U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
PUBLICATION DATE: 08/30/1988
Station ID: 8660265 SUPERCEDED DATE: 04/21/2003
Name: CHERRY GROVE, INSIDE OF CLOSED CHERRY GROVE INLET
SOUTH CAROLINA
NOAA Chart: 11535 Latitude: 33° 50.1' N
USGS Quad: WAMPEE Longitude: 78° 38.0' W
To reach the tidal bench marks from the State Route 65 overpass over U.S.
Highway 17, proceed south on State Route 65 for 1.5 miles (2.4 km) to Ocean
Boulevard, then turn left and go east on Ocean Boulevard to 39th Avenue North,
then north on 39th Avenue North for 0.2 mile (0.3 km) 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 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
MONUMENTATION: Survey Disk VM#: 3692
AGENCY: PID#: DD1709
SETTING CLASSIFICATION: Copper-clad Steel Rod
The bench mark is NW of the intersection of 39th Avenue North and 38th Avenue
North, 27.4 feet (8.4 m) NW of a large bush, 10 feet (3 m) south of the
approximate water's edge, and 2.3 feet (0.7 m) west of a witness post. The
bench mark is 0.2 foot (0.1 m) above ground level, crimped to a copper-clad
steel rod driven to an unspecified depth, and encased in a PVC pipe and square
concrete kickblock.
BENCH MARK STAMPING: CHER NO 3 1974
MONUMENTATION: Survey Disk VM#: 3693
AGENCY: PID#: DD1708
SETTING CLASSIFICATION: Copper-clad Steel Rod
The bench mark is on a rise SE of Bench Mark CHER NO 1 1974, 132.0 feet (40.2 m)
NE of the NE corner of a grey house (measured from pillar), 22.7 feet (6.9 m)
east of the centerline of 38th Avenue North, 6.0 feet (1.8 m) SW of the
approximate high water line, and 1.4 feet (0.4 m) NW of a witness sign. 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.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
PUBLICATION DATE: 08/30/1988
Station ID: 8660265 SUPERCEDED DATE: 04/21/2003
Name: CHERRY GROVE, INSIDE OF CLOSED CHERRY GROVE INLET
SOUTH CAROLINA
NOAA Chart: 11535 Latitude: 33° 50.1' N
USGS Quad: WAMPEE Longitude: 78° 38.0' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: CHER NO 4 1974
MONUMENTATION: Survey Disk VM#: 3694
AGENCY: PID#: DD1707
SETTING CLASSIFICATION: Copper-clad Steel Rod
The bench mark is 166.0 feet (50.6 m) south of Bench Mark CHER NO 3 1974, 27.4
feet (8.4 m) SE of a light pole, 14.7 feet (4.5 m) east of the centerline of
38th Avenue North, and 2.2 feet (0.7 m) NW of a witness post with sign. The
bench mark is at ground level, crimped to a copper-clad steel rod driven to an
unspecified depth, and encased in a PVC pipe and concrete kickblock.
BENCH MARK STAMPING: CHER NO 5 1974
MONUMENTATION: Survey Disk VM#: 3695
AGENCY: PID:
SETTING CLASSIFICATION: Copper-clad Steel Rod
The bench mark is 74.5 feet (22.7 m) SSE of Bench Mark CHER NO 4 1974, 33.3 feet
(10.1 m) NE of power pole #GPE1, and 18.8 feet (5.7 m) 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.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
PUBLICATION DATE: 08/30/1988
Station ID: 8660265 SUPERCEDED DATE: 04/21/2003
Name: CHERRY GROVE, INSIDE OF CLOSED CHERRY GROVE INLET
SOUTH CAROLINA
NOAA Chart: 11535 Latitude: 33° 50.1' N
USGS Quad: WAMPEE Longitude: 78° 38.0' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 0265 A 1976
MONUMENTATION: Survey Disk VM#: 3696
AGENCY: PID#: DD1706
SETTING CLASSIFICATION: Copper-clad Steel Rod
The bench mark is 215.5 feet (65.7 m) south of Bench Mark CHER NO 4 1974, 59.9
feet (18.3 m) NNW of the NW corner of the porch of the house on the SE corner of
38th Avenue North and Duffy Street, 29.0 feet (8.8 m) east of the centerline of
38th Avenue North, 26.0 feet (7.9 m) north of the centerline of Duffy Street,
3.9 feet (1.2 m) NNE of power pole #GP 15, and 2.3 feet (0.7 m) SE of a metal
witness post and sign. The bench mark is at ground level, crimped to a
copper-clad steel rod driven 48 feet (15 m) to refusal, and encased in a 4-inch
PVC pipe and concrete kickblock.
BENCH MARK STAMPING: 0265 B 1976
MONUMENTATION: Survey Disk VM#: 3697
AGENCY: PID#: DD1710
SETTING CLASSIFICATION: Copper-clad Steel Rod
The bench mark is near the intersection of Lake Street and 39th Avenue North,
59.4 feet (18.1 m) ESE of the SE corner of the 2-story house #3807, 31.5 feet
(9.6 m) SW of the centerline of 39th Avenue North, 24.0 feet (7.3 m) north of
the centerline of Lake Street, and 4.7 feet (1.4 m) SW of power and light pole
#G1Z1. The bench mark is 0.1 foot (0.03 m) above ground level, crimped to a
copper-clad steel rod driven 24 feet (7 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 4 of 5
PUBLICATION DATE: 08/30/1988
Station ID: 8660265 SUPERCEDED DATE: 04/21/2003
Name: CHERRY GROVE, INSIDE OF CLOSED CHERRY GROVE INLET
SOUTH CAROLINA
NOAA Chart: 11535 Latitude: 33° 50.1' N
USGS Quad: WAMPEE Longitude: 78° 38.0' W
T I D A L D A T U M S
Tidal datums at CHERRY GROVE, INSIDE OF CLOSED CHERRY GROVE INLET based on:
LENGTH OF SERIES: 1 YEAR
TIME PERIOD: JANUARY-DECEMBER 1975
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 (11/12/1974) = 7.33
MEAN HIGHER HIGH WATER MHHW = 5.24
MEAN HIGH WATER MHW = 4.86
MEAN TIDE LEVEL MTL = 2.51
MEAN LOW WATER MLW = 0.15
MEAN LOWER LOW WATER MLLW = 0.00
LOWEST OBSERVED WATER LEVEL (03/09/1975) = -0.24
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In FEET above:
Stamping or Designation MLLW MHW
CHER NO 1 1974 7.26 2.40
CHER NO 3 1974 7.69 2.83
CHER NO 4 1974 7.58 2.72
CHER NO 5 1974 7.64 2.78
0265 A 1976 7.92 3.06
0265 B 1976 10.10 5.24
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
PUBLICATION DATE: 08/30/1988
Station ID: 8660265 SUPERCEDED DATE: 04/21/2003
Name: CHERRY GROVE, INSIDE OF CLOSED CHERRY GROVE INLET
SOUTH CAROLINA
NOAA Chart: 11535 Latitude: 33° 50.1' N
USGS Quad: WAMPEE Longitude: 78° 38.0' 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.