U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 4
Station ID: 8674301 PUBLICATION DATE: 07/12/2012
Name: DAYMARK #135, SOUTH NEWPORT R.
GA
NOAA Chart: 11510 Latitude: 31° 34.5' N ( 31.57500)
USGS Quad: SAPELO SOUND Longitude: 81° 11.4' W ( -81.19000)
To reach the tidal bench marks from I95 through Georgia take exit 58 for
GA-57/GA-99 toward Townsend Rd/Eulonsa for 0.32 km (.2 mi). Turn right onto
GA-99 S (signs for Georgia 99/Eulonsa) for 7.88 km (4.9 mi). Turn left onto
Susan Baker Dr for 2.57 km (1.6 mi) until you reach public boat ramp. Proceed
by boat east on Sapelo river towards the Sapelo sound for 16.98 km (10.55 mi) to
channel marker R "138", proceed north on the South Newport river for 2.45 km
(1.52 mi) to channel marker G "135". The station is on channel marker G "135"
and bench marks are onshore east of station.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 4301 F 2012
DESIGNATION: 867 4301 F
MONUMENTATION: Metal Rod VM#: 20367
AGENCY: ASMS IDB PID#:
SETTING CLASSIFICATION: Stainles steel rod OPUS PID#: BBCR06
LATITUDE: 31° 34.5' N ( 31.57506) LONGITUDE: 81° 11.3' W ( -81.18806)
The primary bench mark is a flange-encased rod located 23.2 km (14.4 mi)
east-northeast of Eulonia, 23.0 km (14.3 mi) southeast of Seabrook and 12.9 km
(8.0 mi) east of Shellman Bluff. It is 216.5 m (710.16 ft) south of NOAA/NOS
tide station 867 4301, 205.0 ft (62.5 m) southeast of bench mark 4301 E, 51.8 m
(170.0 ft) northwest of the west edge of a woods, 19.2 m (63.0 ft) east Of west
edge of shoreline. The datum point is set 0.2 m (0.5 ft) above the ground,
being the top of a stainless steel rod driven 11.0 m (36.1 ft) to refusal and
encased in a 5-inch nos logo cap.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 4
Station ID: 8674301 PUBLICATION DATE: 07/12/2012
Name: DAYMARK #135, SOUTH NEWPORT R.
GA
NOAA Chart: 11510 Latitude: 31° 34.5' N ( 31.57500)
USGS Quad: SAPELO SOUND Longitude: 81° 11.4' W ( -81.19000)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 4301 G 2012
DESIGNATION: 867 4301 G
MONUMENTATION: Drill Hole VM#: 20368
AGENCY: ASMS IDB PID#:
SETTING CLASSIFICATION: Stainles steel rod OPUS PID:
LATITUDE: 31° 34.5' N ( 31.57475) LONGITUDE: 81° 11.3' W ( -81.18764)
The bench mark is a flange-encased rod located 14.4 mi (23.2 km) east northeast
of Eulonia, 23.0 km (14.3 mi) southeast of Seabrook and 12.9 km (8.0 mi) east
of Shellman Bluff. It is 253.0 m (830.02 ft) south of NOAA/NOS tide station 867
4301, 54.9 m (180.0 ft) east-northeast of bench mark 8674301 F, 54.9 m (180.0
ft) northwest of bench mark 8674301 H, 3.0 m (10.0 ft) south of a large bush.
The bench mark is set 0.2 m (0.5 ft) above the ground, being the top of a
stainless steel rod driven 11.0 m (36.1 ft) to refusal and encased in a 5-inch
logo cap.
BENCH MARK STAMPING: 4301 H 2012
DESIGNATION: 867 4301 H
MONUMENTATION: Metal Rod VM#: 20369
AGENCY: ASMS IDB PID#:
SETTING CLASSIFICATION: Stainles steel rod OPUS PID:
LATITUDE: 31° 34.5' N ( 31.57428) LONGITUDE: 81° 11.2' W ( -81.18744)
The bench mark is a flange-encased rod located 23.2 km (14.4 mi) east-northeast
of Eulonia, 23.0 km (14.3 mi) southeast of Seabrook and 12.9 km (8.0 mi) east of
Shellman Bluff. It is 319.1 m (1047.02 ft) south of NOAA/NOS tide station 867
4301, 54.9 m (180.0 ft) southeast of bench mark 8674301 g, 13.4 m (44.0 ft)
southwest of a palm tree, 4.0 m (13.0 ft) northwest of a palm tree. The bench
mark is set 0.2 m (0.5 ft) above the ground, being the top of a stainless steel
rod driven 11.0 m (36.1 ft) to refusal and encased in a 5-inch logo cap.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 4
Station ID: 8674301 PUBLICATION DATE: 07/12/2012
Name: DAYMARK #135, SOUTH NEWPORT R.
GA
NOAA Chart: 11510 Latitude: 31° 34.5' N ( 31.57500)
USGS Quad: SAPELO SOUND Longitude: 81° 11.4' W ( -81.19000)
T I D A L D A T U M S
Tidal datums at DAYMARK #135, SOUTH NEWPORT R. based on:
LENGTH OF SERIES: 2 MONTHS
TIME PERIOD: March 2012 - April 2012
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8670870 FORT PULASKI, SAVANNAH RIVER
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 2.275
MEAN HIGH WATER MHW = 2.166
MEAN SEA LEVEL MSL = 1.156
MEAN TIDE LEVEL MTL = 1.115
MEAN LOW WATER MLW = 0.063
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
4301 F 2012 2.465 0.299
4301 G 2012 2.878 0.712
4301 H 2012 2.646 0.480
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 4
Station ID: 8674301 PUBLICATION DATE: 07/12/2012
Name: DAYMARK #135, SOUTH NEWPORT R.
GA
NOAA Chart: 11510 Latitude: 31° 34.5' N ( 31.57500)
USGS Quad: SAPELO SOUND Longitude: 81° 11.4' W ( -81.19000)
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.