U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 7
Station ID: 8671489 PUBLICATION DATE: 03/01/2023
Name: RICHMOND HILL, OGEECHEE RIVER
GA
NOAA Chart: 11509 Latitude: 31° 56.6' N ( 31.94297)
USGS Quad: RICHMOND HILL Longitude: 81° 17.4' W ( -81.28983)
To reach the tide station from the intersection of US-95 and SR-144 (Exit 90 of
US-95), head SE on SR-144 for 5.95 km (3.7 mi) to the intersection with Ford Way
and the main entrance to the Ford Plantation and turn left. Proceed to the main
security gate for the Ford Field and River Club and enter into the community.
Proceed east and north on Ford Way for 0.72 km (0.45 mi) to the intersection
with Dublin Dr and turn left. Proceed south and west on Dublin Dr for 2.4 km
(1.5 mi) to the intersection with Cherry Hill Dr and turn right. Proceed NE on
Cherry Hill Dr for 0.80 km (0.5 mi) to a circle and bear right, then left to
head NE on Magnolia Rd for 0.24 km (0.15 mi) to Club House Dr and make a left.
Continue on Club House Dr for 0.11 km (0.07 mi) to Little Lulu Ln and turn
right. Proceed NW on Little Lulu Ln for 0.98 km (0.61 mi) to the entrance for
Silk Hope Harbour and turn right into the community marina area. Proceed NE for
0.27 km (0.17 mi) to the Ogeechee Outfitters building and the tide station on
the NW corner of the seawall. The bench marks are located within the Ford
Plantation community, along the CSX train tracks, and along SR-144.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 1489 A 2021
DESIGNATION: 867 1489 A
MONUMENTATION: Tidal Station disk VM#: 24169
AGENCY: National Ocean Service IDB PID#:
SETTING CLASSIFICATION: Retaining wall OPUS PID#: BBHS37
LATITUDE: 31° 56.6' N ( 31.94347) LONGITUDE: 81° 17.3' W ( -81.28900)
The primary bench mark is a disk located 58.9 m (193.2 ft) NNE of the base of
the flag pole to the east of the Ogeechee Outfitters building, 31.9 m (104.7 ft)
SW of the center of the top of the boat ramp, 14.2 m (46.6 ft) NW of the north
corner of the NE wing wall for the culvert on the south side of the connecting
ditch, and 2.0 m (6.6 ft) SE of the northern corner of the wood platform on top
of the NW culvert. The mark is a brass disk set in the east corner of the
retaining wall for a culvert connecting the main waterway with the inland lake.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 7
Station ID: 8671489 PUBLICATION DATE: 03/01/2023
Name: RICHMOND HILL, OGEECHEE RIVER
GA
NOAA Chart: 11509 Latitude: 31° 56.6' N ( 31.94297)
USGS Quad: RICHMOND HILL Longitude: 81° 17.4' W ( -81.28983)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1489 B 2021
DESIGNATION: 867 1489 B
MONUMENTATION: Flange-encased Rod VM#: 24170
AGENCY: National Ocean Service IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod in sleeve OPUS PID#: BBHS38
LATITUDE: 31° 56.3' N ( 31.93861) LONGITUDE: 81° 17.7' W ( -81.29553)
The bench mark is a stainless-steel rod located 14.6 m (47.9 ft) SW of a lone
standing 3 ft (0.9 m) diameter long leaf pine, 11.6 m (38.1 ft) NW of the center
median of Ogeechee Lane, and 11.4 m (37.4 ft) NE of the easternmost gas lantern
on the north side of the bridge. The rod is driven to refusal and encased in a
5-inch PVC protective pipe with an NOS logo cap, recessed 8 cm (3 inches) below
grade.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 7
Station ID: 8671489 PUBLICATION DATE: 03/01/2023
Name: RICHMOND HILL, OGEECHEE RIVER
GA
NOAA Chart: 11509 Latitude: 31° 56.6' N ( 31.94297)
USGS Quad: RICHMOND HILL Longitude: 81° 17.4' W ( -81.28983)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: OGEECHEE N. BASE 1932
DESIGNATION: OGEECHEE NORTH BASE
MONUMENTATION: Triangulation Station disk VM#: 24172
AGENCY: US Coast and Geodetic Survey IDB PID#:
SETTING CLASSIFICATION: Set in top of concrete monument OPUS PID:
LATITUDE: 31° 56.5' N ( 31.94086) LONGITUDE: 81° 18.1' W ( -81.30142)
The mark is a disk located 51.2 m (168.0 ft) NE of reference mark 3, 15.6 m
(51.2 ft) SE of a 3-inch pipe projecting 1.0 m (3.3 ft) above the ground, 15.2 m
(49.9 ft) NW of the northern rail, 12.5 m (41.0 ft) north of a utility pole, 1.2
m (3.9 ft) SW of a tree with two orange marking ribbons, and 0.5 m (1.6 ft)
north of a witness post. The disk is set in a concrete monument flush with the
ground surface and 0.6 m (2.0 ft) below the level of the tracks.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 7
Station ID: 8671489 PUBLICATION DATE: 03/01/2023
Name: RICHMOND HILL, OGEECHEE RIVER
GA
NOAA Chart: 11509 Latitude: 31° 56.6' N ( 31.94297)
USGS Quad: RICHMOND HILL Longitude: 81° 17.4' W ( -81.28983)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: OGEECHEE N BASE NO 2 1932
DESIGNATION: OGEECHEE NORTH BASE RM 2
MONUMENTATION: Reference Mark disk VM#: 24175
AGENCY: US Coast and Geodetic Survey IDB PID#:
SETTING CLASSIFICATION: Set in top of a square concrete post OPUS PID:
LATITUDE: 31° 56.2' N ( 31.93733) LONGITUDE: 81° 18.2' W ( -81.30322)
The bench mark is a standard CGS reference mark disk located 12.3 meters (40.4
ft) SW from an 18 inch sweet gum tree, 6.25 meters (20.5 ft) west from the
northernmost corner of the main church building, 3.36 meters (11 ft) SE from the
northernmost corner of the wing on the west side of the church, and 2.93 meters
(9.6 ft) north from the inside corner of the church. It is set into the top of a
square concrete post 26.4 cm on side and projecting 9 cm (4 inches) above the
surface of the ground.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 7
Station ID: 8671489 PUBLICATION DATE: 03/01/2023
Name: RICHMOND HILL, OGEECHEE RIVER
GA
NOAA Chart: 11509 Latitude: 31° 56.6' N ( 31.94297)
USGS Quad: RICHMOND HILL Longitude: 81° 17.4' W ( -81.28983)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: N 393 1991
DESIGNATION: N 393
MONUMENTATION: Metal Rod VM#: 24179
AGENCY: National Geodetic Survey IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod w/o sleeve OPUS PID:
LATITUDE: 31° 56.9' N ( 31.94778) LONGITUDE: 81° 18.7' W ( -81.31083)
The mark is a stainless-steel rod located 12.2 m (40.0 ft) SW of the centerline
of the 2 southbound lanes, 6.1 m (20.0 ft) SSE of a flagpole, 4.6 m (15.1 ft)
ENE of east corner of the building, 0.9 m (3.0 ft) SE of the SE leg of the
Charlie Graingers sign, and 0.9 m (3.0 ft) NE of the NE edge of the sidewalk.
The rod is encased in a 5-inch (13 cm) National Geodetic Survey logo cap set
flush within the brick patio.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 7
Station ID: 8671489 PUBLICATION DATE: 03/01/2023
Name: RICHMOND HILL, OGEECHEE RIVER
GA
NOAA Chart: 11509 Latitude: 31° 56.6' N ( 31.94297)
USGS Quad: RICHMOND HILL Longitude: 81° 17.4' W ( -81.28983)
T I D A L D A T U M S
Tidal datums at RICHMOND HILL, OGEECHEE RIVER based on:
LENGTH OF SERIES: 3 MONTHS
TIME PERIOD: March 2022 - May 2022
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 = 1.589
MEAN HIGH WATER MHW = 1.531
MEAN SEA LEVEL MSL = 0.935
MEAN TIDE LEVEL MTL = 0.816
North American Vertical Datum NAVD88 = 0.730
MEAN LOW WATER MLW = 0.101
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
1489 A 2021 2.824 1.293
1489 B 2021 6.612 5.081
OGEECHEE N. BASE 1932 5.650 4.119
OGEECHEE N BASE NO 2 1932 6.602 5.071
N 393 1991 7.041 5.510
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 7 of 7
Station ID: 8671489 PUBLICATION DATE: 03/01/2023
Name: RICHMOND HILL, OGEECHEE RIVER
GA
NOAA Chart: 11509 Latitude: 31° 56.6' N ( 31.94297)
USGS Quad: RICHMOND HILL Longitude: 81° 17.4' W ( -81.28983)
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.