Superseded Bench Mark Sheet for 8661609, OAKS CR. INLET, MURRELLS INLET SC

Present Epoch

Printable version

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  5

                                                   PUBLICATION DATE:  06/27/1989
Station ID: 8661609                                SUPERCEDED DATE:   04/21/2003
Name:       OAKS CREEK ENTRANCE, MURRELLS INLET               
            SOUTH CAROLINA
NOAA Chart: 11535                                  Latitude:         33° 31.8' N
USGS Quad:  BROOKGREEN                             Longitude:        79°  2.6' W


To reach the tidal bench marks from the surfaced ramp in the town of Murrells
Inlet, proceed by boat south on the dredged channel for about 2.7 statue miles
(4.3 km) to the entrance of Oaks Creek, continue west on Oaks Creek for 0.5 mile
(0.8 km) to the NE end of Drunken Jack Island.  The tidal bench marks are along
the NE side and end of Drunken Jack Island.  The tide gage and staff were on a
small offshore structure in the middle of the creek.


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


                 PRIMARY BENCH MARK STAMPING:  O.C.I. NO 2 1975

MONUMENTATION:           Survey Disk                               VM#:     3839
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Copper-clad Steel Rod


The bench mark is on an irregularly shaped mound on the NE end of Drunken Jack
Island, about 90 feet (27 m) south of Oaks Creek, about 90 feet (27 m) east of a
slough, and 6.9 feet (2.1 m) east of a metal witness post with sign.  The bench
mark is 2 feet (1 m) above marsh level, crimped to a copper-clad steel rod
driven 46 feet (14 m) to refusal, and encased in a 4-inch PVC pipe.



                         BENCH MARK STAMPING:  O.C.I. NO 3 1975

MONUMENTATION:           Survey Disk                               VM#:     3840
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Copper-clad Steel Rod


The bench mark is on an irregularly shaped mound on the NE end of Drunken Jack
Island, about 540 feet (165 m) SSE of Bench Mark O.C.I. NO 2 1975, 172 feet (52
m) WNW of Bench Mark O.C.I. NO 4 1975, 150 feet (46 m) south of a slough, about
120 feet (37 m) NE of the tree line, and 7.7 feet (2.3 m) SW of a metal witness
post with sign.  The bench mark is 2 feet (1 m) above marsh level, crimped to a
copper-clad steel rod driven 40 feet (12 m) to refusal, and encased in a 4-inch
PVC pipe.

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

                                                   PUBLICATION DATE:  06/27/1989
Station ID: 8661609                                SUPERCEDED DATE:   04/21/2003
Name:       OAKS CREEK ENTRANCE, MURRELLS INLET               
            SOUTH CAROLINA
NOAA Chart: 11535                                  Latitude:         33° 31.8' N
USGS Quad:  BROOKGREEN                             Longitude:        79°  2.6' W


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


                         BENCH MARK STAMPING:  O.C.I. NO 4 1975

MONUMENTATION:           Survey Disk                               VM#:     3841
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Copper-clad Steel Rod


The bench mark is on the NE side of Drunken Jack Island, about 630 feet    (192
m) south of Oaks Creek, 438 feet (134 m) ESE of Bench Mark O.C.I. NO 5 1975,
about 30 feet (9 m) east of the tree line, about 15 feet (5 m) SSW of a lone
scrub pine tree, and 11.6 feet (3.5 m) west of a metal witness post.  The bench
mark is crimped to a copper-clad steel rod driven 50 feet (15 m) to substantial
resistance, and encased in a 4-inch PVC pipe.



                         BENCH MARK STAMPING:  O.C.I. NO 5 1975

MONUMENTATION:           Survey Disk                               VM#:     3842
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Copper Pipe


The bench mark is brazed to the top of a 3.5 foot (1.1 m) long 2-inch copper
pipe in the center of a 50-foot (15 m) diameter low mound on the NE side of
Drunken Jack Island, about 300 feet (91 m) west of Bench Mark O.C.I. NO 3 1975,
about 210 feet (64 m) south of a slough, about 90 feet (27 m) north of the tree
line, 5.3 feet (1.6 m) east of a metal witness post with sign, 5.0 feet (1.5 m)
east of a lone pine tree, and 0.5 foot (0.2 m) above grade.

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

                                                   PUBLICATION DATE:  06/27/1989
Station ID: 8661609                                SUPERCEDED DATE:   04/21/2003
Name:       OAKS CREEK ENTRANCE, MURRELLS INLET               
            SOUTH CAROLINA
NOAA Chart: 11535                                  Latitude:         33° 31.8' N
USGS Quad:  BROOKGREEN                             Longitude:        79°  2.6' W


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


                         BENCH MARK STAMPING:  MSL 5.535

MONUMENTATION:           Survey Disk                               VM#:     3843
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Concrete Monument


The bench mark is set in a 10-inch tile pipe filled with concrete on the western
point of a small marsh island just NE of Drunken Jack Island, about 135 feet (41
m) east of the channel between the two islands, and about 45 feet (14 m) south
of Oaks Creek.  Note:  Use with caution, a 1982 recovery found the mark
projecting 3.5 feet (1.1 m) above grade.



                         BENCH MARK STAMPING:  NO STAMPING 1

MONUMENTATION:           Survey Disk                               VM#:     3844
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Concrete Monument


The bench mark is set in a 8-inch square terra cotta pipe filled with concrete,
476 feet (145 m) SSE of Bench Mark O.C.I. NO 2 1975, 126 feet (38 m) NW of Bench
Mark O.C.I. NO 3 1975, 3.0 feet (0.9 m) north of a metal witness post with sign,
and 1.0 foot (0.3 m) east of a COE witness post.

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

                                                   PUBLICATION DATE:  06/27/1989
Station ID: 8661609                                SUPERCEDED DATE:   04/21/2003
Name:       OAKS CREEK ENTRANCE, MURRELLS INLET               
            SOUTH CAROLINA
NOAA Chart: 11535                                  Latitude:         33° 31.8' N
USGS Quad:  BROOKGREEN                             Longitude:        79°  2.6' W


                            T I D A L   D A T U M S 


Tidal datums at OAKS CREEK ENTRANCE, MURRELLS INLET based on:

     LENGTH OF SERIES:      7 MONTHS
     TIME PERIOD:           MAY - NOVEMBER 1975
     TIDAL EPOCH:           1960-1978
     CONTROL TIDE STATION:  8661559 SMITHS DOCK


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

     HIGHEST OBSERVED WATER LEVEL (06/10/1975)         =   7.16
     MEAN HIGHER HIGH WATER                     MHHW   =   4.88
     MEAN HIGH WATER                            MHW    =   4.51
     MEAN TIDE LEVEL                            MTL    =   2.35
     MEAN LOW WATER                             MLW    =   0.20
     MEAN LOWER LOW WATER                       MLLW   =   0.00
     LOWEST  OBSERVED WATER LEVEL (11/22/1975)         =  -1.08



Bench Mark Elevation Information                In FEET above:

     Stamping or Designation                    MLLW        MHW

     O.C.I. NO 2 1975                            6.44      1.93
     O.C.I. NO 3 1975                            5.64      1.13
     O.C.I. NO 4 1975                            6.63      2.12
     O.C.I. NO 5 1975                            7.77      3.26
     MSL 5.535                                   7.24      2.73
     NO STAMPING 1                               5.04      0.53


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

                                                   PUBLICATION DATE:  06/27/1989
Station ID: 8661609                                SUPERCEDED DATE:   04/21/2003
Name:       OAKS CREEK ENTRANCE, MURRELLS INLET               
            SOUTH CAROLINA
NOAA Chart: 11535                                  Latitude:         33° 31.8' N
USGS Quad:  BROOKGREEN                             Longitude:        79°  2.6' 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.

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