Superseded Bench Mark Sheet for 8664531, BACON BRIDGE, ASHLEY RIVER SC

Present Epoch

Printable version

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  4

                                                   PUBLICATION DATE:  03/22/1984
Station ID: 8664531                                SUPERCEDED DATE:   04/21/2003
Name:       BACON BRIDGE, ASHLEY RIVER                        
            SOUTH CAROLINA
NOAA Chart: 11521                                  Latitude:         32° 57.5' N
USGS Quad:  STALLSVILLE                            Longitude:        80° 12.2' W


To reach the tidal bench marks from the intersection of S.C. Highway 7 and S.C.
Highway 61 proceed north on S.C. Highway 61 15.2 miles (24.5 km) to Y
intersection of S.C. Highway 61 and S.C. Highway 165, bear right onto S.C.
Highway 165 for 1.0 miles (1.6 km) Bacon Bridge is the second bridge past the
junction of S.C. Highways 165 and 61.  The bench marks are located north and
west of the bridge, and the gage and staff were located on the west side of the
bridge.


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


                 PRIMARY BENCH MARK STAMPING:  4531 A 1976

MONUMENTATION:           Survey Disk                               VM#:     4044
AGENCY:                                                            PID#:  CK3053
SETTING CLASSIFICATION:  Copper-Clad Steel Rod


The bench mark is in a clearing west of the bridge 61.5 feet (18.7 m) west of SW
bridge abutment, 45.5 feet (13.9 m) west of 3.0 feet (0.9 m) diameter oak tree,
and 11.5 feet (3.5 m) NNW of 3.0 feet (0.9 m) diameter dead oak tree.  The bench
mark is at ground level, crimped to the top of a copper-clad steel rod driven 12
feet (4 m) to refusal, encased in a 4-inch PVC pipe and concrete kickblock.



                         BENCH MARK STAMPING:  4531 C 1976

MONUMENTATION:           Survey Disk                               VM#:     4045
AGENCY:                                                            PID#:  CK3052
SETTING CLASSIFICATION:  Concrete Abutment


The bench mark is located in NE bridge abutment, 213 feet (65 m) south of Bench
Mark 4531 D 1976, 24.7 feet (7.5 m) east of centerline of S.C. Highway 165, and
13.9 feet (4.2 m) SW of power pole #37687.  The bench mark is 0.8 feet (0.2 m)
above ground level, set flush in bridge abutment.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  4

                                                   PUBLICATION DATE:  03/22/1984
Station ID: 8664531                                SUPERCEDED DATE:   04/21/2003
Name:       BACON BRIDGE, ASHLEY RIVER                        
            SOUTH CAROLINA
NOAA Chart: 11521                                  Latitude:         32° 57.5' N
USGS Quad:  STALLSVILLE                            Longitude:        80° 12.2' W


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


                         BENCH MARK STAMPING:  4531 D 1976

MONUMENTATION:           Survey Disk                               VM#:     4046
AGENCY:                                                            PID#:  CK3051
SETTING CLASSIFICATION:  Copper-Clad Steel Rod


The bench mark is north of the bridge on S.C. Highway 165, 33.7 feet (10.3 m)
east of centerline of S.C. Highway 165, and 4.3 feet (1.3 m) west of power pole
#92920.  The bench mark is 0.1 foot (0.1 m) above ground level, crimped to the
top of a copper-clad steel rod driven 14 feet (4 m) to refusal, encased in a
4-inch PVC pipe and concrete kickblock.



                         BENCH MARK STAMPING:  4531 E 1976

MONUMENTATION:           Survey Disk                               VM#:     4047
AGENCY:                                                            PID#:  CK3050
SETTING CLASSIFICATION:  Copper-Clad Steel Rod


The bench mark is on the west side of S.C. Highway 165, north of the bridge 82.0
feet (25.0 m) east of NE corner of concrete block house, 26.7 feet (8.1 m) north
of paved driveway leading to house, 23.6 feet (7.2 m) NE of centerline of S.C.
Highway 165, and 13.0 feet (4.0 m) SE of power pole #8002.  The bench mark at
ground level, crimped to the top of a copper-clad steel rod driven 21 feet (6 m)
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  4

                                                   PUBLICATION DATE:  03/22/1984
Station ID: 8664531                                SUPERCEDED DATE:   04/21/2003
Name:       BACON BRIDGE, ASHLEY RIVER                        
            SOUTH CAROLINA
NOAA Chart: 11521                                  Latitude:         32° 57.5' N
USGS Quad:  STALLSVILLE                            Longitude:        80° 12.2' W


                            T I D A L   D A T U M S 


Tidal datums at BACON BRIDGE, ASHLEY RIVER based on:

     LENGTH OF SERIES:      4 MONTHS
     TIME PERIOD:           JUL & DEC 1976, FEB & MAR 1977 
     TIDAL EPOCH:           1960-1978
     CONTROL TIDE STATION:  8665530 CHARLESTON


Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET:

     HIGHEST OBSERVED WATER LEVEL (12/19/1976)         =   4.79
     MEAN HIGHER HIGH WATER                     MHHW   =   2.22
     MEAN HIGH WATER                            MHW    =   2.01
     MEAN TIDE LEVEL                            MTL    =   1.04
     MEAN LOW WATER                             MLW    =   0.07
     MEAN LOWER LOW WATER                       MLLW   =   0.00
     LOWEST  OBSERVED WATER LEVEL (07/31/1976)         =  -3.24

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In FEET above:

     Stamping or Designation                    MLLW        MHW

     4531 A 1976                                 6.86      4.85
     4531 C 1976                                15.35     13.34
     4531 D 1976                                15.00     12.99
     4531 E 1976                                21.34     19.33


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

                                                   PUBLICATION DATE:  03/22/1984
Station ID: 8664531                                SUPERCEDED DATE:   04/21/2003
Name:       BACON BRIDGE, ASHLEY RIVER                        
            SOUTH CAROLINA
NOAA Chart: 11521                                  Latitude:         32° 57.5' N
USGS Quad:  STALLSVILLE                            Longitude:        80° 12.2' W


                             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 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 8664531 BACON BRIDGE, ASHLEY RIVER, SC