U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 6
Station ID: 8665387 PUBLICATION DATE: 02/05/2004
Name: HAMLIN CREEK, ISLE OF PALMS
SC
NOAA Chart: 11523 Latitude: 32° 47.2' N ( 32.78670)
USGS Quad: FORT MOULTRIE Longitude: 79° 47.5' W ( -79.79170)
To reach the tidal bench marks from State Highway 703 and the Thompson Memorial
Bridge over Breach Inlet in Isle of Palms, proceed NE on State Highway 703 (Palm
Boulevard) for 2.4 km (1.5 mi) to 11th Avenue, turn left onto 11th Avenue and
proceed its the end at Hamlin Creek. The bench marks are along 11th Avenue,
Palm Boulevard, and at the intersection of Carolina Boulevard and 9th Avenue.
The tide gage and staff were on a private dock behind the residence at 1101 Oak
Harbor Boulevard.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: HC NO 2 1975
DESIGNATION: 866 5387 TIDAL HC 2
MONUMENTATION: Tidal Station disk VM#: 4159
AGENCY: National Ocean Survey (NOS) IDB PID#: CJ0612
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID:
LATITUDE: 32° 47.3' N ( 32.78830) LONGITUDE: 79° 47.5' W ( -79.79170)
The primary bench mark is a disk located at the intersection of 11th Avenue and
Oak Harbor Boulevard, 11.34 m (37.2 ft) SSE of the south corner of a two-story
wood house, 11 m (36 ft) ENE of the centerline of 11th Avenue, 10.36 m (34.0 ft)
WSW of a large leaning oak tree, 5.18 m (17.0 ft) NNW of the centerline of Oak
Harbor Boulevard, and 0.3 m (1 ft) NW of power pole #79781. The bench mark is
set level with the ground, crimped to the top of a copper-clad steel rod driven
21.6 m (71 ft) to refusal, and encased in a pipe.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 6
Station ID: 8665387 PUBLICATION DATE: 02/05/2004
Name: HAMLIN CREEK, ISLE OF PALMS
SC
NOAA Chart: 11523 Latitude: 32° 47.2' N ( 32.78670)
USGS Quad: FORT MOULTRIE Longitude: 79° 47.5' W ( -79.79170)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 3 1935
DESIGNATION: 866 5387 3 TIDAL
MONUMENTATION: Bench Mark disk VM#: 4157
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 32° 47.2' N ( 32.78670) LONGITUDE: 79° 47.5' W ( -79.79170)
The bench mark is a disk set in the top of a concrete monument at the
intersection of Palm Boulevard and 11th Avenue, 21.03 m (69.0 ft) NNW of the
centerline of Palm Boulevard, 13.72 m (45.0 ft) ENE of the centerline of a
driveway to a split level brick residence on 11th Avenue, 7.47 m (24.5 ft) WSW
of the centerline of 11th Avenue, and 0.46 m (1.5 ft) above the ground. NOTE:
The bench mark was not recovered in 1992.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 6
Station ID: 8665387 PUBLICATION DATE: 02/05/2004
Name: HAMLIN CREEK, ISLE OF PALMS
SC
NOAA Chart: 11523 Latitude: 32° 47.2' N ( 32.78670)
USGS Quad: FORT MOULTRIE Longitude: 79° 47.5' W ( -79.79170)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: IOP 1963 AZIMUTH
DESIGNATION: IOP AZ MK
MONUMENTATION: Azimuth Mark disk VM#: 4158
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: CJ0611
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 32° 47.1' N ( 32.78500) LONGITUDE: 79° 47.6' W ( -79.79330)
The bench mark is a disk set in the top of a concrete monument, 9.94 m (32.6 ft)
ENE of the centerline of 9th Avenue, 7.44 m (24.4 ft) NNW of the centerline of
Carolina Boulevard, 3.17 m (10.4 ft) SSE of power pole #286221, 0.49 m (1.6 ft)
NE of a witness post, and level with the ground.
BENCH MARK STAMPING: HC NO 4 1975
DESIGNATION: 866 5387 TIDAL HC 4
MONUMENTATION: Tidal Station disk VM#: 4160
AGENCY: National Ocean Survey (NOS) IDB PID#: CJ0610
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID:
LATITUDE: 32° 47.2' N ( 32.78670) LONGITUDE: 79° 47.5' W ( -79.79170)
The bench mark is a disk located at Palm Boulevard between 9th and 10th Avenues,
46.79 m (153.5 ft) WSW of the centerline of 10th Avenue, 39.75 m (130.4 ft) WSW
of the NW corner of the porch of a two-story wood building, 13.44 m (44.1 ft) NE
of the NE corner of a wood house elevated on a concrete foundation, 10.67 m
(35.0 ft) SSE of the centerline of Palm Boulevard, and 3.02 m (9.9 ft) SW of
power pole #307944. The bench mark is set level with the ground, crimped to the
top of a copper-clad steel rod driven 17.1 m (56 ft) to refusal, and encased in
a PVC pipe filled with concrete.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 6
Station ID: 8665387 PUBLICATION DATE: 02/05/2004
Name: HAMLIN CREEK, ISLE OF PALMS
SC
NOAA Chart: 11523 Latitude: 32° 47.2' N ( 32.78670)
USGS Quad: FORT MOULTRIE Longitude: 79° 47.5' W ( -79.79170)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 5387 A 1982
DESIGNATION: 866 5387 A TIDAL
MONUMENTATION: Tidal Station disk VM#: 4161
AGENCY: National Ocean Survey (NOS) IDB PID#: CJ0613
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID:
LATITUDE: 32° 47.3' N ( 32.78830) LONGITUDE: 79° 47.5' W ( -79.79170)
The bench mark is a disk located at the end of 11th Avenue, 77 m (253 ft) WNW of
the centerline of Palm Boulevard, 29.02 m (95.2 ft) NW of bench mark HC NO 2
1975, 22.07 m (72.4 ft) NNE of the north corner of a brick house, 19.96 m (65.5
ft) WNW of the south corner of a two-story wood house, 6.04 m (19.8 ft) NNW of a
large oak tree, and 0.79 m (2.6 ft) ENE of power pole #151639. The bench mark
is set 12 cm (0.4 ft) below the ground, crimped to the top of a copper-clad
steel rod driven 9.8 m (32 ft) to refusal, and encased in a PVC pipe and
concrete kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 6
Station ID: 8665387 PUBLICATION DATE: 02/05/2004
Name: HAMLIN CREEK, ISLE OF PALMS
SC
NOAA Chart: 11523 Latitude: 32° 47.2' N ( 32.78670)
USGS Quad: FORT MOULTRIE Longitude: 79° 47.5' W ( -79.79170)
T I D A L D A T U M S
Tidal datums at HAMLIN CREEK, ISLE OF PALMS based on:
LENGTH OF SERIES: 2 YEARS
TIME PERIOD: January 1975 - December 1976
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 (11/21/1976) = 2.209
MEAN HIGHER HIGH WATER MHHW = 1.712
MEAN HIGH WATER MHW = 1.595
North American Vertical Datum NAVD88 = 0.957
MEAN SEA LEVEL MSL = 0.854
MEAN TIDE LEVEL MTL = 0.827
MEAN LOW WATER MLW = 0.059
MEAN LOWER LOW WATER MLLW = 0.000
LOWEST OBSERVED WATER LEVEL (12/21/1976) = -0.992
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
HC NO 2 1975 3.474 1.879
3 1935 4.371 2.776
IOP 1963 AZIMUTH 5.824 4.229
HC NO 4 1975 4.223 2.628
5387 A 1982 3.435 1.840
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 6
Station ID: 8665387 PUBLICATION DATE: 02/05/2004
Name: HAMLIN CREEK, ISLE OF PALMS
SC
NOAA Chart: 11523 Latitude: 32° 47.2' N ( 32.78670)
USGS Quad: FORT MOULTRIE Longitude: 79° 47.5' W ( -79.79170)
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.