Bench Mark Sheet for 8666652, FOLLY RIVER BRIDGE, FOLLY RIVER 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Superseded Epoch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Small blue map location marker Unpublished bench mark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  5

                                                                                
Station ID: 8666652                         PUBLICATION DATE:  02/05/2004
Name:       FOLLY RIVER, SOUTH                                
            SC
NOAA Chart: 11522                           Latitude:   32° 39.7' N (  32.66170)
USGS Quad:  JAMES ISLAND                    Longitude:  79° 56.7' W ( -79.94500)


To reach the tidal bench marks from the junction of State Highway 700 and State
Highway 171 (Folly Road) in James Island, proceed south on State Highway 171 for
12.31 km (7.65 mi) to the bridge over Folly River.  The bench marks are located
on the bridge and along State Highway 171.  The tide gage and staff were located
just west of the bridge on a wooden pier.


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


                 PRIMARY BENCH MARK STAMPING:  6652 B 1976
                         DESIGNATION:          866 6652 B TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         4330
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  CJ0441
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   32° 39.8' N (  32.66330)          LONGITUDE:  79° 56.6' W ( -79.94330)


The primary bench mark is a disk located on the east side of State Highway 171,
83.61 m (274.3 ft) north of the NE corner of the bridge, 9 m (30 ft) ENE of the
centerline of the highway, 5.79 m (19.0 ft) WSW of utility pole #33952 with a
trans- former and 7 guy wires, and 0.58 m (1.9 ft) ENE of a metal witness post. 
The bench mark is set 1 m (3 ft) below the highway, crimped to the top of a
copper-clad steel rod driven 10.7 m (35 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  5

                                                                                
Station ID: 8666652                         PUBLICATION DATE:  02/05/2004
Name:       FOLLY RIVER, SOUTH                                
            SC
NOAA Chart: 11522                           Latitude:   32° 39.7' N (  32.66170)
USGS Quad:  JAMES ISLAND                    Longitude:  79° 56.7' W ( -79.94500)


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


                         BENCH MARK STAMPING:  C-6 1974
                         DESIGNATION:          C-6

MONUMENTATION:           Survey disk                           VM#:         4329
AGENCY:                  Local Surveyor (LOCSUR)               IDB PID#:  CJ0443
SETTING CLASSIFICATION:  Concrete abutment                     OPUS PID:        
LATITUDE:   32° 39.8' N (  32.66330)          LONGITUDE:  79° 56.6' W ( -79.94330)


The bench mark is a disk set flush in the NE concrete abutment of the State
Highway 171 bridge over Folly River, 6.83 m (22.4 ft) east of the centerline of
State Highway 171, 1.13 m (3.7 ft) east of the east railing on the bridge, 0.21
m (0.7 ft) west of the east edge of the bridge abutment, and 0.3 m (1 ft) above
the highway.



                         BENCH MARK STAMPING:  6652 D 1976
                         DESIGNATION:          866 6652 D TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         4331
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  CJ0439
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   32° 39.8' N (  32.66330)          LONGITUDE:  79° 56.7' W ( -79.94500)


The bench mark is a disk located on the west side of State Highway 171, 11.28 m
(37.0 ft) WSW of the centerline of the highway, 8.47 m (27.8 ft) west of the
east post of the Folly Beach City Limits sign, 1.83 m (6.0 ft) NNW of utility
pole #A6434, and 0.61 m (2.0 ft) west of a metal witness post.  The bench mark
is crimped to the top of a copper-clad steel rod driven 9.8 m (32 ft) to
refusal, and encased in a 5-inch PVC pipe and concrete kickblock.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  5

                                                                                
Station ID: 8666652                         PUBLICATION DATE:  02/05/2004
Name:       FOLLY RIVER, SOUTH                                
            SC
NOAA Chart: 11522                           Latitude:   32° 39.7' N (  32.66170)
USGS Quad:  JAMES ISLAND                    Longitude:  79° 56.7' W ( -79.94500)


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


                         BENCH MARK STAMPING:  6652 E 1983
                         DESIGNATION:          866 6652 E TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         4332
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  CJ0442
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   32° 39.8' N (  32.66330)          LONGITUDE:  79° 56.6' W ( -79.94330)


The bench mark is a disk set in the top of a concrete monument on the west side
of State highway 171, in the median between the entrances to Mariners Cay and
Bushys Seafood Restaurant, 34.38 m (112.8 ft) WNW of Bench Mark 6652 B 1976,
32.10 m (105.3 ft) SSE of the center of the entrance doors to the restaurant,
18.56 m (60.9 ft) WSW of the centerline of the highway, 8.41 m (27.6 ft) NNW of
the centerline of the north entrance road to Mariners Cay, 3.20 m (10.5 ft) SSE
of a fire hydrant, and level with the ground.  NOTE: A thorough search revealed
no evidence of the mark in 1990.



                         BENCH MARK STAMPING:  6652 F 1983
                         DESIGNATION:          866 6652 F TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         4333
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  CJ0440
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   32° 39.8' N (  32.66330)          LONGITUDE:  79° 56.6' W ( -79.94330)


The bench mark is a disk set in the top of a concrete monument on the east side
of State Highway 171, near the marsh, 58.49 m (191.9 ft) NNW of Bench Mark 6652
B 1976, 10.24 m (33.6 ft) NW of the anchor line to a utility pole, 9.42 m (30.9
ft) ENE of the centerline of the highway, 8.17 m (26.8 ft) west of a utility
pole, 0.61 m (2.0 ft) west of a metal witness post, and 1 m (3 ft) below the
highway.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  5

                                                                                
Station ID: 8666652                         PUBLICATION DATE:  02/05/2004
Name:       FOLLY RIVER, SOUTH                                
            SC
NOAA Chart: 11522                           Latitude:   32° 39.7' N (  32.66170)
USGS Quad:  JAMES ISLAND                    Longitude:  79° 56.7' W ( -79.94500)


                            T I D A L   D A T U M S 


Tidal datums at FOLLY RIVER, SOUTH 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)         =  2.351
     MEAN HIGHER HIGH WATER                     MHHW   =  1.778
     MEAN HIGH WATER                            MHW    =  1.662
     North American Vertical Datum              NAVD88 =  0.986
     MEAN SEA LEVEL                             MSL    =  0.901
     MEAN TIDE LEVEL                            MTL    =  0.859
     MEAN LOW WATER                             MLW    =  0.056
     MEAN LOWER LOW WATER                       MLLW   =  0.000
     LOWEST  OBSERVED WATER LEVEL (11/22/1976)         = -0.515

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     6652 B 1976                                 2.482    0.820
     C-6 1974                                    4.000    2.338
     6652 D 1976                                 2.698    1.036
     6652 E 1983                                 3.147    1.485
     6652 F 1983                                 2.121    0.459


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

                                                                                
Station ID: 8666652                         PUBLICATION DATE:  02/05/2004
Name:       FOLLY RIVER, SOUTH                                
            SC
NOAA Chart: 11522                           Latitude:   32° 39.7' N (  32.66170)
USGS Quad:  JAMES ISLAND                    Longitude:  79° 56.7' W ( -79.94500)


                             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.

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