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Bench Mark Sheet for 8665567, BEN SAWYER BRIDGE, IWW 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Superseded Epoch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Small blue map location marker Unpublished bench mark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  7

                                                                                
Station ID: 8665567                         PUBLICATION DATE:  05/23/2003
Name:       BEN SAWYER BRIDGE, IWW                            
            SC
NOAA Chart: 11524                           Latitude:   32° 46.4' N (  32.77330)
USGS Quad:  FORT MOULTRIE                   Longitude:  79° 50.5' W ( -79.84170)


To reach the tidal bench marks from the intersection of U.S. Highway 17 and
State Highway 703, proceed SE on State Highway 703 for 2.98 km (1.85 mi) to Ben
Sawyer Memorial Bridge; just before the bridge turn left onto a paved road
leading to the East Cooper Outboard Club property, follow the road for about 0.3
km (0.2 mi) to the Intracoastal Waterway and a dock.  The bench marks are along
State Highway 703 and along the access road.  The tide gage and staff were on
the dock about 183 m (600 ft) NE of the bridge.


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


                 PRIMARY BENCH MARK STAMPING:  5567 A 1976
                         DESIGNATION:          866 5567 A TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         4197
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  CJ0591
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   32° 46.5' N (  32.77500)          LONGITUDE:  79° 50.5' W ( -79.84170)


The primary bench mark is a disk set on the East Cooper Outboard Club property,
62 m (203 ft) NE of the NE corner of the clubhouse, 4.02 m (13.2 ft) WSW of a 1
m (3 ft) diameter pine tree, and 1.46 m (4.8 ft) SE of power pole #91562 with
two guy wires.  The bench mark is level with the ground, crimped to 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  7

                                                                                
Station ID: 8665567                         PUBLICATION DATE:  05/23/2003
Name:       BEN SAWYER BRIDGE, IWW                            
            SC
NOAA Chart: 11524                           Latitude:   32° 46.4' N (  32.77330)
USGS Quad:  FORT MOULTRIE                   Longitude:  79° 50.5' W ( -79.84170)


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


                         BENCH MARK STAMPING:  PLEASANT 1942
                         DESIGNATION:          PLEASANT

MONUMENTATION:           Triangulation Station disk            VM#:         4194
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GC)                              IDB PID#:  CJ0167
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID#: CJ0167
LATITUDE:   32° 47.2' N (  32.78670)          LONGITUDE:  79° 51.0' W ( -79.85000)


The bench mark is a disk set in the top of a concrete monument between the
highway and the marsh, 20.97 m (68.8 ft) NNW of power pole #21418 with two guy
wires and a street light, 20 m (66 ft) SSE of bench mark PLEASANT NO 1 1942,
10.03 m (32.9 ft) ENE of the centerline of the highway, 0.91 m (3.0 ft) WSW of a
wooden post, and 0.12 m (0.4 ft) above the ground.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  7

                                                                                
Station ID: 8665567                         PUBLICATION DATE:  05/23/2003
Name:       BEN SAWYER BRIDGE, IWW                            
            SC
NOAA Chart: 11524                           Latitude:   32° 46.4' N (  32.77330)
USGS Quad:  FORT MOULTRIE                   Longitude:  79° 50.5' W ( -79.84170)


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


                         BENCH MARK STAMPING:  PLEASANT NO 1 1942
                         DESIGNATION:          PLEASANT RM 1

MONUMENTATION:           Reference Mark disk                   VM#:         4195
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  CJ0168
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID#: CJ0168
LATITUDE:   32° 47.2' N (  32.78670)          LONGITUDE:  79° 51.0' W ( -79.85000)


The bench mark is a disk set in the top of a concrete monument between the
highway and the marsh, 32.46 m (106.5 ft) SSW of the south anchor for a large TV
mast, 20.42 m (67.0 ft) SSE of power pole #116233 with three guy wires, 10 m (33
ft) ENE of the centerline of the highway, 0.49 m (1.6 ft) SSW of a witness post,
and 0.06 m (0.2 ft) above the ground.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  7

                                                                                
Station ID: 8665567                         PUBLICATION DATE:  05/23/2003
Name:       BEN SAWYER BRIDGE, IWW                            
            SC
NOAA Chart: 11524                           Latitude:   32° 46.4' N (  32.77330)
USGS Quad:  FORT MOULTRIE                   Longitude:  79° 50.5' W ( -79.84170)


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


                         BENCH MARK STAMPING:  X 70 1952
                         DESIGNATION:          X 70

MONUMENTATION:           Bench Mark disk                       VM#:         4196
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  CJ0165
SETTING CLASSIFICATION:  Bridge abutment                       OPUS PID:        
LATITUDE:   32° 46.4' N (  32.77330)          LONGITUDE:  79° 50.5' W ( -79.84170)


The bench mark is a disk set in the NW abutment of Ben Sawyer Memorial Bridge, 5
m (18 ft) SW of the centerline of the highway, 1 m (2 ft) west of a concrete and
steel banister, and 0.15 m (0.5 ft) above the highway.



                         BENCH MARK STAMPING:  5567 B 1976
                         DESIGNATION:          866 5567 B TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         4198
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  CJ0590
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   32° 46.5' N (  32.77500)          LONGITUDE:  79° 50.5' W ( -79.84170)


The bench mark is a disk set at the entrance gate to the East Cooper Outboard
Club property, 51.51 m (169.0 ft) NE of the centerline of the highway, 4 m (13
ft) SE of the centerline of the driveway, 0.55 m (1.8 ft) NW of a witness post,
and 0.37 m (1.2 ft) ESE of the north corner of a concrete block pillar.  The
bench mark is level with the ground, crimped to 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  5 of  7

                                                                                
Station ID: 8665567                         PUBLICATION DATE:  05/23/2003
Name:       BEN SAWYER BRIDGE, IWW                            
            SC
NOAA Chart: 11524                           Latitude:   32° 46.4' N (  32.77330)
USGS Quad:  FORT MOULTRIE                   Longitude:  79° 50.5' W ( -79.84170)


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


                         BENCH MARK STAMPING:  5567 C 1976
                         DESIGNATION:          866 5567 C TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         4199
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  CJ0589
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   32° 46.8' N (  32.78000)          LONGITUDE:  79° 50.8' W ( -79.84670)


The bench mark is a disk set on the east side of State Highway 703, 0.72 km
(0.45 mi) NW of the NW end of Ben Sawyer Memorial Bridge, 8.44 m (27.7 ft) ENE
of the centerline of the highway, 5.91 m (19.4 ft) west of power pole #21429,
2.19 m (7.2 ft) NW of the SW anchor of a guy wire, and 0.49 m (1.6 ft) ENE of a
witness post.  The bench mark is level with the ground, crimped to 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  6 of  7

                                                                                
Station ID: 8665567                         PUBLICATION DATE:  05/23/2003
Name:       BEN SAWYER BRIDGE, IWW                            
            SC
NOAA Chart: 11524                           Latitude:   32° 46.4' N (  32.77330)
USGS Quad:  FORT MOULTRIE                   Longitude:  79° 50.5' W ( -79.84170)


                            T I D A L   D A T U M S 


Tidal datums at BEN SAWYER BRIDGE, IWW based on:

     LENGTH OF SERIES:      3 MONTHS
     TIME PERIOD:           July 1976 - September 1976
     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:

     MEAN HIGHER HIGH WATER                     MHHW   =  1.710
     MEAN HIGH WATER                            MHW    =  1.596
     North American Vertical Datum              NAVD88 =  0.963
     MEAN SEA LEVEL                             MSL    =  0.853
     MEAN TIDE LEVEL                            MTL    =  0.826
     MEAN LOW WATER                             MLW    =  0.057
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     5567 A 1976                                 2.434    0.838
     PLEASANT 1942                               2.573    0.977
     PLEASANT NO 1 1942                          2.613    1.017
     X 70 1952                                   9.018    7.422
     5567 B 1976                                 2.359    0.763
     5567 C 1976                                 2.814    1.218


                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  7 of  7

                                                                                
Station ID: 8665567                         PUBLICATION DATE:  05/23/2003
Name:       BEN SAWYER BRIDGE, IWW                            
            SC
NOAA Chart: 11524                           Latitude:   32° 46.4' N (  32.77330)
USGS Quad:  FORT MOULTRIE                   Longitude:  79° 50.5' W ( -79.84170)


                             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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Products available at 8665567 BEN SAWYER BRIDGE, IWW, SC

Revised: 08/08/2018
NOAA / National Ocean Service
Web site owner: Center for Operational Oceanographic Products and Services