U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 5 PUBLICATION DATE: 09/21/2000 Station ID: 8677344 SUPERCEDED DATE: 04/21/2003 Name: ST SIMONS LIGHTHOUSE, ST SIMONS ISLAND GEORGIA NOAA Chart: 11506 Latitude: 31° 7.9' N USGS Quad: BRUNSWICK EAST Longitude: 81° 23.8' W To reach the tidal bench marks from the intersection of U.S. Highway 17 and the Torras Causeway toll road in Brunswick, proceed 6.6 km (4.1 mi) east on the causeway to St. Simons Island, right (SSE) onto Kings Way for 3.5 km (2.2 mi) to Mallory Street, right on Mallory Street for 0.3 km (0.2 mi) to end at Neptune Park and a pier. The bench marks are located between the pier and St. Simons Lighthouse. The tide gage and staff were located on the SE corner of the pier. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: DESIGNATION: TIDAL 1 ALIAS: 867 7344 NO STAMPING 1 MONUMENTATION: Chiseled Cross VM#: 4929 AGENCY: US Coast and Geodetic Survey (USC&GS) PID#: BR0079 SETTING CLASSIFICATION: Foundation stones The primary bench mark is the center of a chiseled cross cut near the top of the vertical face of the upper course of foundation stones on the west side of St. Simons Lighthouse, nearly under the northern end of the windows, 0.30 m (1 ft) south of bench mark NO 2, and about 0.61 m (2.0 ft) above ground level. NOTE: The benchmark is historically referred to as I 1888. BENCH MARK STAMPING: NO 2 DESIGNATION: TIDAL 2 MONUMENTATION: Tidal Station disk VM#: 4924 AGENCY: US Coast and Geodetic Survey (USC&GS) PID#: BR0078 SETTING CLASSIFICATION: Lighthouse foundation The bench mark is a disk set vertically in the base on the west side of St. Simons Lighthouse, 0.30 m (1 ft) north of and 0.09 m (0.3 ft) below bench mark TIDAL 1, and 1 m (2 ft) above ground level. NOTE: The benchmark is historically referred to as No 2 1924.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 5 PUBLICATION DATE: 09/21/2000 Station ID: 8677344 SUPERCEDED DATE: 04/21/2003 Name: ST SIMONS LIGHTHOUSE, ST SIMONS ISLAND GEORGIA NOAA Chart: 11506 Latitude: 31° 7.9' N USGS Quad: BRUNSWICK EAST Longitude: 81° 23.8' W T I D A L B E N C H M A R K S BENCH MARK STAMPING: NO 3 1973 DESIGNATION: 867 7344 TIDAL 3 MONUMENTATION: Tidal Station disk VM#: 4926 AGENCY: National Ocean Survey (NOS) PID#: AI9971 SETTING CLASSIFICATION: Concrete sidewalk The bench mark is a disk set flush in the concrete sidewalk near the NW corner of the St. Simons pier, 5.38 m (17.7 ft) NNW of the NW corner concrete pier roof post, 2.69 m (8.83 ft) NNE of the south edge of the sidewalk at the shoreline, and 0.36 m (1.18 ft) ESE of the west edge of the sidewalk. BENCH MARK STAMPING: NO 4 1973 DESIGNATION: 867 7344 TIDAL 4 MONUMENTATION: Tidal Station disk VM#: 4927 AGENCY: National Ocean Survey (NOS) PID#: AI9972 SETTING CLASSIFICATION: Concrete monument The bench mark is a disk set flush in a concrete sidewalk near a mini-golf park on the east side of the pier parking lot, 10.73 m (35.2 ft) NE of the base of a large oak tree surrounded by a wooden deck, 7.42 m (24.3 ft) NW of the NW corner of a pavillion, and 6.07 m (19.9 ft) WNW of the east edge of the sidewalk. BENCH MARK STAMPING: NO 5 1973 DESIGNATION: 867 7344 TIDAL 5 MONUMENTATION: Tidal Station disk VM#: 4928 AGENCY: National Ocean Survey (NOS) PID#: AI9973 SETTING CLASSIFICATION: Concrete sidewalk The bench mark is a disk set in the southern end of a U-shaped concrete sidewalk at the southern end of a parking area between the casino and the Chamber of Commerce/Library and 1 m (4 ft) north of a power pole.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 5 PUBLICATION DATE: 09/21/2000 Station ID: 8677344 SUPERCEDED DATE: 04/21/2003 Name: ST SIMONS LIGHTHOUSE, ST SIMONS ISLAND GEORGIA NOAA Chart: 11506 Latitude: 31° 7.9' N USGS Quad: BRUNSWICK EAST Longitude: 81° 23.8' W T I D A L B E N C H M A R K S BENCH MARK STAMPING: ARP 1953 DESIGNATION: ARP MONUMENTATION: Topographic Station disk VM#: 16039 AGENCY: US Coast and Geodetic Survey (USC&GS) PID#: BR0062 SETTING CLASSIFICATION: Light pole base The bench mark is a disk set in an abandoned light pole base on the north edge of runway 8-26 (abandoned) at the Malcolm McKinnon Airport, 0.2 km (0.1 mi) SW of a sharp turn in Skylane Road, 244 m (800 ft) west of runway 15-33, the fifth abandoned light pole base west of the intersection of runways 15-33 and 8-26, and at ground level. BENCH MARK STAMPING: ARP 2 1959 DESIGNATION: ARP 2 MONUMENTATION: Topographic Station disk VM#: 16040 AGENCY: US Coast and Geodetic Survey (USC&GS) PID#: BR0073 SETTING CLASSIFICATION: Concrete monument The bench mark is a disk set in a concrete monument in the triangle formed by runways 8-26, the closed runway and the NE-SW taxiway at Malcolm McKinnon Airport, 178 m (585 ft) south of the wind sock and on a line that extends from the airport beacon through the wind sock, 24.23 m (79.5 ft) WNW of the south edge of the middle garage door on the back side of a metal hanger, 1.04 m (3.4 ft) NNE of a fiberglass witness post, 0.58 m (1.9 ft) SSW of a metal post, and at ground level.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 5 PUBLICATION DATE: 09/21/2000 Station ID: 8677344 SUPERCEDED DATE: 04/21/2003 Name: ST SIMONS LIGHTHOUSE, ST SIMONS ISLAND GEORGIA NOAA Chart: 11506 Latitude: 31° 7.9' N USGS Quad: BRUNSWICK EAST Longitude: 81° 23.8' W T I D A L D A T U M S Tidal datums at ST SIMONS LIGHTHOUSE, ST SIMONS ISLAND based on: LENGTH OF SERIES: 1 YEAR TIME PERIOD: July 1999 - June 2000 TIDAL EPOCH: 1960-1978 CONTROL TIDE STATION: 8670870 FORT PULASKI, SAVANNAH RIVER Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS: HIGHEST OBSERVED WATER LEVEL (09/28/1980) = 2.856 MEAN HIGHER HIGH WATER MHHW = 2.176 MEAN HIGH WATER MHW = 2.064 North American Vertical Datum NAVD88 = 1.355 MEAN SEA LEVEL MSL = 1.071 MEAN TIDE LEVEL MTL = 1.064 MEAN LOW WATER MLW = 0.063 MEAN LOWER LOW WATER MLLW = 0.000 LOWEST OBSERVED WATER LEVEL (02/20/2000) = -0.571 North American Vertical Datum (NAVD88) Bench Mark Elevation Information In METERS above: Stamping or Designation MLLW MHW TIDAL 1 5.237 3.173 NO 2 5.155 3.091 NO 3 1973 4.111 2.047 NO 4 1973 4.563 2.499 NO 5 1973 4.261 2.197 ARP 1953 5.605 3.541 ARP 2 1959 6.007 3.943
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 5 PUBLICATION DATE: 09/21/2000 Station ID: 8677344 SUPERCEDED DATE: 04/21/2003 Name: ST SIMONS LIGHTHOUSE, ST SIMONS ISLAND GEORGIA NOAA Chart: 11506 Latitude: 31° 7.9' N USGS Quad: BRUNSWICK EAST Longitude: 81° 23.8' 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.