Bench Mark Sheet for 8666217, YONGES ISLAND, WADMALAW 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Superseded Epoch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Small blue map location marker Unpublished bench mark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: 8666217                         PUBLICATION DATE:  08/11/2003
Name:       YOUNGES ISLAND, WADMALAW RIVER                    
            SC
NOAA Chart: 11522                           Latitude:   32° 41.7' N (  32.69500)
USGS Quad:  WADMALAW RIVER                  Longitude:  80° 13.4' W ( -80.22330)


To reach the tidal bench marks from the intersection of U.S. Highway 17 and S.C.
162, proceed south on S.C. 162 11.4 km (7.1 mi) to S.C. 165 in Hollywood S.C.,
south onto S.C. 165 5.3 km (3.3 mi) to Meggett, South Carolina, left at sign
Simmons Bluff 0.6 km (0.4 mi) to Pederson residence.  The bench marks are
located west of the Pederson residence and in the vicinity of the Younges Island
Post Office.  The gage and staff were located on a private dock behind the
residence.


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


                 PRIMARY BENCH MARK STAMPING:  6217 F 1977
                         DESIGNATION:          866 6217 F TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         4288
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  CK2458
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   32° 41.8' N (  32.69670)          LONGITUDE:  80° 13.5' W ( -80.22500)


The primary bench mark is a disk located at the SW corner of the garage of
Pederson residence, 27.13 m (89.0 ft) NE of power pole No. 144010, 14.33 m (47.0
ft) east of the Y in the dirt driveway, 12.56 m (41.2 ft) SSW of the centerline
of brick wall leading to front door of residence, 4.57 m (15.0 ft) west of the
electric meter box on side of house, and 1.19 m (3.9 ft) WSW of the SW corner of
the garage.  The bench Mark is crimped to the top of a copper-clad steel rod
driven 10 m (32 ft) to refusal, encased in 4-inch PVC pipe and concrete
kickblock.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  5

                                                                                
Station ID: 8666217                         PUBLICATION DATE:  08/11/2003
Name:       YOUNGES ISLAND, WADMALAW RIVER                    
            SC
NOAA Chart: 11522                           Latitude:   32° 41.7' N (  32.69500)
USGS Quad:  WADMALAW RIVER                  Longitude:  80° 13.4' W ( -80.22330)


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


                         BENCH MARK STAMPING:  NO 1
                         DESIGNATION:          866 6217 TIDAL 1

MONUMENTATION:           Tidal Station disk                    VM#:         4283
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:        
SETTING CLASSIFICATION:  Remains of old water tower            OPUS PID:        
LATITUDE:   32° 41.7' N (  32.69500)          LONGITUDE:  80° 13.4' W ( -80.22330)


The bench mark is a disk set flush in the top of remains of an old water tower,
south of the Younges Island Post Office, 21.00 m (68.9 ft) NNE of power pole No.
54185, 11.89 m (39.0 ft) east of the centerline of a dirt driveway, 0.46 m (1.5
ft) NNW of a cinder block wall, and 0.3 m (1.0 ft) above ground level.



                         BENCH MARK STAMPING:  NO 2
                         DESIGNATION:          866 6217 TIDAL 2

MONUMENTATION:           Tidal Station disk                    VM#:         4284
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:        
SETTING CLASSIFICATION:  Window sill                           OPUS PID:        
LATITUDE:   32° 41.7' N (  32.69500)          LONGITUDE:  80° 13.4' W ( -80.22330)


The bench mark is a disk set flush in the left side window sill of Yonges Island
Post Office, 5.00 m (16.4 ft) NW of flag pole, 3.20 m (10.5 ft) east of the west
corner of the post office, and 2.44 m (8.0 ft) west of the centerline of the
front door of the post office.

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

                                                                                
Station ID: 8666217                         PUBLICATION DATE:  08/11/2003
Name:       YOUNGES ISLAND, WADMALAW RIVER                    
            SC
NOAA Chart: 11522                           Latitude:   32° 41.7' N (  32.69500)
USGS Quad:  WADMALAW RIVER                  Longitude:  80° 13.4' W ( -80.22330)


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


                         BENCH MARK STAMPING:  6217 G 1977
                         DESIGNATION:          866 6217 G TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         4289
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  CK2454
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID#: CK2454
LATITUDE:   32° 41.7' N (  32.69500)          LONGITUDE:  80° 13.5' W ( -80.22500)


The bench mark is a disk located near the bend in the paved road by power pole
No. 77849, 12.80 m (42.0 ft) SW of brick driveway marker, 4.94 m (16.2 ft) SE of
power pole No. 77849, 4.27 m (14.0 ft) west of centerline of paved road, and
0.91 m (3.0 ft) west of the west side of paved road.  The bench mark is crimped
to the top of a copper-clad steel rod driven 10 m (32 ft) to refusal, encased in
4-inch PVC and concrete kickblock.

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

                                                                                
Station ID: 8666217                         PUBLICATION DATE:  08/11/2003
Name:       YOUNGES ISLAND, WADMALAW RIVER                    
            SC
NOAA Chart: 11522                           Latitude:   32° 41.7' N (  32.69500)
USGS Quad:  WADMALAW RIVER                  Longitude:  80° 13.4' W ( -80.22330)


                            T I D A L   D A T U M S 


Tidal datums at YOUNGES ISLAND, WADMALAW RIVER based on:

     LENGTH OF SERIES:      1 YEAR
     TIME PERIOD:           May 1977 - April 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)         =  2.670
     MEAN HIGHER HIGH WATER                     MHHW   =  2.155
     MEAN HIGH WATER                            MHW    =  2.046
     North American Vertical Datum              NAVD88 =  1.238
     MEAN SEA LEVEL                             MSL    =  1.226
     MEAN TIDE LEVEL                            MTL    =  1.056
     MEAN LOW WATER                             MLW    =  0.067
     MEAN LOWER LOW WATER                       MLLW   =  0.000
     LOWEST  OBSERVED WATER LEVEL (01/09/1978)         = -0.945

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     6217 F 1977                                 5.855    3.809
     NO 1                                        3.986    1.940
     NO 2                                        5.339    3.293
     6217 G 1977                                 5.102    3.056


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

                                                                                
Station ID: 8666217                         PUBLICATION DATE:  08/11/2003
Name:       YOUNGES ISLAND, WADMALAW RIVER                    
            SC
NOAA Chart: 11522                           Latitude:   32° 41.7' N (  32.69500)
USGS Quad:  WADMALAW RIVER                  Longitude:  80° 13.4' W ( -80.22330)


                             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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