Bench Mark Sheet for 8660265, CHERRY GROVE, INSIDE 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Superseded Epoch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Small blue map location marker Unpublished bench mark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  6

                                                                                
Station ID: 8660265                         PUBLICATION DATE:  02/05/2004
Name:       CHERRY GROVE, INSIDE                              
            SC
NOAA Chart: 11535                           Latitude:   33° 50.1' N (  33.83500)
USGS Quad:  WAMPEE                          Longitude:  78° 38.0' W ( -78.63330)


To reach the tidal bench marks from the Sea Mountain Highway overpass over U.S.
Highway 17, proceed south on Sea Mountain Highway for 3.4 km (2.1 mi) to Ocean
Boulevard, then turn left and proceed NE on Ocean Boulevard for 2.0 km (1.2 mi)
to 39th Avenue North, then turn left and proceed NW on 39th Avenue North for 0.3
km (0.2 mi) to its end at 38th Avenue North.  The bench marks are in the
vicinity of 38th and 39th Avenues North.  The tide gage and staff were located
on a small pier at the north end of a sand ridge NE of 38th Avenue North.


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


                 PRIMARY BENCH MARK STAMPING:  CHER NO 1 1974
                         DESIGNATION:          866 0265 TIDAL CHER 1

MONUMENTATION:           Tidal Station disk                    VM#:         3692
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  DD1709
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   33° 50.2' N (  33.83670)          LONGITUDE:  78° 38.0' W ( -78.63330)


The bench mark is a disk located in North Myrtle Beach at 417 36th Avenue North,
27.49 m (90.2 ft) NNE of the NE corner of a house at 417 36th Avenue North, 9.91
(32.5 ft) NW of a utility pole #72458, 4.51 m (14.8 ft) WSW of the extended
centerline of the Avenue, and 0.40 m (1.3 ft) SW of a witness post.  The bench
mark is set at ground level, crimped to a copper-clad steel rod driven to an
unspecified depth, and encased in a PVC pipe and square concrete kickblock.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  6

                                                                                
Station ID: 8660265                         PUBLICATION DATE:  02/05/2004
Name:       CHERRY GROVE, INSIDE                              
            SC
NOAA Chart: 11535                           Latitude:   33° 50.1' N (  33.83500)
USGS Quad:  WAMPEE                          Longitude:  78° 38.0' W ( -78.63330)


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


                         BENCH MARK STAMPING:  CHER NO 3 1974
                         DESIGNATION:          866 0265  TIDAL CHER 3

MONUMENTATION:           Tidal Station disk                    VM#:         3693
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  DD1708
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   33° 50.2' N (  33.83670)          LONGITUDE:  78° 38.0' W ( -78.63330)


The bench mark is disk located near 417 36th Avenue North, 20.39 m (66.9 ft) ENE
of the NE corner of a house at 417 36th Avenue North, 7.01 m (23.0 ft) east of
the centerline of 38th Avenue North, 2.01 m (6.6 ft) east of a witness ost, 0.49
m (1.6 ft) NNW of a witness post. The bench mark is set 7 cm (0.2 ft) above the
ground, crimped to a copper-clad steel rod driven 17.1 m (56 ft), and encased in
a 4-inch PVC pipe and concrete kickblock.



                         BENCH MARK STAMPING:  CHER NO 4 1974
                         DESIGNATION:          866 0265 TIDAL CHER 4

MONUMENTATION:           Tidal Station disk                    VM#:         3694
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  DD1707
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   33° 50.2' N (  33.83670)          LONGITUDE:  78° 38.0' W ( -78.63330)


The bench mark is a disk located at 411 36th Avenue North, 99.21 m (325.5 ft)
NNW of the centerline of Duffy Street, 28.71 m (94.2 ft) north of utility pole
#37649 GPE1 with a transformer and two guy cables, 14.51 m (47.6 ft) ENE of the
NE corner of a house at 411 36th Avenue North, 8.29 m (27.2 ft) ESE of utility
light pole #37648 with three guy cables, 4.60 m (15.1 ft) ENE of the centerline
of 38th Avenue North, and 0.30 m (1.0 ft) SSW of a witness post.  The bench mark
is at ground level, crimped to a copper-clad steel rod driven 17.1 m (56 ft),
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  6

                                                                                
Station ID: 8660265                         PUBLICATION DATE:  02/05/2004
Name:       CHERRY GROVE, INSIDE                              
            SC
NOAA Chart: 11535                           Latitude:   33° 50.1' N (  33.83500)
USGS Quad:  WAMPEE                          Longitude:  78° 38.0' W ( -78.63330)


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


                         BENCH MARK STAMPING:  CHER NO 5 1974
                         DESIGNATION:          866 0265 TIDAL CHER  5

MONUMENTATION:           Tidal Station disk                    VM#:         3695
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   33° 50.1' N (  33.83500)          LONGITUDE:  78° 38.0' W ( -78.63330)


The bench mark is located near the intersection of 38th and 39th Avenue North,
22.71 m (74.5 ft) SSE of bench mark CHER NO 4 1974, 10.15 m (33.3 ft) NE of
power pole #GPE1, and 5.73 m (18.8 ft) NE of the centerline of 38th Avenue
North.  The bench mark is crimped to a copper-clad steel rod driven to an
unspecified depth, and encased in a PVC pipe and concrete kickblock.  NOTE: The
bench mark was not recovered in 1992.



                         BENCH MARK STAMPING:  0265 A 1976
                         DESIGNATION:          866 0265 A TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         3696
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  DD1706
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   33° 50.1' N (  33.83500)          LONGITUDE:  78° 38.0' W ( -78.63330)


The bench mark is a disk located near the intersection of Duffy Street and 38th
Avenue North, 7.89 m (25.9 ft) NNW of the centerline of Duffy Street, 6.31 m
(20.7 ft) ENE of the centerline of 38th Avenue North, 1.40 m (4.6 ft) NNE of
utility pole #37651 GPI, 0.91 m (3.0 ft) north of utility pole #18614, and south
of a witness post.  The bench mark is set 10 cm (0.3 ft) below ground level,
crimped to a copper-clad steel rod driven 14.6 m (48 ft) to refusal, and encased
in a 4-inch PVC pipe and concrete kickblock.  NOTE: The mark was not found in
1999

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  6

                                                                                
Station ID: 8660265                         PUBLICATION DATE:  02/05/2004
Name:       CHERRY GROVE, INSIDE                              
            SC
NOAA Chart: 11535                           Latitude:   33° 50.1' N (  33.83500)
USGS Quad:  WAMPEE                          Longitude:  78° 38.0' W ( -78.63330)


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


                         BENCH MARK STAMPING:  0265 B 1976
                         DESIGNATION:          866 0265 B TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         3697
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  DD1710
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID#: DD1710
LATITUDE:   33° 50.0' N (  33.83330)          LONGITUDE:  78° 37.8' W ( -78.63000)


The bench mark is near the intersection of Lake Drive and 36th Avenue North,
9.51 m (31.2 ft) WSW of the centerline of 36th Avenue North, 8.41 m (27.6 ft) SE
of the SE corner of the house at 3809 Lake Drive, 4.69 m (15.4 ft) SW of a
witness post, and 1.80 m (5.9 ft) SW of utility pole #37721 C121 with 5 guy
cables.  The bench mark is set at ground level, crimped to a copper-clad steel
rod driven 7.3 m (24 ft) 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  5 of  6

                                                                                
Station ID: 8660265                         PUBLICATION DATE:  02/05/2004
Name:       CHERRY GROVE, INSIDE                              
            SC
NOAA Chart: 11535                           Latitude:   33° 50.1' N (  33.83500)
USGS Quad:  WAMPEE                          Longitude:  78° 38.0' W ( -78.63330)


                            T I D A L   D A T U M S 


Tidal datums at CHERRY GROVE, INSIDE based on:

     LENGTH OF SERIES:      1 YEAR
     TIME PERIOD:           January 1975 - December 1975
     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 (06/10/1975)         =  2.147
     MEAN HIGHER HIGH WATER                     MHHW   =  1.586
     MEAN HIGH WATER                            MHW    =  1.465
     North American Vertical Datum              NAVD88 =  0.859
     MEAN SEA LEVEL                             MSL    =  0.763
     MEAN TIDE LEVEL                            MTL    =  0.753
     MEAN LOW WATER                             MLW    =  0.041
     MEAN LOWER LOW WATER                       MLLW   =  0.000
     LOWEST  OBSERVED WATER LEVEL (03/09/1975)         = -0.158

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     CHER NO 1 1974                              2.129    0.664
     CHER NO 3 1974                              2.260    0.795
     CHER NO 4 1974                              2.227    0.762
     CHER NO 5 1974                              2.243    0.778
     0265 A 1976                                 2.329    0.864
     0265 B 1976                                 2.996    1.531


                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  6 of  6

                                                                                
Station ID: 8660265                         PUBLICATION DATE:  02/05/2004
Name:       CHERRY GROVE, INSIDE                              
            SC
NOAA Chart: 11535                           Latitude:   33° 50.1' N (  33.83500)
USGS Quad:  WAMPEE                          Longitude:  78° 38.0' W ( -78.63330)


                             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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