a copper-clad steel rod driven 9.8 m (32 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  4 of  6

                                                                                
Station ID: 8662549                         PUBLICATION DATE:  02/05/2004
Name:       SOUTH ISLAND FERRY, WINYAH BAY                    
            SC
NOAA Chart: 11532                           Latitude:   33° 15.1' N (  33.25170)
USGS Quad:  GEORGETOWN SOUTH                Longitude:  79° 16.1' W ( -79.26830)


                         T I D A L   B E N C H   M A R K S


                         BENCH MARK STAMPING:  S 147 1979
                         DESIGNATION:          S 147

MONUMENTATION:           Bench Mark disk                       VM#:         3937
AGENCY:                  US Coast & Geodetic Survey
                         (USC&GS)                                 IDB PID#:  DD0874
SETTING CLASSIFICATION:  Stainless steel rod                   OPUS PID:        
LATITUDE:   33° 14.9' N (  33.24830)          LONGITUDE:  79° 15.5' W ( -79.25830)


The bench mark is a disk set along the main dirt road, 7.32 m (24.0 ft) SE of
the bend in a 0.46 m (1.5 ft) wide drainage ditch, 7.07 m (23.2 ft) south of the
centerline of the dirt road leading the the ferry, 5.79 m (19.0 ft) west of a
secondary dirt road, and 0.61 m (2.0 ft) west of a witness post with sign.  The
bench mark is at ground level, crimped to the top of a stainless steel rod
driven 2.7 m (8.9 ft) to refusal.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  5 of  6

                                                                                
Station ID: 8662549                         PUBLICATION DATE:  02/05/2004
Name:       SOUTH ISLAND FERRY, WINYAH BAY                    
            SC
NOAA Chart: 11532                           Latitude:   33° 15.1' N (  33.25170)
USGS Quad:  GEORGETOWN SOUTH                Longitude:  79° 16.1' W ( -79.26830)


                            T I D A L   D A T U M S 


Tidal datums at SOUTH ISLAND FERRY, WINYAH BAY based on:

     LENGTH OF SERIES:      1 YEAR
     TIME PERIOD:           January 1977 - December 1977
     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 (05/31/1977)         =  1.628
     MEAN HIGHER HIGH WATER                     MHHW   =  1.256
     MEAN HIGH WATER                            MHW    =  1.168
     North American Vertical Datum              NAVD88 =  0.662
     MEAN SEA LEVEL                             MSL    =  0.613
     MEAN TIDE LEVEL                            MTL    =  0.606
     MEAN LOW WATER                             MLW    =  0.044
     MEAN LOWER LOW WATER                       MLLW   =  0.000
     LOWEST  OBSERVED WATER LEVEL (02/05/1977)         = -0.490

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     2549 A 1976                                 1.695    0.527
     BM 1 1935                                   1.959    0.791
     2549 B 1976                                 1.573    0.405
     2549 C 1976                                 1.815    0.647
     S 147 1979                                  2.541    1.373


                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  6 of  6

                                                                                
Station ID: 8662549                         PUBLICATION DATE:  02/05/2004
Name:       SOUTH ISLAND FERRY, WINYAH BAY                    
            SC
NOAA Chart: 11532                           Latitude:   33° 15.1' N (  33.25170)
USGS Quad:  GEORGETOWN SOUTH                Longitude:  79° 16.1' W ( -79.26830)


                             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.

Return to Top
Products available at 8662549 SOUTH ISLAND FERRY, WINYAH BAY, SC