U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 8665475 PUBLICATION DATE: 03/09/2004
Name: LIMEHOUSE BRIDGE, STONO RIVER
SC
NOAA Chart: 11521 Latitude: 32° 47.2' N ( 32.78670)
USGS Quad: JOHNS ISLAND Longitude: 80° 6.3' W ( -80.10500)
To reach the tidal bench marks from intersection of U.S. Highway 17 and S.C.
Highway 20 proceed south on Highway 20 for 2.1 km (1.3 mi) to the John F.
Limehouse Memorial Bridge over the Intracoastal Waterway. The bench marks are
located in the parking area at the SE corner of the bridge. The tide gage and
staff were located on a county owned fishing pier east of the bridge.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 5475 A 1977
DESIGNATION: 866 5475 A TIDAL
MONUMENTATION: Tidal Station disk VM#: 4172
AGENCY: National Ocean Survey (NOS) IDB PID#: CK2417
SETTING CLASSIFICATION: Copper clad steel rod OPUS PID:
LATITUDE: 32° 47.1' N ( 32.78500) LONGITUDE: 80° 6.4' W ( -80.10670)
The primary bench mark is a located east of NE corner of the parking area, 35 m
(114 ft) ESE of power tower footing, 26.15 m (85.8 ft) SE of SW corner of county
pier, 9.66 m (31.7 ft) south of power pole #29SW-74Y, and 2.13 m (7.0 ft) west
of edge of marsh. The bench mark is set at ground level, crimped to the top of
a copper-clad steel rod driven 7.3 m (24 ft) to refusal, encased in a 4-inch PVC
pipe and concrete kickblock. NOTE: Mark reported to be in poor condition in
2001 by NGS.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 8665475 PUBLICATION DATE: 03/09/2004
Name: LIMEHOUSE BRIDGE, STONO RIVER
SC
NOAA Chart: 11521 Latitude: 32° 47.2' N ( 32.78670)
USGS Quad: JOHNS ISLAND Longitude: 80° 6.3' W ( -80.10500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 5475 B 1977
DESIGNATION: 866 5475 B TIDAL
MONUMENTATION: Tidal Station disk VM#: 4173
AGENCY: National Ocean Survey (NOS) IDB PID#: CK2416
SETTING CLASSIFICATION: Tower foundation OPUS PID:
LATITUDE: 32° 47.1' N ( 32.78500) LONGITUDE: 80° 6.4' W ( -80.10670)
The bench mark is a disk set flush in concrete footing of the tower, located in
the SE corner of the NW post of power tower base, 28.35 m (93.0 ft) west of SW
corner of county pier and, 24.54 m (80.5 ft) ENE of fourth bridge support of
southern half of bridge.
BENCH MARK STAMPING: 5475 C 1977
DESIGNATION: 866 5475 C TIDAL
MONUMENTATION: Tidal Station disk VM#: 4174
AGENCY: National Ocean Survey (NOS) IDB PID#: CK2418
SETTING CLASSIFICATION: Copper clad steel rod OPUS PID#: CK2418
LATITUDE: 32° 47.1' N ( 32.78500) LONGITUDE: 80° 6.4' W ( -80.10670)
The bench mark is a disk located east of SE corner of parking area, 25.09 m
(82.3 ft) north of unnumbered power pole on east side of parking area, 16.15 m
(53.0 ft) east from approximate center of parking area, and 2.44 m (8.0 ft) west
of edge of marsh. The bench mark is set at ground level, crimped to the top of
a copper-clad steel rod driven 7.3 m (24 ft) to refusal, encased in a 4-inch PVC
and concrete kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 8665475 PUBLICATION DATE: 03/09/2004
Name: LIMEHOUSE BRIDGE, STONO RIVER
SC
NOAA Chart: 11521 Latitude: 32° 47.2' N ( 32.78670)
USGS Quad: JOHNS ISLAND Longitude: 80° 6.3' W ( -80.10500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 5475 D 1977
DESIGNATION: 866 5475 D TIDAL
MONUMENTATION: Tidal Station disk VM#: 4175
AGENCY: National Ocean Survey (NOS) IDB PID#: CK2415
SETTING CLASSIFICATION: In bridge OPUS PID:
LATITUDE: 32° 47.1' N ( 32.78500) LONGITUDE: 80° 6.4' W ( -80.10670)
The bench mark is a disk set flush in the bridge foundation, located in the SE
corner of Limehouse Bridge, 53.43 m (175.3 ft) WSW of bench mark 5467 E 1977, 8
m (26 ft) west of cluster of mimosa trees on NW side of parking area, and 4.24 m
(13.9 ft) east of centerline of S.C. Highway 20.
BENCH MARK STAMPING: 5475 E 1977
DESIGNATION: 866 5475 E TIDAL
MONUMENTATION: Tidal Station disk VM#: 4176
AGENCY: National Ocean Survey (NOS) IDB PID#: CK2419
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID:
LATITUDE: 32° 47.1' N ( 32.78500) LONGITUDE: 80° 6.4' W ( -80.10670)
The bench mark is a disk located near the SW corner of parking area, 35.75 m
(117.3 ft) north of SW corner of parking area, 34.50 m (113.2 ft) west of bench
mark 5475 C 1977, and 13 m (43 ft) east of S.C. Highway 20. The bench mark is
set at ground level, crimped to the top of a copper-clad steel rod driven 4.9 m
(16 ft) to refusal, 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
Station ID: 8665475 PUBLICATION DATE: 03/09/2004
Name: LIMEHOUSE BRIDGE, STONO RIVER
SC
NOAA Chart: 11521 Latitude: 32° 47.2' N ( 32.78670)
USGS Quad: JOHNS ISLAND Longitude: 80° 6.3' W ( -80.10500)
T I D A L D A T U M S
Tidal datums at LIMEHOUSE BRIDGE, STONO RIVER based on:
LENGTH OF SERIES: 4 MONTHS
TIME PERIOD: July 1977 - October 1977
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:
MEAN HIGHER HIGH WATER MHHW = 1.873
MEAN HIGH WATER MHW = 1.777
MEAN SEA LEVEL MSL = 1.089
North American Vertical Datum NAVD88 = 1.053
MEAN TIDE LEVEL MTL = 0.926
MEAN LOW WATER MLW = 0.075
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
5475 A 1977 2.516 0.739
5475 B 1977 2.271 0.494
5475 C 1977 2.432 0.655
5475 D 1977 5.882 4.105
5475 E 1977 2.664 0.887
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 8665475 PUBLICATION DATE: 03/09/2004
Name: LIMEHOUSE BRIDGE, STONO RIVER
SC
NOAA Chart: 11521 Latitude: 32° 47.2' N ( 32.78670)
USGS Quad: JOHNS ISLAND Longitude: 80° 6.3' W ( -80.10500)
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.